
[Federal Register Volume 81, Number 49 (Monday, March 14, 2016)]
[Proposed Rules]
[Pages 13451-13528]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-05493]



[[Page 13451]]

Vol. 81

Monday,

No. 49

March 14, 2016

Part II





Department of Transportation





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 Federal Aviation Administration





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14 CFR Parts 21, 23, 35, et al.





 Revision of Airworthiness Standards for Normal, Utility, Acrobatic, 
and Commuter Category Airplanes; Proposed Rule

  Federal Register / Vol. 81 , No. 49 / Monday, March 14, 2016 / 
Proposed Rules  

[[Page 13452]]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Parts 21, 23, 35, 43, 91, 121, and 135

[Docket No.: FAA-2015-1621; Notice No. 16-01]
RIN 2120-AK65


Revision of Airworthiness Standards for Normal, Utility, 
Acrobatic, and Commuter Category Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to amend its airworthiness standards for 
normal, utility, acrobatic, and commuter category airplanes by removing 
current prescriptive design requirements and replacing them with 
performance-based airworthiness standards. The proposed standards would 
also replace the current weight and propulsion divisions in small 
airplane regulations with performance- and risk-based divisions for 
airplanes with a maximum seating capacity of 19 passengers or less and 
a maximum takeoff weight of 19,000 pounds or less. The proposed 
airworthiness standards are based on, and would maintain, the level of 
safety of the current small airplane regulations. Finally, the FAA 
proposes to adopt additional airworthiness standards to address 
certification for flight in icing conditions, enhanced stall 
characteristics, and minimum control speed to prevent departure from 
controlled flight for multiengine airplanes. This notice of proposed 
rulemaking addresses the Congressional mandate set forth in the Small 
Airplane Revitalization Act of 2013.

DATES: Send comments on or before May 13, 2016.

ADDRESSES: Send comments identified by docket number FAA-2015-1621 
using any of the following methods:
     Federal eRulemaking Portal: Go to http://www.regulations.gov and follow the online instructions for sending your 
comments electronically.
     Mail: Send comments to Docket Operations, M-30; U.S. 
Department of Transportation (DOT), 1200 New Jersey Avenue SE., Room 
W12-140, West Building Ground Floor, Washington, DC 20590-0001.
     Hand Delivery or Courier: Take comments to Docket 
Operations in Room W12-140 of the West Building Ground Floor at 1200 
New Jersey Avenue SE., Washington, DC, between 9 a.m. and 5 p.m., 
Monday through Friday, except Federal holidays.
     Fax: Fax comments to Docket Operations at 202-493-2251.
    Privacy: In accordance with 5 U.S.C. 553(c), DOT solicits comments 
from the public to better inform its rulemaking process. DOT posts 
these comments, without edit, including any personal information the 
commenter provides, to www.regulations.gov, as described in the system 
of records notice (DOT/ALL-14 FDMS), which can be reviewed at http://www.dot.gov/privacy.
    Docket: Background documents or comments received may be read at 
http://www.regulations.gov at any time. Follow the online instructions 
for accessing the docket or go to the Docket Operations in Room W12-140 
of the West Building Ground Floor at 1200 New Jersey Avenue SE., 
Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays.

FOR FURTHER INFORMATION CONTACT: For technical questions concerning 
this action, contact Lowell Foster, Regulations and Policy, ACE-111, 
Federal Aviation Administration, 901 Locust St., Kansas City, MO 64106; 
telephone (816) 329-4125; email lowell.foster@faa.gov.

SUPPLEMENTARY INFORMATION: Later in this preamble, under the Additional 
Information section, we discuss how you can comment on this proposal 
and how we will handle your comments. This discussion includes related 
information about the docket, privacy, and the handling of proprietary 
or confidential business information. We also discuss how you can get a 
copy of this proposal and related rulemaking documents.
    All sections of part 23 would contain proposed revisions, except 
the FAA would not make any substantive changes to the following 
sections: Sec. Sec.  23.1457, Cockpit Voice Recorders, and 23.1459, 
Flight Data Recorders. The only proposed changes to Sec.  23.1459 would 
be for the purpose of aligning part 23 references. These sections are 
nevertheless included in this proposed revision for context.

Table of Contents

I. Executive Summary
    A. Purpose and History of the Proposed Performance-Based 
Standards
    B. Summary of Major Provisions
    1. Performance Standards and Airplane Crashworthiness
    2. Loss of Control
    3. Icing Certification Standards
    C. Cost and Benefits
II. Authority for This Rulemaking
III. Background
    A. Part 23 History
    B. New Safety Requirements
    C. Benefits for the Existing Fleet
    D. Conforming Amendments and Other Minor Amendments
    E. Public Policy Implementation
    1. Regulatory Planning and Review
    2. Consensus Standards
    3. International Cooperation Efforts for Reorganizing Part 23
    F. Means of Compliance
    G. FAA Strategic Initiatives
IV. Discussion of Proposal
    A. Reorganization of Airworthiness Standards Based on Risk and 
Performance
    B. Introduction of Simple Airplanes
    C. Establishing Performance-Based Standards and the Use of Means 
of Compliance
    D. Crashworthiness as an Illustration of the Benefits of 
Performance-Based Regulations
    E. Additional Requirements To Prevent Loss of Control
    F. Additional Requirements for Flight in Icing Conditions
    G. Production of Replacement and Modification Articles
V. Key Terms and Concepts Used in This Document
VI. Discussion of the Proposed Regulatory Amendments
    A. Part 23, Airworthiness Standards
    1. Subpart A--General
    2. Subpart B--Flight
    3. Subpart C--Structures
    4. Subpart D--Design and Construction
    5. Subpart E--Powerplant
    6. Subpart F--Equipment
    7. Subpart G--Flightcrew Interface and Other Information
    8. Appendices to Part 23
    B. Miscellaneous Amendments
    1. Production of Replacement and Modification Articles (Sec.  
21.9)
    2. Designation of Applicable Regulations (Sec.  21.17)
    3. Issuance of Type Certificate: Primary Category Aircraft 
(Sec.  21.24)
    4. Flight Tests (Sec.  21.35)
    5. Instructions for Continued Airworthiness and Manufacturer's 
Maintenance Manuals Having Airworthiness Limitations Sections (Sec.  
21.50)
    6. Designation of Applicable Regulations (Sec.  21.101)
    7. Applicability (Sec.  35.1)
    8. Fatigue Limits and Evaluation (Sec.  35.37)
    9. Altimeter System Test and Inspection (Appendix E to Part 43)
    10. Powered Civil Aircraft With Standard Category U.S. 
Airworthiness Certificates: Instrument and Equipment Requirements 
(Sec.  91.205)
    11. Restricted Category Civil Aircraft: Operating Limitations 
(Sec.  91.313)
    12. Increased Maximum Certification Weights for Certain 
Airplanes Operated in Alaska (Sec.  91.323)
    13. Second In Command Requirements (Sec.  91.531)
    14. Additional Emergency Equipment (Sec.  121.310)
    15. Additional Airworthiness Requirements (Sec.  135.169)

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VII. Regulatory Notices and Analyses
    A. Regulatory Evaluation Summary
    B. Initial Regulatory Flexibility Determination
    C. International Trade Impact Assessment
    D. Unfunded Mandates Assessment
    E. Paperwork Reduction Act
    F. International Compatibility and Cooperation
    G. Environmental Analysis
    H. Regulations Affecting Intrastate Aviation in Alaska
VIII. Executive Order Determination
    A. Executive Order 13132, Federalism
    B. Executive Order 13211, Regulations That Significantly Affect 
Energy Supply, Distribution, or Use
IX. Additional Information
    A. Comments Invited
    B. Availability of Rulemaking Documents
Appendix 1 to the Preamble--Current to Proposed Regulations Cross-
Reference Table
Appendix 2 to the Preamble--Abbreviations and Acronyms Frequently 
Used In This Document

I. Executive Summary

A. Purpose and History of the Proposed Performance-Based Standards

    Part 23 of Title 14 of the Code of Federal Regulations (14 CFR) 
prescribes airworthiness standards for issuance and amendment of type 
certificates for airplanes with a passenger-seating configuration of 19 
or less and a maximum certificated takeoff weight of 19,000 pounds or 
less. Airplanes certificated under part 23 are typically used for 
recreation, training, personal travel, and limited commercial 
applications.
    The current part 23 airworthiness standards are largely 
prescriptive, meaning that they describe detailed design requirements, 
and are based on airplane designs from the 1950's and 1960's. As a 
result of this prescriptive framework, the FAA often requires a design 
approval applicant seeking to incorporate new or innovative technology 
to provide additional documentation that typically results in the FAA's 
issuance of special conditions, exemptions, or equivalent level of 
safety (ELOS) findings.\1\ The FAA recognizes that these additional 
procedures and requirements are costly to the FAA and industry, act as 
barriers to certification, and discourage innovation. Therefore, to 
encourage the installation of new safety-enhancing technology and 
streamline the certification process, the FAA proposes replacing the 
prescriptive requirements found in the current part 23 with 
performance-based standards.
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    \1\ Special conditions give the manufacturer permission to build 
the aircraft, engine or propeller with additional capabilities not 
addressed in the regulations. A petition for exemption is a request 
to the FAA by an individual or entity asking for relief from the 
requirements of a regulation. Equivalent level of safety findings 
are made when literal compliance with a certification regulation 
cannot be shown and compensating factors exist which can be shown to 
provide an equivalent level of safety. 14 CFR parts 11 and 21 
provides information on special conditions and exemptions. FAA Order 
8110-112A provides standard procedures for issue paper and 
equivalent level of safety memoranda.
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    The FAA believes this proposed rulemaking would maintain the level 
of safety associated with current part 23, while providing greater 
flexibility to applicants seeking certification of their airplane 
designs. By doing so, this proposed rulemaking would hasten the 
adoption of safety enhancing technology in type-certificated products 
while reducing regulatory time and cost burdens for the aviation 
industry and FAA. This proposed rulemaking would also reflect the FAA's 
safety continuum philosophy,\2\ which balances the need for an 
acceptable level of safety with the societal burden of achieving that 
level safety, across the broad range of airplane types certificated 
under part 23.
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    \2\ The FAA's safety continuum philosophy is that one level of 
safety may not be appropriate for all aviation. The FAA accepts 
higher levels of risk, with correspondingly fewer requirements for 
the demonstration of compliance, when aircraft are used for personal 
transportation.
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    This proposed rulemaking is the result of an effort the FAA began 
in 2008 to re-evaluate the way it sets standards for different types of 
airplanes. Through this effort, a joint FAA and industry team produced 
the Part 23 Certification Process Study \3\ (CPS), which reviewed the 
life cycle of part 23 airplanes to evaluate certification processes and 
develop recommendations. Two key recommendations were to (1) reorganize 
part 23 based on airplane performance and complexity rather than the 
existing weight and propulsion divisions, and (2) permit the use of 
consensus standards as a means to keep pace with rapidly increasing 
design complexity in the aviation industry.
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    \3\ See www.regulations.gov (Docket # FAA-2015-1621).
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    In 2010, with the CPS as a foundation, the FAA conducted a Part 23 
Regulatory Review and held meetings with the public and industry to 
gain input on revising part 23. These meetings confirmed strong public 
and industry support for the CPS recommendations to revise part 23.
    In 2011, the FAA formed the Part 23 Reorganization ARC to consider 
further the CPS recommendation to reorganize part 23 based on airplane 
performance and complexity and to investigate the use of consensus 
standards. The ARC recommendations,\4\ published in 2013, echo the CPS 
recommendations.
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    \4\ See www.regulations.gov (Docket # FAA-2015-1621).
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    On January 7, 2013, Congress passed the Federal Aviation 
Modernization and Reform Act of 2012 \5\ (Public Law 112-95; 49 U.S.C. 
40101 note) (FAMRA), which requires the Administrator, in consultation 
with the aviation industry, to assess the aircraft certification and 
approval process. Based on the ARC recommendations and in response to 
FAMRA, the FAA began work on this proposed rulemaking on September 24, 
2013. Subsequently, on November 27, 2013, Congress passed the Small 
Airplane Revitalization Act of 2013 (Public Law 113-53, 49 U.S.C. 44704 
note) (SARA), which requires the FAA to issue a final rule revising the 
certification requirements for small airplanes by--
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    \5\ http://www.gpo.gov/fdsys/pkg/CRPT-112hrpt381/pdf/CRPT-112hrpt381.pdf.
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     Creating a regulatory regime that will improve safety and 
decrease certification costs;
     Setting safety objectives that will spur innovation and 
technology adoption;
     Replacing prescriptive rules with performance-based 
regulations; and
     Using consensus standards to clarify how safety objectives 
may be met by specific designs and technologies.
    The FAA believes that the performance-based-standards component of 
this proposal complies with the FAMRA and the SARA because it would 
improve safety, reduce regulatory compliance costs, and spur innovation 
and the adoption of new technology. This proposal would replace the 
weight-and propulsion-based prescriptive airworthiness standards in 
part 23 with performance- and risk-based airworthiness standards for 
airplanes with a maximum seating capacity of 19 passengers or less and 
a maximum takeoff weight of 19,000 pounds or less. The proposed 
standards would maintain the level of safety associated with the 
current part 23, while also facilitating the adoption of new and 
innovative technology in general aviation (GA) airplanes.

B. Summary of Major Provisions

    This proposal to revise part 23 has two principal components: 
Establishing a performance-based regulatory regime and adding new 
certification standards for loss of control (LOC) and icing. Where the 
FAA proposes to establish new certification requirements, these 
requirements would be adopted within the same performance-based 
framework proposed for part 23 as a whole.

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1. Performance Standards and Airplane Crashworthiness
    Airplane crashworthiness and occupant safety is an example of how 
moving towards performance-based standards and providing greater 
flexibility to industry would increase aviation safety. Although the 
FAA has over the years incrementally amended part 23 to enhance 
occupant safety, these amendments have focused on individual system 
components, rather than the safety of the system as a whole. By 
building greater flexibility into FAA regulations governing crash 
testing, this proposal would allow the aviation industry to develop and 
implement novel solutions.
2. Loss of Control
    One proposed revision to part 23 would improve general aviation 
safety by creating additional certification standards to reduce LOC 
accidents. Inadvertent stalls resulting in airplane LOC are the most 
common cause of small airplane fatal accidents. These LOC accidents 
frequently occur in the traffic pattern or at low altitudes, where the 
airplane is too low for a pilot to recover control before impacting the 
ground. The proposed revisions would require applicants to use new 
design approaches and technologies to improve airplane stall 
characteristics and pilot situational awareness to prevent such 
accidents.
3. Icing Certification Standards
    Another proposed revision to part 23 would improve GA safety by 
addressing severe icing conditions. In the 1990s, the FAA became aware 
of the need to expand the icing conditions considered during the 
certification of airplanes and turbine aircraft engines. In particular, 
the FAA determined that revised icing certification standards should 
include Supercooled Large Drops (SLD),\6\ mixed phase, and ice 
crystals.
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    \6\ SLD conditions include freezing drizzle and freezing rain, 
which contain drops larger than those specified in appendix C to 
part 25, and can accrete aft of wing leading edge ice protection 
systems.
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    This proposed rule would require manufacturers that choose to 
certify an airplane for flight in SLD to demonstrate safe operations in 
SLD conditions. For those manufacturers who choose instead to certify 
an airplane with a prohibition against flight in SLD conditions, this 
proposed rule would require a means for detecting SLD conditions and 
showing the airplane can safely exit such conditions. Industry has 
indicated that these requirements would not impose significant 
additional cost burden on industry because many manufacturers already 
have equipped recent airplanes with technology to meet the standards 
for detecting and exiting SLD conditions in accordance with current FAA 
guidance.

C. Cost and Benefits

    The goal of this proposal is to create a cost-effective approach to 
certification that facilitates the adoption of new safety enhancing 
technologies and allows for alternative means of compliance. The FAA 
has analyzed the benefits and costs associated with this NPRM. If the 
proposed rule saves only one human life, for example, by improving 
stall characteristics and stall warnings, that alone would result in 
benefits outweighing the costs. The following table shows these 
results.

                                 Estimated Benefits and Costs From 2017 to 2036
                                                [2014 $ millions]
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                                                      Costs      Safety benefits + cost savings = total benefits
----------------------------------------------------------------------------------------------------------------
Total..........................................            $3.9  $19.6 + $12.6 = $32.2.
Present value..................................             3.9  $6.2 + $5.8 = $12.0.
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    Accordingly, the FAA has determined that the proposed rule would be 
cost beneficial.

II. Authority for This Rulemaking

    The FAA's authority to issue rules on aviation safety is found in 
Title 49 of the United States Code. Subtitle I, Section 106 describes 
the authority of the FAA Administrator. Subtitle VII, Aviation 
Programs, describes in more detail the scope of the agency's authority.
    This rulemaking is promulgated under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701. Under that section, 
the FAA is charged with promoting safe flight of civil airplanes in air 
commerce by prescribing minimum standards required in the interest of 
safety for the design and performance of airplanes. This regulation is 
within the scope of that authority because it prescribes new 
performance-based safety standards for the design of normal, utility, 
acrobatic, and commuter category airplanes.
    Additionally, this rulemaking addresses the Congressional mandate 
set forth in the Small Airplane Revitalization Act of 2013 (Public Law 
113-53; 49 U.S.C. 44704 note) (SARA). Section 3 of SARA requires the 
Administrator to issue a final rule to advance the safety and continued 
development of small airplanes by reorganizing the certification 
requirements for such airplanes under part 23 to streamline the 
approval of safety advancements. SARA directs that the rule address 
specific recommendations of the 2013 Part 23 Reorganization Aviation 
Rulemaking Committee (ARC).

III. Background

    The range of airplanes certificated under part 23 is diverse in 
terms of performance capability, number of passengers, design 
complexity, technology, and intended use. Currently, each part 23 
airplane's certification requirements are determined by reference to a 
combination of factors, including weight, number of passengers, and 
propulsion type. The resulting divisions (i.e., normal, utility, 
acrobatic, and commuter categories) historically were appropriate 
because there was a clear relationship between the propulsion and 
weight of the airplane and its associated performance and complexity.
    Technological developments have altered the dynamics of that 
relationship. For example, high-performance and complex airplanes now 
exist within the weight range that historically was occupied by only 
light and simple airplanes. The introduction of high-performance, 
lightweight airplanes required subsequent amendments of part 23 to 
include more stringent and demanding standards--often based on the part 
25 requirements for larger transport category airplanes--to ensure an 
adequate level of safety for airplanes under part 23. The unintended 
result is that some of the more stringent and demanding standards for 
high-performance airplanes now apply to the

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certification of simple and low-performance airplanes.

A. Part 23 History

    Part 23 originated from performance-based requirements developed by 
the Bureau of Air Commerce and the Civil Aeronautics Administration in 
the 1930s. These regulations were contained in specific Civil Air 
Regulations (CAR) for the certification of aircraft (i.e., CAR 3, 4, 
and 4a). These requirements, along with various bulletins and related 
documents, were subsequently revised and first published as 14 CFR part 
23 in 1964 (29 FR 17955, December 18, 1964). Over the past five decades 
and after numerous amendments, part 23 has evolved into a body of 
highly complex and prescriptive requirements attempting to codify 
specific design requirements, address specific problems encountered 
during prior certification projects, and respond to specific 
recommendations from the National Transportation Safety Board (NTSB).
    Although the intent of the prescriptive language contained in 
current part 23 was to increase the level of safety, prevent confusion, 
and clarify ambiguities, the current regulations have also restrained 
manufacturers' ability to employ new designs and testing methodologies. 
The FAA believes moving towards performance-based standards should 
significantly reduce or eliminate barriers to innovation and facilitate 
the introduction of new safety-enhancing technologies.
    In 2008, the FAA conducted a review of part 23 by initiating the 
Part 23 CPS. Collaborating with industry, the team's challenge was to 
determine the future of part 23, given today's current products and 
anticipated future products. The team identified opportunities for 
improvements by examining the entire life cycle of a part 23 airplane. 
The CPS recommended reorganizing part 23 using criteria focused on 
performance and design complexity. The CPS also recommended that the 
FAA implement general airworthiness requirements, with the means of 
compliance defined in industry consensus standards standards. In 2010, 
following the publication of the Part 23 CPS, the FAA held a series of 
public meetings to seek feedback concerning the findings and 
recommendations. Overall, the feedback was supportive of and in some 
cases augmented the CPS recommendations.
    One notable difference between the CPS findings and the public 
feedback was the public's request that the FAA revise part 23 
certification requirements for simple, entry-level airplanes. Over the 
past two decades, part 23 standards have become more complex as 
industry has generally shifted towards correspondingly complex, high-
performance airplanes. This transition has placed an increased burden 
on applicants seeking to certificate smaller, simpler airplanes. Public 
comments requested that the FAA focus on reducing the costs and time 
burden associated with certificating small airplanes by restructuring 
the requirements based on perceived risk. The safety risk for most 
simple airplane designs is typically low.
    On August 15, 2011, the Administrator chartered the Part 23 
Reorganization ARC to consider the following CPS recommendations--
     Recommendation 1.1.1--Reorganize part 23 based on airplane 
performance and complexity, rather than the existing weight and 
propulsion divisions; and
     Recommendation 1.1.2--Certification requirements for part 
23 airplanes should be written on a broad, general, and progressive 
level, segmented into tiers based on complexity and performance.
    The ARC's recommendations took into account the FAMRA, which 
requires the Administrator, in consultation with the aviation industry, 
to assess the aircraft certification and approval process. The purpose 
of the ARC's assessment was to develop recommendations for streamlining 
and reengineering the certification process to improve efficiency, 
reduce costs, and ensure that the Administrator can conduct 
certifications and approvals in a manner that supports and enables the 
development of new products and technologies and the global 
competitiveness of the United States aviation industry.\7\ FAMRA also 
directs the Administrator to consider the recommendations from the Part 
23 Certification Process Study.\8\
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    \7\ Section 312(c)
    \8\ Section 312 (b)(6)
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    ARC membership represented a broad range of of stakeholder 
perspectives, including U.S. and international manufacturers, trade 
associations, and foreign civil aviation authorities. The ARC was 
supported by FAA subject matter experts from all affected lines of 
business, from design and production certification to continued 
airworthiness and alterations. The following table identifies ARC 
participants:

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                           U.S. Manufacturers
------------------------------------------------------------------------
Avidyne.....................  Bendix-King.........  Cessna.
Cirrus......................  Continental Motors..  Cub Crafters.
GAMI........................  Garmin..............  Hawker Beechcraft.
Honda.......................  Honeywell...........  Kestrel.
Lockheed Martin.............  Rockwell-Collins....  Quest.
Sensenich Propellers........  Tamarack Aero.......  TruTrak.
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                           U.S. Organizations
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Aircraft Electronics          Aircraft Owners and   ASTM.
 Association (AEA).            Pilots Association
                               (AOPA).
Experimental Aircraft         General Aviation      National Air Traffic
 Association (EAA).            Manufacturers         Controllers
                               Association (GAMA).   Association
                                                     (NATCA).
RTCA........................  SAE.................
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                       International Manufacturers
------------------------------------------------------------------------
Dassault Falcon.............  Diamond.............  Flight Design.
Rotax.......................  Socata..............
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[[Page 13456]]

 
                International Civil Aviation Authorities
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European Aviation Safety      Transport Canada      National Civil
 Agency (EASA).                Civil Aviation        Aviation Agency of
                               (TCCA).               Brazil (ANAC).
Civil Aviation                Civil Aviation
 Administration of China       Authority of New
 (CAAC).                       Zealand.
------------------------------------------------------------------------

    Each member or participant on the committee represented an 
identified segment of the aviation community, with the authority to 
speak for that segment. The ARC also invited subject matter experts to 
support specialized working groups and subgroups, as necessary. These 
working groups developed recommendations and briefed the ARC as a 
whole. The ARC then collectively discussed and voted to accept or 
reject the recommendations. All of the recommendations included in the 
ARC's report had overwhelming majority agreement.
    The ARC noted the prevailing view within industry was that the only 
way to reduce the program risk, or business risk, associated with the 
certification of new airplane designs was to avoid novel design 
approaches and testing methodologies. The certification of new and 
innovative products today frequently requires the FAA's use of ELOS 
findings, special conditions, and exemptions. These take time, 
resulting in uncertainty and high project costs. The ARC emphasized 
that although industry needs from the outset to develop new airplanes 
designed to use new technology, current certification costs inhibit the 
introduction of new technology. The ARC identified prescriptive 
certification requirements as a major barrier to installing 
safety[hyphen]enhancing modifications in the existing fleet and to 
producing newer, safer airplanes.
    The ARC also examined the harmonization of certification 
requirements among the FAA and foreign civil aviation authorities 
(CAAs), and the potential for such harmonization to improve safety 
while reducing costs. Adopting performance-based safety regulations 
that facilitate international harmonization, coupled with 
internationally accepted means of compliance, could result in both 
significant cost savings and the enabling of safety-enhancing equipment 
installations. The ARC recommended that internationally accepted means 
of compliance should be reviewed and voluntarily accepted by the 
appropriate aviation authorities, in accordance with a process 
established by those authorities. Although each CAA would be capable of 
rejecting all or part of any particular means of compliance, the intent 
would be to have full civil authority participation in the creation of 
the means of compliance to ease acceptance of the means of compliance.

B. New Safety Requirements

    The performance-based standards proposed in this NPRM are designed 
to maintain the level of safety provided by current part 23 
requirements. The current part 23 weight and propulsion divisions were 
based on assumptions that do not reflect the diversity of performance 
capabilities, design complexity, technology, intended use, and seating 
capacity of today's new airplane designs, or the future airplane 
designs that will become possible as technology continues to evolve. 
The FAA would therefore replace the current divisions with 
certification levels 1 thru 4, low performance, high performance, and 
simple. Furthermore, this would replace the current divisions within 
the individual sections with technical and operational capabilities 
focused on the technical drivers (e.g., stall speed, Visual Flight 
Rules (VFR) and Instrument Flight Rules (IFR) operations, 
pressurization). These types of technical and operational criteria 
would apply a more appropriate set of standards to each airplane, and 
continue to accommodate the wide range of airplane designs within part 
23.
    To begin, the FAA proposes to eliminate commuter, utility, and 
acrobatic airplane categories from part 23, retaining only a normal 
category for all new part 23 type certificated airplane design 
approvals. The differences between normal, utility, and acrobatic 
categories are currently very limited and primarily affect airframe 
structure requirements. Proposed part 23 would continue to allow a 
normal category airplane to be approved for aerobatics, provided the 
airplane is certificated for the safety factors and defined limits of 
aerobatic operations.
    In addition, the FAA proposes that airplanes approved for spins be 
certificated to aerobatic standards. Under the current Sec.  23.3(b), 
the utility category provides airplanes additional margin for the more 
stringent inertial structural loads resulting from intended spins and 
other maneuvers. An airplane designed with traditional handling 
qualities and designed to allow spin training is more susceptible to 
inadvertent departure from controlled flight. The FAA therefore 
believes that maintaining the current utility category for spin and 
limited aerobatic maneuver capable airplanes would negate the largest, 
single safety gain expected from this rulemaking action--the 
significant reduction in inadvertent stall-related departures from 
controlled flight.
    Under this proposal, airplanes already certificated in the 
commuter, utility, and acrobatic categories would continue to fall 
within those categories. Each new airplane design, however, would be 
subject to varying levels of analysis, based on the potential risk and 
performance of the airplane's design. A more rigorous standard, such as 
currently applied to commuter category airplanes, would apply to higher 
risk and higher performance airplanes.
    The proposed requirements would also include new enhanced standards 
for resistance to departure from controlled flight. Recognizing that 
the largest number of fatal accidents for part 23 airplanes results 
from LOC in flight, the FAA proposes to update certification standards 
to address these risks. LOC happens when an airplane enters a flight 
regime outside its normal flight envelope or performance capabilities 
and develops into a stall or spin, an event that can surprise the 
pilot. A pilot's lack of awareness of the state of the airplane in 
flight and the airplane's low-speed handling characteristics are the 
main causal factors of LOC accidents. Furthermore, stall and departure 
accidents are generally fatal because an airplane is often too low to 
the ground for the pilot to recover. Improving safety that reduces 
stall and LOC accidents would save lives. The FAA is therefore 
proposing new rules for stall characteristics and stall warnings that 
would result in airplane designs more resistant to inadvertently 
departing controlled flight.
    Another type of low-speed LOC accident that occurs in significant 
numbers involves minimum control speed (VMC) in light twin-
engine airplanes. Virtually all twin-engine airplanes have a 
VMC that allows directional control to be maintained after 
one engine fails. This speed is usually above the stall speed of the 
airplane. However, light twin-engine airplanes typically have limited 
climb capability on one engine. In the accidents reviewed by the ARC 
and FAA, often in these situations, pilots attempted to maintain a 
climb or

[[Page 13457]]

maintain altitude, which slowed the airplane down, rather than looking 
for the best landing site immediately, maintaining control the whole 
way. If the airplane's speed drops below VMC, the pilot can 
lose control. In tying the minimum control speed to the stall speed of 
the airplane, pilots, rather than attempting to maintain climb and lose 
directional control, would instead react appropriately with stall 
training techniques, resulting in a controlled descent rather than a 
loss of directional control. This requirement will be on new airplanes 
and should add little or no cost because it can be designed in from the 
start.
    The FAA also has identified a need for improved certification 
standards related to operations in severe icing conditions. More 
specifically, in the 1990's, the FAA became aware of the need to expand 
the icing conditions considered during the certification of airplanes 
and turbine aircraft engines, to increase flight safety during some 
severe icing conditions. The 1994 accident in Roselawn, Indiana, 
involving an Avions de Transport Regional ATR 72 series airplane in SLD 
conditions, brought to public and governmental attention safety 
concerns about the adequacy of the existing icing certification 
standards.
    As a result of the 1994 accident, and consistent with related NTSB 
recommendations, in 1997 the Administrator tasked the Aviation 
Rulemaking Advisory Committee (ARAC) (62 FR 64621, December 8, 1997) 
with defining SLD, mixed phase, and ice crystal icing environments, and 
designing corresponding safety requirements for those conditions. In 
June 2000, the ARAC's task was revised to address only transport 
category airplanes. More recent events, such as an Air France Airbus 
model A330-203 AF447 \9\ accident, in 2009, highlighted the negative 
effects of ice crystals on airspeed indication systems and turbojet 
engines.
---------------------------------------------------------------------------

    \9\ See www.regulations.gov (Docket #FAA-2015-1621), Air France 
A330-203, Flight AF 447 Final Accident Report
---------------------------------------------------------------------------

    The FAA ultimately published amendments 25-140 (79 FR 65507, 
November 4, 2014) and 33-34 (79 FR 65507, November 4, 2014), Airplane 
and Engine Certification Requirements in Supercooled Large Drop, Mixed 
Phase, and Ice Crystal Icing Conditions that expanded parts 25 and 33 
icing requirements, but did not amend part 23 requirements. On February 
19, 2010, the Administrator chartered a Part 23 Icing ARC to review and 
recommend SLD, mixed phase, and ice crystal icing conditions 
regulations and guidance for part 23. In February 2012, the Part 23 
Icing ARC formally identified a need to improve the part 23 regulations 
to ensure safe operation of airplanes and engines in SLD and ice 
crystal conditions.\10\ In particular, the Part 23 Icing ARC 
recommended adopting most of the part 25 icing rules, including the 
requirement to show either that an airplane can safely fly in SLD 
conditions, or that it can detect and safely exit SLD. The proposals in 
this NPRM incorporate the recommendations of the Part 23 Icing ARC.
---------------------------------------------------------------------------

    \10\ See www.regulations.gov (Docket #FAA-2015-1621)
---------------------------------------------------------------------------

C. Benefits for the Existing Fleet

    The proposed revisions would benefit owners and modifiers of 
existing part 23 airplanes, as well as airplane designers and 
manufacturers. Both currently and under this proposal, airplanes may be 
modified by: (1) An alteration to an individual airplane; (2) a 
supplemental type certificate (STC) for multiple airplanes, or (3) an 
amendment to an original type design via an amended type certificate 
(TC). This proposal would streamline each of these methods for 
modifying airplanes.
    The proposed change to Sec.  21.9 would facilitate FAA approval of 
low-risk equipment produced for installation in type-certificated 
airplanes, thereby streamlining the process for owners to upgrade 
equipment on their individual airplanes. An example of how this change 
would facilitate safety improvements is the installation of inexpensive 
weather display systems in the cockpits of small airplanes. These 
systems allow a pilot to view current weather conditions along the 
planned flight route and at the destination airport, avoiding 
unexpected or deteriorating weather conditions. Since these systems are 
not required and because they represent low safety risk from failure, 
the FAA believes streamlining its approval process to produce them for 
use in existing airplanes could lower costs and increase availability 
of these systems.
    The proposed changes in the rules would also streamline the process 
for design approval holders applying for a type design change, or for a 
third party modifier applying for an STC, to incorporate new and 
improved equipment in a model or several models of airplanes. Since the 
revised part 23 standards would be much less prescriptive, the 
certification process for modifications would be simplified. 
Certification of an amended TC or STC under the proposed part 23 
standards would require fewer special conditions or exemptions, 
lowering costs and causing fewer project delays.

D. Conforming Amendments and Other Minor Amendments

    References to part 23 appear throughout the FAA's current 
regulations. Accordingly, the FAA proposes to amend the following parts 
for consistency with the proposed revisions to part 23: Part 21, part 
35, part 43, part 91, part 121, and part 135.
    The FAA also proposes to revise part 21 to simplify the approval 
process for low-risk articles. Specifically, the FAA proposes amending 
Sec.  21.9 to allow FAA-approved production of replacement and 
modification articles using methods not listed in Sec.  21.9(a). This 
proposed change is intended to reduce constraints on the use of non-
required, low risk articles, such as carbon monoxide detectors and 
weather display systems.

E. Public Policy Implementation

    The intent of this NPRM is to reduce regulatory barriers by 
establishing a system based on safety-focused performance requirements 
and FAA acceptance--as a means of compliance--of consensus standards. 
FAA-accepted consensus standards would add clarity to the certification 
process and streamline FAA involvement in the development of means of 
compliance. Additionally, adopting performance standards would 
significantly reduce the complexity of part 23. Furthermore, the 
introduction of airplane certification levels based on risk (i.e., 
number of passengers) and performance (i.e., speed) would advance the 
FAA's effort to introduce risk-based decision-making and better align 
with the FAA's safety continuum philosophy. Together, the FAA believes 
these changes would allow the FAA to provide appropriate oversight 
based on the safety continuum and would restore a simple and cost 
effective certification process based on proven engineering practices.
1. Regulatory Planning and Review
    In accordance with applicable executive orders, the FAA has 
determined that the proposed revisions to part 23 are the most cost-
beneficial way of achieving the agency's regulatory objectives. This is 
because the proposal would relieve industry of a significant regulatory 
burden while maintaining or improving the level of safety under the 
regulations. In particular, Executive Order 12866, Regulatory Planning 
and Review (58 FR 51735, October 4, 1993), and Executive Order 13563, 
Improving

[[Page 13458]]

Regulation and Regulatory Review (76 FR 3821, January 21, 2011), direct 
each Federal agency to propose or adopt a regulation only upon a 
reasoned determination that the benefits of the intended regulation 
justify its costs. This proposal is not an economically ``significant 
regulatory action'' as defined in section 3(f) of Executive Order 12866 
\11\ and it satisfies Executive Order 13563 by protecting public 
health, welfare, safety, while promoting economic growth, innovation, 
competitiveness, and job creation.
    Under the above-referenced executive orders, when an agency 
determines that a regulation is the best available method of achieving 
its regulatory objective, the agency must design the regulation or 
regulations in the most cost-effective manner. In doing so, each agency 
must consider incentives for innovation, consistency, predictability, 
enforcement and compliance costs (to the government, regulated 
entities, and the public), flexibility, distributive impacts, and 
equity. Each agency must identify and assess alternative forms of 
regulation and shall specify, to the extent feasible, performance 
objectives, rather than specifying the behavior or manner of compliance 
that regulated entities must adopt. This proposal meets these 
requirements because it would implement performance objectives rather 
than a prescriptive methodology, thereby reducing time and cost burdens 
on industry and increasing opportunities for innovation.
    Executive Order 13610, Identifying and Reducing Regulatory Burdens 
(77 FR 28469, May 10, 2012) reiterates the direction from Executive 
Order 13563 in stating that our regulatory system must measure, and 
seek to improve, the actual results of regulatory requirements. To 
promote this goal, agencies are to engage in periodic review of 
existing regulations, and are required to develop retrospective review 
plans to examine existing regulations in order to determine whether any 
such regulations should be modified, streamlined, expanded, or 
repealed. The purpose of this requirement is to make the agency's 
regulatory program more effective or less burdensome in achieving the 
regulatory objectives. In response to Executive Orders13563 and 13610, 
agencies have developed and made available for public comment 
retrospective review plans. Both the Part 23 Reorganization ARC and 
this Part 23 Rulemaking Project are on the Department of 
Transportation's retrospective review plans.
2. Consensus Standards
    Section 3(c) of SARA requires the Administrator, when developing 
regulations, to comply with the requirements of the National Technology 
Transfer and Advancement Act of 1995 \12\ (Pub. L. 104-113; 15 U.S.C. 
272 note) (NTTAA) and to use consensus standards to the extent 
practicable while maintaining traditional methods for meeting part 23. 
Section 12(d) of the NTTAA directs Federal agencies to use, either by 
reference or by inclusion, voluntary consensus standards in lieu of 
government-mandated standards, except where inconsistent with law or 
otherwise impractical. The Office of Management and Budget (OMB) 
Circular A-119,\13\ Federal Participation in the Development and Use of 
Voluntary Consensus Standards and Conformity Assessment Activities, 
provides guidance to Executive agencies in implementing the 
requirements of the NTTAA.
---------------------------------------------------------------------------

    \12\ http://www.gpo.gov/fdsys/pkg/PLAW-104publ113/pdf/PLAW-104publ113.pdf.
    \13\ https://www.whitehouse.gov/omb/circulars_a119/.
---------------------------------------------------------------------------

    Accordingly, the FAA proposes to accept consensus standards as a 
means of compliance with the proposed part 23 performance-based 
regulations. The use of consensus standards would be one means of 
compliance with the performance-based standards of the proposed part 
23. Compliance with the current prescriptive provisions within current 
part 23 would be yet another means of compliance available under this 
proposal. Applicants would still have the option to propose their own 
means of compliance as they do today. The process for reviewing new 
means of compliance would not change substantially from the process in 
place today.
    Although a consensus standard works in some cases, the Part 23 
Reorganization ARC expressed concerns that a consensus standard could 
be biased in favor of a few large manufacturers and thereby create an 
unfair competitive advantage. OMB Circular A-119 also cautions 
regulators to avoid such potential biases. The FAA notes that industry 
groups associated with the Part 23 Reorganization ARC identified ASTM 
International (ASTM) as the appropriate organization to initiate the 
development of consensus standards, and that ASTM permits any 
interested party to participate in the committees developing consensus 
standards. The FAA expects other consensus standards bodies to allow 
similar opportunities for interested parties to participate in their 
standards-development work. In addition to consensus standards and the 
current prescriptive design standards in part 23, any individual or 
organization may develop its own proposed means of compliance that may 
be submitted to the FAA for acceptance.
3. International Cooperation Efforts for Reorganizing Part 23
    Executive Order 13609, Promoting International Regulatory 
Cooperation (77 FR 26413, May 4, 2012), promotes international 
regulatory cooperation to meet shared challenges and reduce, eliminate, 
or prevent unnecessary differences in regulatory requirements. 
Consistent with this Order, the FAA's proposal would address 
unnecessary differences in regulatory requirements between the United 
States and its major trading partners. The U.S. GA industry has 
repeatedly informed the FAA of the high costs to address differences 
between the airworthiness requirements of the FAA and foreign CAAs. The 
FAA believes this proposal has the potential to achieve long-term 
harmonization at an unprecedented level, and should result in a 
significant savings for both U.S. manufacturers exporting products 
abroad and foreign manufacturers exporting products to the U.S. The FAA 
requests comments regarding the potential cost savings.
    The work of the Part 23 Reorganization ARC forms the foundation of 
the proposed changes to part 23. From the onset, the ARC was a 
cooperative, international effort. Representatives from several foreign 
CAAs \14\ and international members from almost every GA manufacturer 
of airplanes and avionics participated in the Part 23 Reorganization 
ARC. Several international light-sport aircraft manufacturers, who were 
interested in certificating their products using part 23 airworthiness 
standards, also participated. In addition to recommending changes to 
part 23, the ARC developed proposals to help reduce certification costs 
through more international standardization of certification processes 
and reducing or eliminating redundant certification activities 
associated with foreign certification.
---------------------------------------------------------------------------

    \14\ CAAs included participants from Brazil, Canada, China, 
Europe, and New Zealand.
---------------------------------------------------------------------------

    After the ARC issued its report, the FAA, foreign CAAs, and 
industry continued to work together to refine the ARC rule language 
until the FAA began drafting the NPRM in December 2014. This included 
formal meetings in July and November of 2014. EASA,

[[Page 13459]]

Transport Canada, other foreign authorities, and industry offered 
significant contributions to these efforts.
    In addition, the CAAs from Europe, Canada, Brazil, China, and New 
Zealand are working to produce rules similar to those contained in this 
proposal. EASA, for example, published an Advance Notice of Proposed 
Amendment (A-NPA) 2015-06 on March 27, 2015, which sets forth EASA's 
concept for its proposed reorganization of CS-23, and on which the FAA 
provided comments. Like the FAA's current proposal, EASA's A-NPA was 
also based on the proposed ARC language with the goal of harmonization. 
Both proposals would adopt performance-based standards that facilitate 
the use of consensus standards as a means of compliance.

F. Means of Compliance

    This proposal would allow type certificate applicants to use FAA-
accepted means of compliance to streamline the certification process. 
This proposal, however, is shaped by two concerns raised in the Part 23 
Reorganization ARC. First, the rule needs to clearly state that any 
applicant must use a means of compliance accepted by the Administrator 
when showing compliance with part 23. The FAA emphasizes that any means 
of compliance would require FAA review and acceptance by the 
Administrator. Second, although a means of compliance developed by a 
consensus standards body (i.e., ASTM, SAE, RTCA, etc.) may be 
available, any individual or organization would also be able to submit 
its own means of compliance documentation to the Administrator for 
consideration and potential acceptance.
    The FAA anticipates that both individuals and organizations would 
develop acceptable means of complying with the proposed performance 
standards. The industry groups associated with the ARC discussed the 
development of consensus-based standards and selected ASTM as the 
appropriate organization to initiate the effort. A standards 
organization such as ASTM could, for example, generate a series of 
consensus-based standards for review, acceptance, and public notice of 
acceptance by the FAA. The ASTM standards would be one way, but not the 
only way, to demonstrate compliance with part 23.
    Using means of compliance documents to satisfy compliance with the 
proposed performance-based rules would diminish the need for special 
conditions, ELOS findings, and exemptions to address new technology 
advancements. Once the Administrator accepted a means of compliance, it 
could be used in future certification applications unless formally 
rescinded. Incorporating the use of consensus standards as a means of 
compliance with performance-based regulations would provide the FAA 
with the agility to more rapidly accept new technology as it develops, 
leverage industry experience and expectations to develop of new means 
of compliance documents, and encourage the use of harmonized means of 
compliance among the FAA, industry, and foreign CAAs. Although an 
applicant would not be required to use previously accepted means of 
compliance documents, doing so would streamline the certification 
process by eliminating the need for the FAA to develop an issue paper 
to address the certification of new technology. Proposed Advisory 
Circular 23.10, Accepted Means of Compliance, would describe a process 
for applicants to submit proposed means of compliance to the FAA for 
acceptance by the Administrator.
    The Part 23 Reorganization ARC was also concerned that specialists 
in the industry could argue for complex means of compliance when the 
FAA would accept a simpler or more cost effective approach. To address 
these concerns, the FAA would continue to allow applicants to propose 
their own means of compliance when the larger industry standard may be 
the appropriate level of safety for one but not all certification 
levels, consistent with the guidance in OMB Circular A-119, which 
reminds the regulator that the government is responsible to the public 
for setting the appropriate level of safety and avoiding any unfair 
competitive advantage. Additionally, the FAA proposes to continue to 
allow the use of the prescriptive means of compliance currently 
codified in part 23 as yet another alternative means of compliance with 
proposed part 23. This would not apply, however, to the proposed new 
requirements, such as Sec. Sec.  23.200, 23.215, and 23.230.

G. FAA Strategic Initiatives

    The FAA's Strategic Initiatives 2014-2018 communicates FAA goals 
for addressing the challenges presented by the changing aviation 
industry and how the FAA intends to make the U.S. aviation system safer 
and smarter, and raise the bar on safety. Specifically, one strategic 
initiative is for the FAA to embrace and implement risk-based decision 
making approaches, which build on safety management principles to 
address emerging safety risks using consistent, data-informed 
approaches to make smarter, quicker system-level decisions. By 
establishing performance-based regulations, coupled with industry 
standards, this proposed rulemaking would provide a calibrated and 
globally competitive regulatory structure. This new approach would 
increase safety in general aviation by enabling and facilitating 
innovation and the implementation of safety enhancing designs in newly 
certificated products.
    This rulemaking effort also directly supports the FAA's Global 
Leadership Initiative, by encouraging global harmonization and the 
consistent use of regulations, standards, and practices for general 
aviation airplanes.

IV. Discussion of Proposal

A. Reorganization of Airworthiness Standards Based on Risk and 
Performance

    The FAA proposes replacing the current weight and propulsion-based 
airplane certification divisions with airplane certification and 
performance levels based on the number of potential passengers and the 
performance of the airplane. The FAA believes this proposed regulatory 
change would better accommodate the wide range of airplanes 
certificated under part 23, thereby reducing certification risk, time, 
and costs.
    Historically, turbine-powered airplanes were assumed to fly at or 
above 18,000 feet (5,486 meters) and at high speeds, whereas piston 
engine airplanes were assumed to fly below 18,000 feet (5,486 meters) 
and at lower speeds. Today, with advancements in aviation technology, 
these general design and performance assumptions may not be valid. 
Furthermore, the current regulations do not account for airplanes 
equipped with new technologies, such as electric propulsion systems, 
which may have features that are entirely different from piston and 
turbine engines. For these reasons, the FAA is proposing regulations 
based on airplane performance and potential risk rather than on 
assumptions about specific technologies. These proposed standards would 
be appropriate to each specific airplane design.
    Certification of airplanes under part 23 would either be conducted 
using airplane certification levels based on maximum passenger seating 
configuration and airplane performance levels based on speed, or occur 
as so-called ``simple airplanes'' that are low-speed airplanes with a 
stalling speed (VSO) <= 45 Knots Calibrated Airspeed (KCAS) 
approved only for VFR operations. The FAA proposes the following 
airplane certification levels:


[[Page 13460]]


     Level 1--for airplanes with a maximum seating 
configuration of 0 to 1 passengers, including simple airplanes.
     Level 2--for airplanes with a maximum seating 
configuration of 2 to 6 passengers.
     Level 3--for airplanes with a maximum seating 
configuration of 7 to 9 passengers.
     Level 4--for airplanes with a maximum seating 
configuration of 10 to 19 passengers.

B. Introduction of Simple Airplanes

    The regulations contained in part 23 have gradually become more 
focused on high-performance, turbine-powered airplanes, and this 
emphasis has become a barrier to the efficient certification and 
introduction to market of new entry-level, simple airplanes. The Part 
23 Reorganization ARC specifically noted that current part 23 does not 
have appropriate standards for the certification of entry-level 
airplanes.
    The FAA proposes to define ``simple airplanes'' in Sec.  23.5 to 
recognize the entry-level airplane. Simple airplanes would be limited 
to airplane designs that allow transport of no more than one passenger 
(in addition to the pilot), are limited to VFR operations, and have 
both a low top speed and a low stall speed. These airplanes are similar 
to EASA's Certification Specification--Very Light Aeroplanes (CS-VLA), 
which are currently imported to the U.S. and certificated as special 
class airplanes in accordance with 14 CFR 21.17(b). The proposed change 
would allow these airplanes to be certified as normal category 
airplanes under part 23.
    The FAA believes that permitting certification of simple airplanes 
would allow more certified entry-level airplanes to enter the 
marketplace. The FAA expects simple airplanes to be a more basic 
sublevel within proposed certification level 1, but recognizes that 
because of similarities between simple and non-simple airplanes within 
certification level 1, creating this category may be unnecessary. For 
this reason, the FAA is specifically asking for comments concerning the 
utility of creating a separate, simple airplane sublevel.

C. Establishing Performance-Based Standards and the Use of Means of 
Compliance

    The Part 23 Reorganization ARC was aware the Administrator has 
accepted as evidence of compliance various manufacturers' internal 
design standards in the past, and the ARC recommended expressly stating 
that option in the proposal. Proposed Sec.  23.10, Accepted Means of 
Compliance, would allow individual persons or companies to submit their 
internal standards as means of compliance for consideration by the 
Administrator. Proposed Sec.  23.10 would also require an applicant to 
show the FAA how it would demonstrate compliance with this part using a 
means of compliance, which may include consensus standards accepted by 
the Administrator. It would further require an applicant requesting 
acceptance of a means of compliance to provide the means of compliance 
to the FAA in a form and manner specified by the Administrator. In 
addition, proposed Sec.  23.10 specifically recognizes the use of 
consensus standards as a means of compliance that could be acceptable 
to the Administrator. If this information is proprietary in nature, it 
would be afforded the same protections as are applied today in 
certification applications submitted under 14 CFR part 21.
    The phrase ``means of compliance'' may have different connotations 
depending on its context. Historically, the FAA has treated an 
applicant's demonstration of compliance as a means of compliance. 
Alternatively, as indicated by sec. 3(b)(4) of the SARA, consensus 
standards may constitute a means of compliance that can address new and 
novel designs and technologies. In other words, as suggested by the 
SARA, an applicant would develop a design to satisfy a performance-
based standard, and the design is the means of complying with the 
standard.
    Currently, an applicant for a type certificate must show the FAA 
how it satisfies the applicable airworthiness standards. The applicant 
submits the type design, test reports, and computations necessary to 
show compliance. The applicant approaches the FAA and enters into 
negotiations regarding what constitutes an adequate demonstration--
testing or analysis. The FAA anticipates that, under the proposed 
framework, standards developed by consensus standards bodies would 
provide a pre-existing means by which any applicant may demonstrate 
compliance with the corresponding performance-based requirements. For 
example, the proposed fuel system requirements would be broad enough to 
certificate airplanes with electric propulsion systems in which 
batteries and fuel cells are used as fuel. Airplanes incorporating 
these systems cannot currently be certificated without applying for 
special conditions or exemptions.
    Elements of this proposal are already in place today. Industry 
standards bodies like RTCA, SAE, ASTM, and the European Organization 
for Civil Aviation Equipment (EUROCAE) have already developed detailed 
means of compliance documents that an applicant for a type certificate 
may use to demonstrate compliance with our regulatory requirements in 
14 CFR parts 23, 25, 27, and 29. For decades, the FAA has identified 
these means of compliance documents as an acceptable means of complying 
with our regulatory requirements. This proposal would build on and 
expand this aspect of our regulations by also transitioning part 23 
towards a regulatory framework based on performance standards.

D. Crashworthiness as an Illustration of the Benefits of Performance-
Based Regulations

    One area where the implications of a change from prescriptive to 
performance-based requirements are most evident is in the demonstration 
of crashworthiness. The current part 23 crashworthiness and occupant 
safety requirements are based on seat and restraint technology used in 
the 1980's. Currently, an applicant demonstrates crashworthiness by a 
sled test. Under the proposed standards, an applicant would not 
necessarily have to perform a sled test, but could instead employ a 
different method accounting for many other factors, several of which 
are described below. The FAA is imposing no new requirements, but 
would, under this proposal, provide greater flexibility to adopt new 
safety-testing methodologies and, ultimately, more advanced safety 
technologies.
    The FAA proposes to allow greater flexibility with respect to the 
testing and demonstration, similar to advancements made in the 
automotive industry over the past 30 years. The proposed regulations 
would facilitate evaluation of the entirety of a crashworthiness 
system--namely, the interaction of all crashworthiness features--rather 
than requiring an evaluation of discrete, individual parameters. A 
system's ability to protect occupants can be better understood by 
evaluating it as a complete system, and using that greater 
understanding to develop and implement new technologies. Such an 
evaluation could include analyses of important survivability factors 
identified by the NTSB, including occupant restraints, survivable 
volume, energy-absorbing seats, and seat retention. These proposed 
crashworthiness standards would not necessarily prevent accidents, but 
should improve survivability.
    The NTSB produced a series of reports in the 1980s that evaluated 
over 21,000 GA airplane crashes between 1972 and 1981. The NTSB General

[[Page 13461]]

Aviation Crashworthiness Project \15\ evaluated airplane orientation, 
impact magnitudes, and survival rates and factors to provide 
information supporting changes in crashworthiness design standards for 
GA seating and restraint systems. The NTSB reports also established 
conditions approximating survivable accidents and identified factors 
that would have the largest impact on safety. Amendment 23-36 (53 FR 
30802, August 15, 1988) to part 23 referenced these reports for dynamic 
seats but did not adopt a systems-evaluation approach.
---------------------------------------------------------------------------

    \15\ See www.regulations.gov (Docket # FAA-2015-1621).
---------------------------------------------------------------------------

    The NTSB reports identified several factors that, working together 
as a system, should result in a safer airplane. The assessment also 
indicated, however, that shoulder harnesses offer the most immediate 
individual improvement for safety. The FAA codified the shoulder 
harnesses requirement in amendments 23-19 (42 FR 20601, June 16, 1977) 
and 23-32 (50 FR 46872, November 13, 1985) for newly manufactured 
airplanes. The FAA also issued policy statement ACE-00-23.561-01, 
Methods of Approval of Retrofit Shoulder Harness Installations in Small 
Airplanes,\16\ dated September 19, 2000, to streamline the process for 
retrofitting older airplanes. Current part 23 requires occupant 
restraints to maintain integrity, stay in place on the occupant 
throughout an event, properly distribute loads on the occupant, and 
restrain the occupant by mitigating interaction with other items in the 
cabin. Newer technologies that enhance or supplement the performance of 
these restraints, such as airbags, are now being considered for 
inclusion in designs. The use of airbags has greatly increased 
passenger safety in automobiles, by offering protection in much more 
severe impacts and in impacts from multiple directions. The proposed 
performance standards would enable the use of these technologies.
---------------------------------------------------------------------------

    \16\ See www.regulations.gov (Docket # FAA-2015-1621).
---------------------------------------------------------------------------

    Survivable volume is another critical factor in crashworthiness. 
Survivable volume is the ability of the airframe to protect the 
occupants from external intrusion, or the airplane cabin crushing 
during and after an accident. There were several observed accidents in 
the NTSB study where conventional airplane construction simply crushed 
an otherwise restrained occupant. Crashworthiness regulations have 
never included survivable volume as a factor, except in some instances 
in which an airplane turns over. Airplane designs should provide the 
space needed for the protection and restraint of the occupants. This is 
one of the first steps in the analysis of airplane crashworthiness.
    Data from the NTSB General Aviation Crashworthiness Project 
suggested that energy-absorbing seats that protect the occupant from 
vertical impact loads could enhance occupant survivability and prevent 
serious injury, thereby enhancing odds for exiting the airplane and 
preventing many debilitating long-term injuries. The FAA established 
dynamic seat testing requirements in amendment 23-36 for airplanes 
certificated under part 23. Energy absorbing seats have a smaller 
impact than some other safety factors because accident impacts with 
large vertical components tend to have lower odds of survival. 
Nevertheless, energy attenuation from vertical forces, both static and 
dynamic, has been important to crashworthiness regulations for the past 
25 years. Seats may crush or collapse, but must remain attached to the 
body of the airplane. Coupling the seat performance to the rest of the 
airframe response is important to the enhancement and understanding of 
occupant survivability. The FAA believes allowing designers to consider 
airframe deformation would result in more accurate floor impulses, 
which relate to simulated crash impact, and may allow for evaluation 
for crash impulses in multiple directions.
    The NTSB also identified seat retention as another basic building 
block for airplane crashworthiness. The NTSB reports show more than a 
quarter of otherwise-survivable accidents included instances where the 
seats broke free at the attachment to the airplane, resulting in 
fatalities or serious injuries. Dynamic seat testing requirements 
address the ability of seat assemblies to remain attached to the floor, 
even when the floor shifts during impact. Pitching and yawing of the 
seat tracks during dynamic seat tests demonstrates the gimbaling and 
flexibility of the seat.
    The FAA believes that, under this proposal, all of these 
crashworthiness factors could be incorporated into future testing 
methodologies and thereby increase the survivability of accidents in 
part 23 certificated airplanes. This proposed part 23 amendment would 
authorize design approval applicants to use these technologies and 
testing methodologies to enhance occupant safety.

E. Additional Requirements To Prevent LOC

    LOC continues to be the leading cause of fatal GA accidents. The 
FAA identified 74 accidents caused by stall or LOC between January 2008 
and December 2013. These accidents, which are listed in Appendix IV of 
the Part 23 Regulatory Evaluation,\17\ represent the type of accidents 
that could be prevented by the proposed new stall and LOC requirements.
---------------------------------------------------------------------------

    \17\ See www.regulations.gov (Docket # FAA-2015-1621).
---------------------------------------------------------------------------

    The FAA proposes to add requirements in Sec. Sec.  23.200 and 
23.215 to prevent LOC accidents. Inadvertent stalls resulting in 
airplane LOC cause a large number of small airplane fatal accidents. 
These LOC accidents in the traffic pattern or at low altitudes often 
result in fatalities because the airplane is too low to the ground for 
the pilot to recover control. The FAA therefore believes it can improve 
safety by requiring applicants to use new approaches to improve 
airplane stall characteristics to prevent such accidents.
    Another type of low-speed LOC accident that occurs in significant 
numbers involves VMC in light twin-engine airplanes. 
Virtually all twin-engine airplanes have a VMC that allows 
directional control to be maintained after one engine fails. This speed 
is typically above the stall speed of the airplane. However, light 
twin-engine airplanes also typically have limited climb capability on 
one engine. Moreover, after the failure of one engine, pilots often 
instinctively tend to try to maintain a climb or maintain altitude, 
which slows the airplane down. If the speed drops below VMC, 
the pilot can lose control of the airplane. Because pilots tend to be 
more aware of the airplane's stall speed, the FAA proposes in Sec.  
23.200 that certification levels 1 and 2 multiengine airplanes would be 
required to have a VMC that does not exceed the stall speed 
of the airplane for each configuration. The FAA believes this proposed 
requirement would provide a higher level of safety than current Sec.  
23.149. The FAA requests comments on this proposal.
    The FAA also proposes new requirements in Sec.  23.215 for airplane 
stall characteristics and stall warning that would result in airplane 
designs more resistant to inadvertently stalling and departing 
controlled flight. These proposed requirements would increase the level 
of safety over the current requirements. At the same time, the FAA 
proposes to eliminate the spin recovery requirement in the current 
rules for normal category airplanes. The FAA believes the spin recovery 
requirement is unnecessary for normal category airplanes because the 
vast

[[Page 13462]]

majority of inadvertent stalls leading to spin entry occur below a safe 
altitude for spin recovery. However, airplanes certificated for 
aerobatics would still have to meet spin recovery requirements.
    The FAA also proposes to address pilot stall awareness by requiring 
warnings that are more effective and by allowing new approaches to 
improve pilot awareness of stall margins. These warnings could be as 
simple as angle of attack or energy awareness presentations, or 
sophisticated envelope protection systems that add a forward force to 
the pilot's controls as the airplane speed and attitude approach stall.

F. Additional Requirements for Flight in Icing Conditions

    The FAA proposes to implement the Part 23 Icing ARC's 
recommendations in Sec. Sec.  23.230, 23.940 and 23.1405, to allow an 
applicant the option of certifying an airplane to operate in SLD icing 
conditions. To do so, an applicant would be required to meet the same 
safety standards in SLD icing conditions as currently demonstrated for 
part 23 airplanes in the icing conditions defined in appendix C to part 
25.
    Currently, the FAA does not certify part 23 airplanes to operate in 
SLD icing conditions, also known as freezing drizzle and freezing rain. 
Instead, current part 23 icing regulations require airplane 
performance, flight characteristics, systems, and engine operation to 
be demonstrated in the icing conditions defined in appendix C to part 
25, which does not contain SLD icing conditions. In 2012, prior to the 
Part 23 Reorganization ARC, the Part 23 Icing ARC recommended revising 
part 23 to include SLD icing requirements in subparts B, E, and F 
(Flight, Powerplant, and Equipment, respectively).
    If an applicant chooses not to certify an airplane in SLD icing 
conditions, proposed Sec.  23.230 would require the applicant to 
demonstrate that SLD icing conditions could be detected and safely 
exited. A means of compliance for SLD detection and exit may be found 
in FAA Advisory Circular 23.1419-2D, Certification of Part 23 Airplanes 
for Flight in Icing Conditions.\18\ The service history of airplanes 
certificated under part 23 and certified to the latest icing standards 
has shown that AC 23.1419-2D provides an adequate level of safety for 
detecting and safely exiting SLD icing conditions. Industry has 
indicated that these requirements would not impose an additional burden 
because many manufacturers have already equipped recent airplanes to 
meet the standards for detecting and exiting SLD in accordance with 
current FAA guidance. Proposed Sec.  23.230, along with proposed Sec.  
23.940, Powerplant ice protection, and Sec.  23.1405, Flight in icing 
conditions, and their respective means of compliance, address NTSB 
safety recommendations A-96-54 and A-96-56. The following table 
provides a summary of the proposed icing regulations.
---------------------------------------------------------------------------

    \18\ See www.regulations.gov (Docket # FAA-2015-1621).

                       Proposed Icing Regulations
------------------------------------------------------------------------
                                                     Airframe and system
                                                         protection,
                                                       performance and
                                                           flight
  Part 23 type certificate      Engine protection      characteristics
         limitations             (Sec.   23.940)     requirements (Sec.
                                                       Sec.   23.230,
                                                        23.1300, and
                                                          23.1405)
------------------------------------------------------------------------
Not certified for flight in   Safe in part 25, App  None, except pitot
 icing conditions.             C conditions,         heat required if
                               ground ice fog, and   airplane certified
                               falling/blowing       for flight in
                               snow.                 instrument
                                                     meteorological
                                                     conditions (IMC).
Certified for flight in       Safe in part 25, App  Safe in part 25, App
 icing conditions, but         C conditions,         C conditions. Can
 prohibited for flight in      ground ice fog, and   detect SLD and
 SLD.                          falling/blowing       safely exit.
                               snow.
Certified for flight in       Safe in part 25, App  Safe in part 25, App
 icing conditions and SLD.     C conditions,         C conditions and
                               ground ice fog, and   SLD.
                               falling/blowing
                               snow, and SLD.
------------------------------------------------------------------------

G. Production of Replacement and Modification Articles

    The Part 23 Reorganization ARC recommended simplifying 
certification requirements for non-required systems and equipment, with 
an emphasis on improvement in overall fleet safety from the prevailing 
level. In the past, the FAA has not established different production 
requirements for required and non-required equipment that may enhance 
safety, or for articles whose improper operation or failure would not 
cause a hazard. The current requirements for producing articles and 
representing those articles as suitable for installation on type-
certificated products are well suited for articles manufactured in 
accordance with a product's TC or STC, as well as for TSO and PMA 
parts. However, they may unnecessarily constrain the production of non-
required, low risk articles.
    Current standards for the production approval of these articles can 
create a barrier for their installation in the existing fleet of 
aircraft. Examples of such articles include carbon monoxide detectors, 
weather display systems, clocks, small hand-held fire extinguishers, 
and flashlights. In many cases, these articles are ``off-the-shelf'' 
products. It is frequently difficult for a person to install these 
articles on a type-certificated aircraft because the level of design 
and production details necessary for these articles to meet the 
provisions of current Sec.  21.9, as expected for more critical 
articles, are frequently unavailable.
    The FAA is therefore proposing to revise Sec.  21.9, Replacement 
and Modification Articles, to provide applicants with an alternative 
method to obtain FAA approval to produce replacement and modification 
articles. This proposed change would allow a production approval 
applicant to submit production information for a specific article, 
without requiring the producer of the article to obtain approval of the 
article's design or approval of its quality system. The FAA intends to 
use the flexibility provided by this proposal to streamline the 
approval process for non-required safety enhancing equipment and other 
articles that pose little or no risk to aircraft occupants and the 
public. The FAA requests comments on this proposal, and particularly is 
interested in comments regarding whether the proposed change would 
safely facilitate retrofit of low risk articles and whether there are 
alternative methods to address the perceived retrofit barrier.

V. Key Terms and Concepts Used in This Document

    The proposal includes a number of terms introduced into the 
regulations for the first time. These terms may be used

[[Page 13463]]

to replace existing prescriptive requirements or may explain other 
terms that have had longstanding use in the aircraft certification 
process, but in context of this rulemaking proposal, the FAA wants to 
specify its meaning. These terms are intended to set forth and clarify 
the safety intent of the proposed rules. Although certain terms may 
differ from those currently in use, these differences are not intended 
to increase the regulatory burden on an applicant unless specifically 
stated. The FAA's intent is that the proposed requirements 
incorporating these new terms not change the intent, understanding, or 
implementation of the original rule unless that requirement has been 
specifically revised in the proposal, such as is the case for 
requirements governing stall characteristics. To assist applicants in 
understanding the intent of the proposal, these terms are discussed 
below:
    Airplane Certification Level--A division used for the certification 
of airplanes that is associated directly with the number of passengers 
on the airplane. Airplane certification levels would be established to 
implement the agency's concept of certificating airplanes using a 
process that recognizes a safety continuum.
    Airplane Performance Level--Maximum airspeed divisions that are 
intended, along with airplane certification levels, to replace current 
weight and propulsion divisions used for the certification of 
airplanes. Current propulsion-based divisions assume that piston engine 
airplanes are slower than turbine-powered airplanes. Current weight-
based divisions assume that heavier airplanes are more complex and 
would be more likely to be used in commercial passenger carriage than 
lighter airplanes. These assumptions are no longer valid. Airplane 
certification based on performance levels would apply regulatory 
standards appropriate to airplane's performance and complexity.
    Departure Resistant--For the purposes of this NPRM, departure 
resistant refers to stall characteristics that make it very difficult 
for the airplane to depart controlled flight. Most fatal stall or spin 
accidents start below 1000 feet above ground level and do not actually 
spin, but start a yawing and rolling maneuver to enter the spin called 
a post stall gyration. In these low-altitude accidents, the airplane 
typically hits the ground before completing one turn. Therefore, the 
important safety criterion is preventing the airplane from exhibiting 
stall characteristics that could result in a departure from controlled 
flight.
    Entry-Level Airplane--A two or four-place airplane typically used 
for training, rental, and by flying clubs. Historically, most of these 
airplanes have four cylinder engines with less than 200 horsepower. 
These airplanes typically have fixed-gear and fixed-pitch propellers, 
but may also have retractable landing gear and constant speed 
propellers. Entry-level airplanes typically cannot be used to train 
pilots to meet the requirements to operate a complex aircraft, as that 
term is defined for airman certification purposes.
    Equivalent Level of Safety (ELOS) Finding--A finding made by the 
accountable aircraft certification directorate when literal compliance 
with a certification requirement cannot be shown and compensating 
factors in the design can be shown to provide a level of safety 
equivalent to that established by the applicable airworthiness 
standard.
    Fuel--Any source used by the powerplant to generate its power.
    Hazard--Any existing or potential condition that can lead to 
injury, illness or death; damage to or loss of a system, equipment, or 
property; or damage to the environment. A hazard is a condition that is 
a prerequisite to an accident or an incident. (Cf. Order VS 8000.367, 
Appendix A)
    Issue Paper--A structured means for describing and tracking the 
resolution of significant technical, regulatory, and administrative 
issues that occur during a certification project. The issue paper 
process constitutes a formal communication vehicle for addressing 
significant issues among an applicant, the FAA, and if applicable, the 
validating authority (VA) or certificating authority (CA) for type 
validation programs. An issue paper may also be used to address novel 
or controversial technical issues.
    Means of Compliance--A documented procedure used by an applicant to 
demonstrate compliance to a performance or outcome-based standard. 
Similar to an Advisory Circular (AC), a means of compliance is one 
method, but not the only method, to show compliance with a regulatory 
requirement. Additionally, if a procedure is used as a means of 
compliance, it must be followed completely to maintain the integrity of 
the means of compliance.
    Performance- or Outcome-Based Standard--A standard that states 
requirements in terms of required results, but does not prescribe any 
specific method for achieving the required results. A performance-based 
standard may define the functional requirements for an item, 
operational requirements, or interface and interchangeability 
characteristics.
    Pilot or Flightcrew--This is used generically throughout the 
proposed part 23 because part 23 has airplanes approved for single 
pilot operations as well as and two flightcrew members. For most 
airplanes certificated under part 23 that are single pilot, applicants 
should consider pilot and flightcrew to be interchangeable.
    Prescriptive Design Standard--Specifies a particular design 
requirement, such as materials to be used, how to perform a test, or 
how an item is to be fabricated or constructed. (Cf. OMB Circular A-119 
Section 5.f.)
    Safety Continuum--The concept that one level of safety is not 
appropriate for all aviation activities. Accordingly, higher levels of 
risk, with corresponding requirements for less rigorous safety 
demonstrations for products, are accepted as aircraft are utilized for 
more personal forms of transportation.
    Survivable Volume--The airplane cabin's ability to resist external 
intrusion or structural collapse during and after impact. The ability 
to resist is usually represented as a stiffer design around the cabin 
(not unlike a racecar roll cage) that is generally stronger than the 
surrounding structure. While the airframe may deform or disintegrate 
and attenuate impact energy, the cabin of the airplane will still 
maintain its integrity and protect the occupants restrained within. 
During otherwise survivable accident scenarios, including rollover, 
this structure should maintain its shape under static and dynamic 
loading conditions.

VI. Discussion of the Proposed Regulatory Amendments

A. Part 23, Airworthiness Standards

1. Subpart A--General
a. General Discussion
    The FAA proposes eliminating the utility, acrobatic, and commuter 
categories for future airplanes certificated under part 23. The FAA 
also proposes to change from weight and propulsion divisions to 
performance and risk divisions. This would address the wide range of 
airplanes to be certificated under part 23 and enhance application of 
the safety continuum approach. Appendix 1 of this preamble contains a 
cross-reference table detailing how the current regulations are 
addressed in the proposed part 23 regulations.

[[Page 13464]]

b. Specific Discussion of Changes
i. Proposed Sec.  23.1, Applicability and Definition
    Proposed Sec.  23.1 would prescribe airworthiness standards for the 
issuance of type certificates, and changes to those certificates, for 
airplanes in the normal category. Current Sec.  23.3, Airplane 
categories, defines normal category as airplanes that have a seating 
configuration, excluding pilot seats, of nine or less, a maximum 
certificated takeoff weight of 12,500 pounds or less, and intended for 
nonacrobatic operation. Proposed Sec.  23.1 would delete references to 
utility, acrobatic, and commuter category airplanes, and paragraph (b) 
would not include the current reference to procedural requirements for 
showing compliance. The reference to procedural requirements for 
showing compliance is redundant with the requirement in Sec.  21.21, 
Issue of type certificate: Normal, utility, acrobatic, commuter, and 
transport category aircraft; manned free balloons; special classes of 
aircraft; aircraft engines; propellers, to show compliance. Proposed 
Sec.  23.1 would also add three definitions specific to part 23: (1) 
Continued safe flight and landing, (2) designated fire zone, and (3) 
empty weight.
ii. Proposed Sec.  23.5, Certification of Normal Category Airplanes
    Proposed Sec.  23.5 would apply certification in the normal 
category to airplanes with a passenger-seating configuration of 19 or 
less and a maximum certificated takeoff weight of 19,000 pounds or 
less. Proposed Sec.  23.5 would also establish certification levels 
based on the passenger seating configuration and airplane performance 
levels based on speed.
    The diversity of airplanes certificated under part 23 is large 
relative to performance, numbers of passengers, complexity, technology, 
and intended use. Airplane certification requirements under part 23 are 
currently determined using a combination of weight, numbers of 
passengers, and propulsion type. These divisions historically were 
appropriate because there was a clear relationship between the 
propulsion and weight of the airplane and its associated performance 
and complexity. Recent technological developments have altered the 
dynamics of this relationship. High-performance and complex airplanes 
now exist within the weight range that was typical for light and simple 
airplanes. Furthermore, current part 23 has evolved to meet the 
additional regulatory requirements resulting from the introduction of 
high-performance airplanes. This has resulted in the introduction of 
more stringent and demanding requirements in the lower weight airplanes 
such as the use of 14 CFR part 25 based requirements for simple, 
single-engine turbine airplanes. The result is that some of the current 
requirements have become more demanding for simple and low-performance 
airplanes.
    The FAA proposes replacing the current part 23 weight and 
propulsion divisions because they were based on assumptions that do not 
always fit the large diversity of airplane performance, complexity, 
technology, intended use, and seating capacity encompassed in today's 
new airplane designs. Also, the current divisions may not be 
appropriate to address unforeseen designs of the future. The commuter 
category, originally intended for the certification of airplanes over 
12,500 pounds and up to 19 passengers, is currently used for larger 
business jets with less than ten passengers. The proposed certification 
and performance level approach, while different from the current 
divisions, would capture the safety intent of part 23 more 
appropriately than the current propulsion and weight divisions.
    The FAA proposes replacing the current divisions with specific 
technical and operational capabilities by addressing, for example, 
stall speed, VFR/IFR operation, pressurization, etc., that represent 
the actual technical drivers for current prescriptive requirements. 
These types of design specific technical and operational criteria would 
be more appropriate for a means of compliance document where a complete 
range of airplane designs could be addressed. The FAA proposes that 
high-speed, multiengine airplanes and multiengine airplanes over 12,500 
pounds should continue meeting the equivalent commuter category 
performance-based requirements. The proposed performance requirements 
would be based on number of passengers (certification level) and 
airplane performance (performance level); not weight or propulsion 
type.
    The FAA proposes to eliminate commuter, utility, and acrobatic 
airplane categories in part 23, retaining only normal category for all 
new part 23 type certificated airplane design approvals. The FAA 
believes this action would not affect the existing fleet of small 
airplanes. For example, the commuter category was originally introduced 
into part 23 to apply to a 10 to 19 passenger, multiengine airplane, 
operated in scheduled service under 14 CFR parts 121 and 135. However, 
new airplanes certified under part 23 can no longer be used in 
scheduled service under part 121 because Sec.  121.157, Aircraft 
certification and equipment requirements, paragraph (h), requires a 
part 25 certification for newly type certificated airplanes. The 
majority of airplanes recently certified in the commuter category are 
multiengine business jets. Additionally, the certification category of 
commuter can be confused with the same term in the operating rules 
because the term is defined differently in the certification and 
operation rules. The FAA recognizes that moving away from weight and 
propulsion divisions would result in changes for the criteria used to 
determine when to apply the existing commuter category certification 
requirements using the numbers of passenger seats (excluding crewmember 
seats), performance, and technical divisions proposed in this NPRM. The 
FAA proposes the following airplane certification levels:

     Level 1--for airplanes with a maximum seating 
configuration of 0 to 1 passengers.
     Level 2--for airplanes with a maximum seating 
configuration of 2 to 6 passengers.
     Level 3--for airplanes with a maximum seating 
configuration of 7 to 9 passengers.
     Level 4--for airplanes with a maximum seating 
configuration of 10 to 19 passengers.

    The differences between normal, utility, and acrobatic categories 
are currently very limited and primarily affect airframe structure 
requirements. Proposed part 23 would still allow a normal category 
airplane to be approved for aerobatics provided the airplane was 
certified to address the factors affecting safety for the defined 
limits for that kind of operation. Currently, the utility category 
provides airplanes additional margin for the more stringent inertial 
structural loads resulting from intended spins and the additional 
maneuvers stated in the requirements of the utility category in Sec.  
23.3(b). The FAA proposes that airplanes approved for spins be 
certificated to aerobatic standards. An airplane designed with 
traditional handling qualities and designed to allow spin training is 
more susceptible to inadvertent departure from controlled flight. The 
FAA believes that maintaining the current utility category for 
airplanes approved for spins and limited aerobatic maneuvers would 
negate the single largest safety gain expected from this rulemaking 
action--the significant reduction in inadvertent stall-related 
departures from controlled flight.
    Proposed Sec.  23.5(c) would categorize the performance level of an 
airplane as low speed or high speed. The combination of certification 
levels and performance levels is intended to

[[Page 13465]]

provide divisions that address the actual safety concern of occupant 
numbers and performance, for example, future designs using novel 
propulsion methods. The FAA proposes the following airplane performance 
levels:

     Low speed--for airplanes with a design cruising speed 
(VC) or maximum operating limit speed (VMO) <= 
250 KCAS (or MMO <= 0.6).
     High speed--for airplanes with a VC or 
VMO > 250 KCAS (or MMO > 0.6).

    Proposed Sec.  23.5(d) would identify a simple airplane as one with 
a certification level 1, a VC or VMO <= 250 KCAS 
(and MMO <= 0.6), and a VSO <= 45 KCAS, and 
approved only for VFR operations. The FAA proposes a simple airplane as 
equivalent to airplanes certificated under EASA's current CS-VLA. In 
most cases, EASA's CS-VLA requirements are identical to the proposed 
corresponding part 23 requirements and have been proposed in the 
requirements for certification level 1 airplanes. The FAA considered 
using the CS-VLA standards in combination with the proposed part 23 
certification standards for all certification level 1, low-speed 
airplanes. However, the FAA believes that there are several 
requirements in CS-VLA that are not appropriate for all certification 
level 1, low-speed airplanes, such as no requirement for a type 
certified engine in CS-VLA. Therefore, the FAA proposes creating a 
limited certification and performance level for simple airplanes. 
Simple airplanes would be a subset of certification level 1, low-speed 
airplanes and would have a VSO <= 45 KCAS and would only be 
approved for VFR operations.
    In accordance with the FAA's objective to remove weight and 
propulsion divisions from the rules and use performance and 
certification divisions, the proposed requirements applicable to the 
certification of simple airplanes would not completely conform to the 
criteria EASA uses to certificate very light airplanes. The FAA 
proposes that simple airplanes would constitute a subset of 
certification level 1, low-speed airplanes that would be required to 
have a low stall speed limit and a VFR limitation in order to maintain 
a level of safety appropriate for these airplanes. The FAA believes 
that creating the simple certification level would encourage 
manufacturers of light-sport and experimental aircraft kits to pursue 
type certificates for their airplane designs without encountering the 
administrative, procedural or regulatory barriers existing in current 
part 23, while allowing innovative technology in those designs.
    The FAA considered allowing airplanes that meet the consensus 
standards applicable to the certification of special light-sport 
aircraft to be included in proposed part 23. However, the FAA decided 
that this would not be in the best interest of the GA community because 
it could result in the elimination of the special light-sport aircraft 
category. There are advantages in the certification of special light-
sport aircraft, such as self-certification, that would not be available 
if the aircraft were type certificated under part 23. This proposal 
would instead enable a simpler path to part 23 certification for 
airplanes that meet the definition of a light-sport aircraft and wish 
to pursue a type of certificate for business reasons.
    The FAA expects simple airplanes to be more basic than the proposed 
certification level 1, low-speed airplanes. A simple airplane is a 
certification level 1, low-speed airplane with a stall speed limit of 
45 KCAS that would be limited to VFR operations. The FAA recognizes 
that a simple airplane level would have characteristics very similar to 
certification level 1, low-speed airplanes, and that creating this 
category may be unnecessary. For this reason, the FAA is specifically 
asking for comments concerning the value of creating a separate, simple 
airplane level.
iii. Proposed Sec.  23.10, Accepted Means of Compliance
    Proposed Sec.  23.10 would require an applicant to show the FAA how 
it would demonstrate compliance with this part using a means of 
compliance, which may include consensus standards, accepted by the 
Administrator. Proposed Sec.  23.10 would also require an applicant 
requesting acceptance of a means of compliance to provide the means of 
compliance to the FAA in a form and manner specified by the 
Administrator.
    Proposed Sec.  23.10 would create flexibility for applicants in 
developing means of compliance and also specifically identify consensus 
standards as a means of compliance the Administratory may find 
acceptable. The Part 23 Reorganization ARC proposed using consensus 
standards for the detailed means of compliance to the fundamental 
safety requirements in proposed part 23. As discussed in the 
International Harmonization Efforts section of this NPRM, the intent of 
this proposal is to create a regulatory architecture for part 23 that 
is agile enough to keep up with innovation. Allowing the use of 
consensus standards would accomplish this goal.
    The Part 23 Reorganization ARC recommended creating this proposed 
section to identify specifically the means of compliance documents 
developed by industry, users such as large flight schools, the 
interested public, and the FAA, that an applicant could use in 
developing a certification application. The ARC expressed two concerns 
that led to the creation of the proposed requirement. First, applicants 
need to use a means of compliance accepted by the Administrator when 
showing compliance to part 23. Second, while a consensus standards body 
(i.e., ASTM, SAE, RTCA, etc.) developed means of compliance document 
may be available, individuals or organizations may also submit their 
own means of compliance documentation to the Administrator for 
consideration and potential acceptance. Additionally, the FAA wants to 
ensure applicants understand that an applicant-developed means of 
compliance document would require FAA review and acceptance by the 
Administrator.
    The FAA anticipates that individuals or organizations would develop 
acceptable means for complying with the proposed performance standards. 
A standards organization such as ASTM, for example, could generate a 
series of consensus-based standards for review, acceptance, and public 
notice of acceptance by the FAA. The ASTM standards could be one way, 
but not the only way, to demonstrate compliance with part 23. Other 
consensus standard bodies such as RTCA and SAE are currently focused on 
developing standards for aircraft components and appliances.
    The proposed airworthiness standards would allow airplanes to be 
certificated at different airplane certification levels. For example, 
software integrity levels appropriate for a certification level 1 
airplane may not be appropriate for a certification level 4 airplane. 
Additionally, the takeoff performance of an airplane might be evaluated 
differently for an airplane intended to be certificated at different 
airplane certification levels. An applicant seeking certification of a 
certification level 1 airplane with a takeoff distance of 200 feet, for 
example, would not need to establish the takeoff distance with the same 
degree of accuracy as would an applicant seeking certification of a 
certification level 4 high-speed airplane with a takeoff distance of 
4,000 feet.
    By using means of compliance documents to show compliance with the 
proposed performance-based rules, the need for special conditions, ELOS

[[Page 13466]]

findings, and exemptions to address new technology advancements would 
diminish. Once the Administrator accepted a means of compliance, it may 
be used for future applications for certification unless formally 
rescinded. Allowing the use of consensus standards as a means of 
compliance to performance-based regulations would provide the FAA with 
the agility necessary to more rapidly accept new technology, leverage 
industry expectations in the development of new means of compliance 
documents, and provide for the use of harmonized means of compliance 
among the FAA, industry, and foreign CAAs. While an applicant would not 
be required to use previously accepted means of compliance documents, 
their use would streamline the certification process by eliminating the 
need to develop an issue paper to address the certification of new 
technology. Proposed AC 23.10,\19\ Accepted Means of Compliance, would 
provide guidance for applicants on the process applicants would follow 
to submit proposed means of compliance to the FAA for consideration by 
the Administrator.
---------------------------------------------------------------------------

    \19\ See www.regulations.gov (Docket # FAA-2015-1621).
---------------------------------------------------------------------------

    The Part 23 Reorganization ARC expressed concerns that a consensus 
standard could be biased in favor of a few large manufacturers and 
would create an unfair competitive advantage. The FAA notes that any 
interested party may participate in the ASTM committees developing 
consensus standards thereby, mitigating this concern. The FAA expects 
that other consensus standards bodies would allow similar opportunities 
for interested parties to participate in their standards development 
work. Additionally, any individual or organization could develop its 
own means of compliance and submit it to the FAA for acceptance by the 
Administrator. The other risk identified by the Part 23 Reorganization 
ARC was that specialists in the industry could argue for complex means 
of compliance when the FAA would accept a simpler or more cost 
effective approach. However, the FAA would continue to allow applicants 
to propose their own means of compliance when the larger industry 
standard may be the appropriate level of safety for one, but not all 
certification levels. Lastly, the FAA intends to continue to allow the 
use of the current prescriptive means of compliance contained in 
current part 23 requirements as one obvious alternative to showing 
compliance with proposed part 23. This would not apply to the proposed 
sections that contain new requirements, such as Sec. Sec.  23.200, 
23.215, and 23.230.
    The Part 23 Reorganization ARC also was aware the Administrator has 
accepted various manufacturers' internal standards in the past and 
recommended having that option stated in the proposal. Proposed Sec.  
23.10 would allow applicants to submit their internal standards as 
means of compliance for consideration by the Administrator.
iv. Removal of Subpart A Current Regulations
    The FAA proposes removing current Sec.  23.2, Special retroactive 
requirements, from part 23 because the operational rules currently 
address these requirements. The current retroactive rule is more 
appropriate in the operating rules. The FAA proposes amending 14 CFR 
part 91, as discussed later in the Discussion of the Proposed 
Regulatory Amendments to ensure removing the current Sec.  23.2 
requirement would not affect the existing fleet.
2. Subpart B--Flight
a. General Discussion
    The FAA proposes moving away from the current stall characteristics 
and spin testing approach to address the largest cause of fatal 
accidents in small airplanes. Proposed Sec.  23.215 in subpart B would 
omit the one turn/three second spin requirement for normal category 
airplanes, but it would increase the stall handling characteristics and 
stall warning requirements so the airplane would be substantially more 
resistant to stall-based departures than the current rules require.
    The FAA also proposes eliminating the utility, acrobatic, and 
commuter categories in part 23. Accordingly, a new airplane would have 
to be approved for aerobatic loads as the normal category, even if an 
applicant only wanted to spin the airplane. Therefore, the FAA proposes 
to restrict certification of new airplanes for dual use, which can be 
done today using both the normal and utility categories. The FAA 
believes that if the airplane can spin for spin training, then the 
airplane can inadvertently stall and depart into a spin during normal 
operations. One of the FAA's goals is to prevent inadvertent stalls, so 
allowing airplanes that are commonly used as rental airplanes to spin 
would defeat the goal. However, the FAA would consider accepting a 
dual-purpose airplane if the airplane manufacturer provided a system 
that could be changed mechanically or electronically from normal to 
aerobatic as a maintenance function rather than controlled by the 
pilot.
    The FAA proposes consolidating the performance requirements for 
high-speed multiengine airplanes and multiengine airplanes that weigh 
over 12,500 pounds. These airplanes are currently required to meet a 
series of one-engine-inoperative climb gradients. These climb gradients 
were based on part 25 requirements and intended for commuter category 
airplanes used in scheduled air service under parts 135 and 121. New 
airplanes certificated under part 23 are not eligible for operation in 
scheduled service under part 121, diminishing the utility of the 
commuter category for these airplanes.
    More recently, part 23 multiengine jets intended to be used under 
parts 91 or 135 have been certificated in the commuter category, using 
part 25 based climb gradient requirements. In the spirit of the 
proposed rule change, the FAA has decided that the one-engine-
inoperative climb requirements would be independent of the number of 
engines and some of the original requirements would be consolidated 
into a single requirement that would require performance very close to 
what is required today. This action intends to maintain the performance 
capabilities expected in 14 CFR part 135 operations.
    The FAA proposes changes in the flight characteristics rules to 
keep the safety intent of the existing requirements consistent with the 
other proposed part 23 sections. The current part 23 requirements are 
based on small airplanes, designed with reversible controls, which 
include some accommodations for stability augmentation and autopilots. 
The FAA believes the proposed language would capture the current 
requirements for flight characteristics and allows for varying degrees 
of automated flight control systems in the future.
    Finally, the FAA proposes adding a requirement to require 
certification levels 1 and 2 multiengine airplanes, not capable of 
climbing after a critical loss of thrust, to stall prior to reaching 
the minimum directional control speed (VMC).
b. Specific Discussion of Changes
i. Proposed Sec.  23.100, Weight and Center of Gravity
    Proposed Sec.  23.100 would require an applicant to determine 
weights and centers of gravity that provide limits for the safe 
operation of the airplane. Additionally, it would require an applicant 
to show compliance with each requirement of this subpart at each 
combination of weight and center of

[[Page 13467]]

gravity within the airplane's range of loading conditions using 
tolerances acceptable to the Administrator. Proposed Sec.  23.100 would 
also require the condition of the airplane at the time of determining 
its empty weight and center of gravity to be well defined and easily 
repeatable.
    Proposed Sec.  23.100 would capture the safety intent of current 
Sec. Sec.  23.21, Proof of compliance; 23.23, Load distribution limits; 
23.25, Weight limits; 23.29, Empty weight and corresponding center of 
gravity; and 23.31, Removable ballast. This proposed section would 
ensure an applicant considers the important weight and balance 
configurations that influence performance, stability, and control when 
showing compliance with the flight requirements. The main safety 
requirements of current Sec. Sec.  23.21-23.31 are located in current 
Sec. Sec.  23.21 and 23.23. Current Sec.  23.21 allows for a range of 
loading conditions shown by test or systematic investigation. The 
proposed rule would still allow for this flexibility, including the 
tolerances for flight test. Sections 23.25-23.31 provide definitions 
and directions for determining weights and centers of gravity and 
provides directions for informing the pilot. For these reasons, the 
information in these sections is more appropriate as a means of 
compliance.
ii. Proposed Sec.  23.105, Performance
    Proposed Sec.  23.105 would require an airplane to meet the 
performance requirements of this subpart in various conditions based on 
the airplane's certification and performance levels for which 
certification is requested. Proposed Sec.  23.105 also would require an 
applicant to develop the performance data required by this subpart for 
various conditions, while also accounting for losses due to atmospheric 
conditions, cooling needs, and other demands on power sources. Finally, 
proposed Sec.  23.105 would require the procedures used for determining 
takeoff and landing distances to be executed consistently by pilots of 
average skill in atmospheric conditions expected to be encountered in 
service.
    Proposed Sec.  23.105 would capture the safety intent of current 
Sec.  23.45, Performance--General. The safety intent of Sec.  23.45(a) 
is captured in proposed Sec.  23.105(a) and is essentially unchanged 
from the current rule, except to incorporate the proposed certification 
levels and speed divisions.
    Proposed Sec.  23.105(b) would capture the safety intent of Sec.  
23.45(b) by retaining Sec.  23.45(b)(1) requirements and combining 
Sec.  23.45(b)(2) and (b)(3) and allowing all airplanes to use the 
cooling climb limits as their upper temperature. The level of safety 
remains the same as the current part 23 because part 23 airplane pilots 
only have the limitations identified in the airplane flight manual, 
including engine temperature limits.
    Proposed Sec.  23.105(c) would also capture the safety intent of 
Sec.  23.45(f). The safety intent of the current rule is to ensure an 
average pilot can consistently get the same results as published in the 
Airplane Flight Manual (AFM). The FAA believes this requirement would 
ensure applicants either perform their performance tests in a 
conservative manner or add margins and procedures to the AFM 
performance section so an average pilot can achieve the same 
performance.
    Proposed Sec.  23.105(d) would require performance data to account 
for losses due to atmospheric conditions, cooling needs, and other 
demands. The current rule specifies the position of cowl flaps or other 
means for controlling the engine air supply. The proposed language 
accounts for airplane performance, if affected by the cooling needs of 
the propulsion system, which is the safety intent of Sec.  23.45, but 
would omit the details because they are more appropriate as a means of 
compliance.
    Proposed Sec.  23.105(d) would also capture the safety intent Sec.  
23.45(d) and (e). The safety intent of the current rule is to ensure 
the airplane performance accounts for minimum power available from the 
propulsion system, considering atmospheric and cooling conditions and 
accessories requiring power.
iii. Proposed Sec.  23.110, Stall Speed
    Proposed Sec.  23.110 would require an applicant to determine the 
airplane stall speed or the minimum steady flight speed for each flight 
configuration used in normal operations, accounting for the most 
adverse conditions for each flight configuration, with power set at 
idle or zero thrust.
    Proposed Sec.  23.110 would capture the safety intent of current 
Sec.  23.49, Stalling speed. Stall speeds are necessary to define 
operating and limiting speeds used to determine airplane performance. 
They also provide a basis for determining kinetic energy in emergency 
landing conditions. Therefore, determining stall speeds is required in 
the configurations used in the operation of the airplane.
    The FAA proposes removing the 61-knot stall speed division for 
single-engine airplanes from the rules because this speed has not been 
a limitation since 1992 with the addition of the options for stall 
speeds in excess of 61 knots in Sec.  23.562, Emergency landing dynamic 
conditions. Therefore, the 61-knot stall speed is a technical division 
rather than a limitation and would be more appropriate as a means of 
compliance.
    The FAA is changing its approach to crashworthiness. Instead of 
constraining the connection between stall speed and crashworthiness to 
a single fixed speed, the FAA proposes allowing alternative approaches 
to crashworthiness. The intent is to encourage incorporation of 
innovations from other industries to provide more occupant protection 
in the airframe. This approach would base occupant protection on the 
actual stall speed rather than a single mandated stall speed.
iv. Proposed Sec.  23.115, Takeoff Performance
    Proposed Sec.  23.115 would require an applicant to determine 
airplane takeoff performance, which includes the determination of 
ground roll and initial climb distance to 50 feet, accounting for stall 
speed safety margins, minimum control speeds; and climb gradients. 
Proposed Sec.  23.115 would also require the takeoff performance 
determination to include accelerate-stop, ground roll and initial climb 
to 50 feet, and net takeoff flight path, after a sudden critical loss 
of thrust for certification levels 1, 2, and 3 high-speed multiengine 
airplanes, multiengine airplanes with a maximum takeoff weight greater 
than 12,500 pounds, and certification level 4 multiengine airplanes.
    Proposed Sec.  23.115 would capture the safety intent of current 
Sec. Sec.  23.51, Takeoff speeds; and 23.61, Takeoff flight path. 
Takeoff distance information and the associated procedures for 
achieving those distances are necessary for the safe operation of all 
airplanes certified under part 23. Proposed Sec.  23.115 would require 
applicants to determine, develop, and publish distance and procedure 
data for the pilot to use. The effects of airplane weight, field 
temperature and elevation, winds, runway gradient, and runway surface 
also need to be available to the pilot because they affect airplane 
performance. For proposed simple entry-level airplanes, conservative 
analysis may supplement flight test while data for larger, higher 
performance airplanes are expected to provide the level of precision 
that is accepted today.
    Additionally, proposed Sec.  23.115 would require applicants to 
determine critical thrust loss cases for multiengine airplanes. Today, 
the loss of one engine on a two-engine airplane is the standard model. 
The future possibilities for the functions of engines, if different 
from

[[Page 13468]]

thrust, and how the engines are controlled, may determine critical 
thrust loss. For example, a large number of engines along the leading 
edge of a wing could function as a high-lift device as well as provide 
thrust.
    Historically, limited propulsion options and the need for inherent 
stability from reversible, mechanical control systems have restrained 
airplane configurations. The FAA anticipates that new propulsion 
systems and affordable electronic flight control systems will challenge 
these traditional designs and need alternative means of compliance. 
Speed multiples and factors used in current part 23 prescriptive 
requirements are based on traditional airplane configurations. Part 23 
mandates these details of design for compliance. The FAA believes 
removing these details would provide applicants with the agility and 
flexibility to address these new airplane configurations. The current 
factors will still apply for traditional configurations, but proposed 
performance-based requirements should allow rapid adoption of new means 
of compliance for future airplane configurations.
    The FAA proposes removing airplane categories and weight and 
propulsion certification divisions for multiengine jets over 6,000 
pounds and replacing them with divisions based on risk and performance. 
The commuter category, originally intended for the certification of 
airplanes over 12,500 pounds and up to 19 passengers, is currently used 
for larger business jets with less than ten passengers. The FAA 
proposes that high-speed, multiengine and multiengine airplanes over 
12,500 pounds should continue meeting the equivalent commuter category 
performance-based requirements. The historical assumption applied to 
jets was that they were fast, had high wing loadings, and used 
significant runway distances for takeoff and landing. Therefore, all 
jets were required to have guaranteed climb performance with one engine 
inoperative. This requirement does not currently apply to single engine 
jets. The proposed performance requirements would be based on number of 
passengers (certification level) and airplane performance (performance 
level), not weight or propulsion type. The proposed certification and 
performance levels approach would not offer a one-to-one relationship 
with the current requirements. A low-speed turbine-powered airplane may 
be more appropriately addressed by regulations currently applicable to 
piston-powered airplanes, while a piston-powered or a high-speed 
electric airplane may be more appropriately addressed by regulations 
currently used for the certification of turbine-powered airplanes. The 
proposed certification and performance level approach, while different 
from the current divisions, would capture the safety intent of part 23 
more appropriately than the current propulsion and weight divisions.
v. Proposed Sec.  23.120, Climb Requirements
    Proposed Sec.  23.120 would require an applicant to demonstrate 
various minimum climb performances out of ground effect, depending on 
the airplane's certification level, engines, and performance 
capability. This new provision would capture the safety intent of 
current Sec. Sec.  23.65, Climb: All engines operating; 23.67, Climb: 
One engine inoperative; and 23.77, Balked landing. Minimum climb 
performance information is necessary so pilots can determine if they 
have adequate clearance from obstacles beyond the end of the runway. 
New engine technologies, especially electric, would allow for 
alternative configurations that would invalidate many of the detailed 
test configuration and power assumptions that are in the current 
requirements.
    Part 23 currently has a large matrix for all the climb requirements 
that includes category, weight, and number of engines, resulting in 
over 20 different climb gradient requirements. This reflects the growth 
in the variety of different airplane types that has occurred since the 
certification regulations were first adopted in CAR 3. Because the FAA 
proposes simplifying these divisions using certification levels and 
airplane performance levels, it can eliminate required climb gradients 
for three and four engines. The FAA proposes basing multiengine climb 
gradients on critical loss for thrust and using the gradient for the 
current twin-engine airplanes because it has resulted in a safe service 
history. The FAA proposes replacing the term ``failure of the critical 
engine'' (which addresses a twin engine airplane) with ``critical loss 
of thrust'' for airplanes certificated under those provisions. The 
reason for replacing this term is that with configurations utilizing 
large numbers of engines, the failure modes may not follow the 
traditional failure modes as with the loss of one engine on a two-
engine airplane. Furthermore, the FAA proposes retaining and 
consolidating the climb gradients from current Sec.  23.67 because 
these gradients are important minimum performance requirements for 
maintaining the current level of safety.
    Proposed Sec.  23.120(a) would capture the safety intent of current 
Sec.  23.65. It would retain the existing climb gradients and 
atmospheric conditions required for pilot planning.
    Proposed Sec.  23.120(b) would capture the safety intent of current 
Sec.  23.67, and consolidates the weight and propulsion divisions into 
all engines operating, critical loss of thrust, and balked landing 
groups. Furthermore, for high-speed airplanes, after a critical loss of 
thrust, the FAA proposes reducing the number of required climb 
conditions for certification to one gradient at 400 feet (122 meters) 
above the takeoff surface. For the typical part 23 certified twin-
engine airplane, the required climb gradient at 400 feet (122 meters) 
above the takeoff surface is generally the most challenging. Airplanes 
that have the performance to meet this one requirement typically can 
meet all the current requirements. For certification levels 3 and 4, 
high-speed multiengine airplanes, the FAA proposes consolidating the 
configurations currently prescribed for the second segment climb and a 
discontinued approach. The climb gradient difference between these 
segments is 0.1 percent and uses the takeoff flap configuration rather 
than the approach flap configuration. Requiring only one climb gradient 
at 400 feet (122 meters) above the takeoff surface with the landing 
gear retracted and flaps in the approach position would maintain the 
current level of safety while reducing the requirements by eliminating 
initial, final, and discontinued approach climb tests. Because the 
proposed requirements would reduce the amount of climb testing for 
designs intended for use under part 91, applicants would also need to 
provide the traditional operational performance data, as is currently 
done, if the design is intended to be used for commercial operations 
under part 135 operating rules.
    The FAA also proposes to normalize the initial climb height to 50 
feet (15 meters) above the takeoff surface. The regulations for the 
certification of commuter category airplanes essentially adopted many 
of the part 25 climb requirements, including an initial climb height of 
35 feet (11 meters) above the takeoff surface. When the commuter 
category was adopted, the expectation was that these airplanes would be 
used in part 121 service. This expectation allowed the FAA to accept 
the part 25 assumption that takeoff distances would be factored; thus, 
providing a safety margin to offset the lower initial climb height. 
Part 23 requirements provide minimum safe operations for part 91, which 
does not require factored takeoff

[[Page 13469]]

distances. Therefore, allowing a 35 foot (11 meters) height above the 
takeoff surface is a lower safety margin than used for smaller 
airplanes and, for this reason, the FAA proposes to make all airplanes 
certificated under part 23 use 50 feet (15 meters) above the takeoff 
surface.
vi. Proposed Sec.  23.125, Climb Information
    Proposed Sec.  23.125 would require an applicant to determine the 
climb performance for--
     All single engine airplanes;
     Certification level 3 multiengine airplanes after a 
critical loss of thrust on takeoff in the initial climb configuration; 
and
     All multiengine airplanes during the enroute phase of 
flight with all engines operating and after a critical loss of thrust 
in the cruise configuration.
    Proposed Sec.  23.125 would also require an applicant to determine 
the glide performance of the airplane after a complete loss of thrust 
for single engine airplanes.
    Proposed Sec.  23.125 would capture the safety intent of current 
Sec. Sec.  23.63, Climb: General; 23.66, Takeoff climb: One-engine 
inoperative; 23.69, Enroute climb/descent; and 23.71, Glide: Single-
engine airplanes. The intent of these requirements is to provide pilots 
with climb and glide performance data that is important for safety, 
especially in conditions near the performance limits of the airplane. 
Sections 23.63, 23.66, and 23.69 are not minimum performance sections, 
but contain information used in the development of the AFM. Proposed 
Sec.  23.125 would require an applicant to determine climb performance. 
The performance data determination provides a good example of how the 
use of certification levels can allow simplified approaches to meet 
applicable airworthiness requirements for simple, and levels 1 and 2 
airplanes.
vii. Proposed Sec.  23.130, Landing
    Proposed Sec.  23.130 would require an applicant to determine the 
landing distance for standard temperatures at each weight and altitude 
within the operational limits for landing. The landing distance 
determination would start from a height of 50 feet (15 meters) above 
the landing surface, require the airplane to land and come to a stop 
(or for water operations, reach a speed of 3 knots) using approach and 
landing speeds, configurations, and procedures, which allow a pilot of 
average skill to meet the landing distance consistently and without 
causing damage or injury. Proposed Sec.  23.130 would require these 
determinations for standard temperatures at each weight and altitude 
within the operational limits for landing.
    Proposed Sec.  23.130 would capture the safety intent of current 
Sec.  23.73, Reference landing approach speed, and Sec.  23.75, Landing 
Distance. Landing distance information and the associated procedures 
for achieving those distances are necessary to prevent runway overruns. 
Applicants would be required to determine, develop, and publish 
distance and procedures data for use in pilot planning. Proposed Sec.  
23.130 would combine the current requirements to determine approach 
speed and landing distance because a determination of both is required 
for a landing distance determination.
viii. Proposed Sec.  23.200, Controllability
    Proposed Sec.  23.200 would require the airplane to be controllable 
and maneuverable, without requiring exceptional piloting skill, 
alertness, or strength, within the operating envelope, at all loading 
conditions for which certification is requested. This would would 
include during low-speed operations, including stalls, with any 
probable flight control or propulsion system failure, and during 
configuration changes. Proposed Sec.  23.200 would require the airplane 
to be able to complete a landing without causing damage or serious 
injury, in the landing configuration at a speed of VREF 
minus 5 knots using the approach gradient equal to the steepest used in 
the landing distance determination. Proposed Sec.  23.200 would require 
VMC not to exceed VS1 or VS0 for all 
practical weights and configurations within the operating envelope of 
the airplane for certification levels 1 and 2 multiengine airplanes 
that cannot climb after a critical loss of thrust. Proposed Sec.  
23.200 would also require an applicant to demonstrate those aerobatic 
maneuvers for which certification is requested and determine entry 
speeds.
    Proposed Sec.  23.200 would capture the safety intent of Sec. Sec.  
23.141, Flight Characteristics--General, 23.143, Controllability and 
Maneuverability--General; 23.145, Longitudinal control; 23.147 
Directional and lateral control; 23.149, Minimum control speed; 23.151, 
Acrobatic maneuvers; 23.153, Control during landing; 23.155, Elevator 
control force in maneuvers; 23.157, Rate of roll; 23.697(b) and (c), 
Wing flap controls. Proposed Sec.  23.200 would ensure the maneuvering 
flight characteristics of the airplane are safe and predictable 
throughout the flight envelope and result in repeatable, smooth 
transitions between turns, climbs, descents, and level flight. 
Configuration changes, such as flap extension and retraction, landing 
gear extension and retraction, and spoiler extension and retraction, 
along with probable failures resulting in asymmetric thrust, would also 
have to result in safe, controllable, and predictable characteristics.
    Proposed Sec.  23.200(a) and (b) would capture the safety intent of 
Sec. Sec.  23.143, Controllability and Maneuverability--General; 
23.145, Longitudinal control; 23.147, Directional and lateral control; 
23.149, Minimum control speed; 23.151, Acrobatic maneuvers; 23.153, 
Control during landings; 23.155, Elevator control force in maneuvers; 
and 23.157, Rate of roll. The FAA proposes limiting the requirements 
for practical loadings and operating altitudes without the use of 
exceptional piloting skill, alertness, or strength.
    Current part 23 provides prescriptive and detailed test 
requirements based on specific airplane configurations. Additionally, 
the current rules include flight test procedures that are based on 
traditional reversible controls and engine locations that are, in some 
cases, derived from airplanes designed in the 1930's. The FAA proposes 
performance-based requirements that would remain applicable to 
traditionally designed airplanes, but allow alternative approaches to 
showing compliance based on new configurations, flight control systems, 
engine locations, and number of engines.
    Proposed Sec.  23.200(c) would require all certification levels 1 
and 2 multiengine airplanes that lack the performance to climb after a 
critical loss of thrust to stall before loss of directional control. 
This is a new requirement and it targets the high number of fatal 
accidents that occur after an engine failure in this class of airplane. 
Light multiengine airplanes that lack the performance to climb after 
the critical loss of thrust are especially susceptible to this type of 
accident. The Part 23 Reorganization ARC discussed and several members 
proposed that all multiengine airplanes have guaranteed climb 
performance after a critical loss of thrust. Ultimately, this approach 
was rejected, as it could impose a significant cost on the production 
of training airplanes. Furthermore, several members pointed out that 
the safety concern was not that the airplane could not climb on one 
engine, but rather that the airplane would depart controlled flight at 
low speeds above stall as a result of asymmetric thrust. The FAA agrees 
that loss of control caused by asymmetric thrust is the critical safety 
issue that should be addressed and the FAA believes that the proposed 
rule responds to this concern.

[[Page 13470]]

    The FAA recognizes concerns regarding the proposed requirement--if 
the airplane is allowed to stall, the asymmetric thrust will still 
cause the airplane to lose directional control and likely depart 
controlled flight. The FAA agrees, but believes that pilots are 
typically more aware of their stall speeds than minimum control speed, 
especially during turns. Furthermore, these airplanes would be required 
to meet the proposed stall warning and stall characteristic 
requirements, which the FAA expects would provide additional safety 
margins beyond current requirements. Finally, the system that provides 
stall warning could also be designed to provide VMC warning.
ix. Proposed Sec.  23.205, Trim
    Proposed Sec.  23.205 would require the airplane to maintain 
longitudinal, lateral, and directional trim under various conditions, 
depending on the airplane's certification level, without allowing 
residual forces to fatigue or distract the pilot during likely 
emergency operations, including a critical loss of thrust on 
multiengine airplanes.
    Proposed Sec.  23.205 would capture the safety intent of current 
Sec.  23.161, Trim. Section 23.161(a) addresses the safety intent while 
paragraphs (b), (c), (d), and (e) provide prescriptive details on how 
to do flight testing for traditionally configured airplanes and are 
more appropriate for inclusion in means of compliance.
x. Proposed Sec.  23.210, Stability
    Proposed Sec.  23.210 would require airplanes not certified for 
aerobatics to have static and dynamic longitudinal, lateral, and 
directional stability in normal operations, and provide stable control 
force feedback throughout the operating envelope. Proposed Sec.  23.210 
would also preclude any airplane from exhibiting any divergent 
stability characteristic so unstable as to increase the pilot's 
workload or otherwise endanger the airplane and its occupants.
    Proposed Sec.  23.210 would capture the safety intent of the 
current Sec. Sec.  23.171, Stability--General; 23.173, Static 
longitudinal stability; 23.175, demonstration of static longitudinal 
stability; 23.177, Static directional and lateral stability; 23.179, 
Instrumented stick force measurements; and 23.181, Dynamic stability. 
The current requirements have their origins in Aeronautics Bulletin 7, 
amendment 7a, effective October 1, 1934, which predates CAR 3. These 
airplane handling quality and stability requirements were based on the 
technology associated with simple mechanical control systems and what 
was considered acceptable on existing airplanes of the time. Although 
many of these requirements are still appropriate for traditional flight 
control systems, they do not take into account the capabilities of new 
computer-based flight control systems. The FAA recognizes the 
availability of hybrid reversible and automated flight control systems 
and proposes performance-based language that would allow their 
installation in part 23 certificated airplanes without the use of 
special conditions, while still maintaining adequate requirements for 
reversible controls. The intent is to facilitate the use of systems 
that may enhance safety while reducing pilot workload.
xi. Proposed Sec.  23.215, Stall Characteristics, Stall Warning, and 
Spins
    Proposed Sec.  23.215 would require an airplane to have 
controllable stall characteristics in straight flight, turning flight, 
and accelerated turning flight with a clear and distinctive stall 
warning that would provide sufficient margin to prevent inadvertent 
stalling. Proposed Sec.  23.215 would allow for alternative approaches 
to meeting this requirement for certification levels 1 and 2 airplanes 
and certification level 3 single-engine airplanes, not certified for 
aerobatics, in order to avoid a tendency to inadvertently depart 
controlled flight. Proposed Sec.  23.215 would require airplanes 
certified for aerobatics to have controllable stall characteristics and 
the ability to recover within one and one-half additional turns after 
initiation of the first control action from any point in a spin. 
Additionally, the airplane would not be allowed to exceed six turns or 
any greater number of turns for which certification is requested while 
remaining within the operating limitations of the airplane. Proposed 
Sec.  23.215 would preclude airplanes certified for aerobatics from 
having spin characteristics that would result in unrecoverable spins 
due to pilot disorientation or incapacitation or any use of the flight 
or engine power controls.
    Proposed Sec.  23.215 would capture the safety intent of current 
Sec. Sec.  23.201, Wings level stall; 23.203, Turning flight and 
accelerated turning stalls; 23.207, Stall warning; and 23.221, 
Spinning. Historically, the FAA focused its requirements on the ability 
of the airplane to recover from a one-turn or three-second spin more 
than on the stall characteristics of the airplane. From the first fatal 
stall accident in the Wright Flyer airplane to today's fatal stall 
accidents, the number one cause in small airplanes is a departure from 
controlled flight following an inadvertent stall.
    Except for accidental departures from controlled flight during 
stall training, most of these inadvertent departures occur in close 
proximity to the ground, and because of this, the current requirement 
to recover from a one-turn or three-second spin may not be the best 
method to assess the safety of the airplane. Even an experienced pilot 
may not have enough altitude to recover from the spin before impacting 
the ground. For this reason, the FAA proposes to delete the one-turn/
three-second spin recovery requirement for normal category airplanes. 
Instead, the FAA proposes to increase the stall characteristics 
requirements by requiring that all certification levels 1 and 2 
airplanes and certification level 3 single-engine airplanes provide 
substantial departure resistance to prevent inadvertent stalls from 
resulting in a departure from controlled flight and becoming fatal 
accidents.
    Accident studies show that even hitting the ground as a result of a 
stall can be survivable if the airplane is still in controlled flight. 
Conversely, impacting the ground out of control is typically fatal. The 
FAA envisions numerous alternative approaches to meeting the proposed 
requirements, ranging from one extreme of spin resistance to the other 
extreme of a total systems-based approach such as stick pusher. 
Furthermore, there are envelope protection systems and stall warning 
concepts that could also be considered when assessing departure 
resistance. The possible approaches to meeting the proposed 
requirements are so broad that these alternatives would be better 
addressed in means of compliance. This level of protection may vary 
based on the characteristics of the airplane, but the FAA expects this 
change in design philosophy would increase the level of protection 
designed into airplanes under this proposed rule. Certification level 3 
multiengine airplanes and certification level 4 airplanes historically 
have not had a large number of departure-related accidents. While the 
FAA encourages manufacturers to consider designing departure resistance 
into these airplanes, the FAA does not propose adding a new requirement 
for certification level 3 multiengine airplanes and certification level 
4 airplanes.
    The FAA also proposes revising stall warning requirements by 
removing prescriptive speed based stall warning requirements and 
requiring a clear and distinctive warning with sufficient

[[Page 13471]]

warning margin for the pilot to prevent a stall. Historically, stall 
warning systems in part 23 airplanes have been simple, mechanical vanes 
that may or may not provide reasonable lead-time to prevent a stall. 
These systems also can provide false alerts when they are not needed, 
creating a nuisance. Furthermore, similar sounding warning horns that 
alert the pilot of other situations can result in the pilot either 
becoming used to the warning sounds or mistaking the stall warning for 
another warning such as the autopilot disconnect horn. The FAA believes 
removing the current prescriptive speed based stall warning from the 
rules would encourage the installation of better, more effective low 
speed awareness systems that may use angle of attack, a speed decay 
rate, or clear voice commands to alert the pilot.
xii. Proposed Sec.  23.220, Ground and Water Handling Characteristics
    Proposed Sec.  23.220 would require airplanes intended for 
operation on land or water to have controllable longitudinal, and 
directional handling characteristics during taxi, takeoff, and landing 
operations. Proposed Sec.  23.220 would also require an applicant to 
establish a maximum wave height shown to provide for controllable 
longitudinal, and directional handling characteristics and any 
necessary water handling procedures for those airplanes intended for 
operation on water.
    Proposed Sec.  23.220 would capture the safety intent of Sec. Sec.  
23.231, Longitudinal stability and control; 23.233, Directional 
stability and control; 23.235, Operation on unpaved surfaces; 23.237, 
Operation on water; and 23.239, Spray characteristics.
xiii. Proposed Sec.  23.225, Vibration, Buffeting, and High-Speed 
Characteristics
    Proposed Sec.  23.225 would preclude vibration and buffeting from 
interfering with the control of the airplane or causing fatigue to the 
flightcrew, for operations up to VD/MD. Proposed 
Sec.  23.225 would allow stall warning buffet within these limits. 
Proposed Sec.  23.225 would preclude perceptible buffeting in cruise 
configuration at 1g and at any speed up to VMO/
MMO, except stall buffeting for high-speed airplanes and all 
airplanes with a maximum operating altitude greater than 25,000 feet 
(7,620 meters) pressure altitude. Proposed Sec.  23.225 would require 
an applicant seeking certification of a high-speed airplane to 
determine the positive maneuvering load factors at which the onset of 
perceptible buffet occurs in the cruise configuration within the 
operational envelope and preclude likely inadvertent excursions beyond 
this boundary from resulting in structural damage. Proposed Sec.  
23.225 would also require high-speed airplanes to have recovery 
characteristics that do not result in structural damage or loss of 
control, beginning at any likely speed up to VMO/
MMO, following an inadvertent speed increase and a high-
speed trim upset.
    Proposed Sec.  23.225 would capture the safety intent of current 
Sec. Sec.  23.251, Vibration and buffeting; 23.253, High speed 
characteristics; and 23.255, Out of trim characteristics. Proposed 
Sec.  23.225(a), (b), and (c) would capture the safety of current Sec.  
23.251(a), (b), and (c). The current safety intent of Sec. Sec.  23.253 
and 23.255 are incorporated in proposed Sec.  23.225(d).
    Proposed Sec.  23.225(d)(1) addresses the current language in Sec.  
23.253, which indirectly divides the airplanes by engine type rather 
than performance. These requirements have typically been applied 
automatically to turbine-powered airplanes with the assumption that all 
turbine-powered airplanes flew fast and high. Piston or electric 
airplanes were not required to meet these requirements even if they 
were faster than many turboprops, because of propulsion assumptions in 
the past. For this reason, the FAA is amending this requirement to be 
based on performance instead of propulsion type using the same high-
speed criteria from other subpart B sections. The existing details 
would be removed from the rules, as they are more appropriate as means 
of compliance because it would allow for alternatives for non-
traditional airplanes, such as very fast piston airplanes.
    Proposed Sec.  23.225(d)(2) would address the current safety intent 
in Sec.  23.255 by relying on performance and design characteristics 
without discriminating based on propulsion type. The specific design 
details are more appropriate as means of compliance.
xiv. Proposed Sec.  23.230, Performance and Flight Characteristics 
Requirements for Flight in Icing Conditions
    Proposed Sec.  23.230 would require an applicant requesting 
certification for flight in icing conditions to demonstrate compliance 
with each requirement of this subpart. Exceptions to this rule would be 
those applicable to spins and any requirement that would have to be 
demonstrated at speeds in excess of 250 KCAS, VMO or 
MMO, or a speed that an applicant demonstrates the airframe 
would be free of ice accretion. Proposed Sec.  23.230 would require the 
stall warning for flight in icing conditions and non-icing conditions 
to be the same. Proposed Sec.  23.230 would require an applicant 
requesting certification for flight in icing conditions to provide a 
means to detect any icing conditions for which certification is not 
requested and demonstrate the airplane's ability to avoid or exit those 
conditions. Proposed Sec.  23.230 would also require an applicant to 
develop an operating limitation to prohibit intentional flight, 
including takeoff and landing, into icing conditions for which the 
airplane is not certified to operate. Proposed Sec.  23.230 would also 
increase safety by adding optional icing conditions a manufacturer may 
demonstrate its airplane can either safely operate in, detect and 
safely exit, or avoid. Proposed Sec.  23.230 would only apply to 
applicants seeking certification for flight in icing.
    Proposed Sec.  23.230 would capture the safety intent of the 
performance and flight characteristics requirements in current Sec.  
23.1419(a) and along with proposed Sec. Sec.  23.940, Powerplant ice 
protection, and 23.1405, Flight in icing conditions, and their 
respective means of compliance would address NTSB safety 
recommendations A-96-54 and A-96-56. Section 23.1419 specifies that 
airplanes must be able to operate safely in the icing conditions 
identified in appendix C to part 25, which encompass cloud size drops 
of less than 100 microns in diameter. Freezing drizzle (i.e., drops up 
to 500 microns in diameter) and freezing rain (i.e., drops greater than 
500 microns in diameter) icing conditions, which can result in ice 
accretion aft of leading edge ice protection systems, are not included 
in appendix C to part 25. Amendment 25-140 (79 FR 65507, November 4, 
2014) added these icing conditions to appendix O to part 25 and are not 
being defined in proposed Sec.  23.230. The FAA believes that the 
definitions of these optional icing conditions would be more 
appropriate as a means of compliance. The standards for ``capable of 
operating safely'' in these conditions would be the same as cloud icing 
with additional icing conditions in the takeoff phase.
    If certification for flight in the optional freezing drizzle or 
freezing rain conditions is not sought, proposed Sec.  23.230 would 
require these conditions be avoided or detected and exited safely. The 
means of compliance for the latter, detect and exit the situation, 
would be similar to current guidance in AC 23.1419-2D, Certification of 
Part 23 Airplanes for Flight in Icing Conditions, and is currently 
applied during part 23

[[Page 13472]]

airplane icing certifications. These criteria are not as extensive as 
recommended by the Part 23 Icing ARC, but the FAA did not want to 
impose an additional burden on industry because the service history of 
airplanes certified under part 23 and the latest icing regulations at 
amendment 23-43 (58 FR 18958, April 9, 1993) show no SLD related 
accidents. The FAA believes the safety of the existing fleet can be 
greatly increased by improving the freezing drizzle and freezing rain 
capability of automated surface weather observation systems and pilot 
education and training of the limits of icing certification.
    Proposed Sec.  23.230(b) would provide an option to avoid, in lieu 
of detecting and exiting, the freezing drizzle or freezing rain icing 
conditions for which the airplane is not certified. This option is not 
in current guidance and such technology currently does not exist. The 
rule would provide an option in the event the technology is developed. 
The FAA believes avoiding rather than detecting and exiting would 
provide for safer airplane operations and reduce certification costs.
    Proposed Sec.  23.230(c) would require an AFM limitation to 
prohibit flight in icing conditions for which the airplane is not 
certified. This reflects current guidance in AC 23.1419-2D, which most 
manufacturers of new part 23 icing certified airplanes follow today. A 
minority of new manufacturers are not using AC 23.1419-2D guidance and 
have inserted AFM limitation language that reflects Airworthiness 
Directives (AD) that were issued globally to pneumatic boot-equipped 
airplanes between 1996 and 1998. The ADs in the below table require 
immediate exit from severe icing and warn that freezing drizzle and 
freezing rain may be conducive to severe icing. The proposed new 
limitation is intended to prohibit flight in known icing conditions, 
not forecast conditions.

------------------------------------------------------------------------
             Airplane model                   Docket        Final rule
------------------------------------------------------------------------
Aerostar Aircraft Corporation Models PA-     97-CE-56-AD        98-04-23
 60-600, PA-60-601, PA-60-601P, PA-60-
 602P, and PA-60-700P Airplanes.........
Pilatus Britten-Norman Ltd., Models BN-      97-CE-54-AD        98-04-21
 2A, BN-2B, and BN-2T Airplanes.........
Pilatus Aircraft Ltd., Models PC-12 and      97-CE-53-AD        98-20-28
 PC-12/45 Airplanes.....................
Partenavia Costruzioni Aeronauticas,         97-CE-51-AD        98-04-20
 S.p.A. Model P68, AP68TP 300, AP68TP
 600 Airplanes..........................
Mitsubishi Heavy Industries, Ltd., MU-2B     96-CE-61-AD        96-25-02
 Series Airplanes.......................
Harbin Aircraft Manufacturing Corp.,         97-CE-50-AD        98-04-19
 Model Y12 IV airplanes.................
Empresa Brasileira de Aeronautica S.A.       96-CE-02-AD        96-09-12
 Airplanes. (Embraer) Models EMB-110P1
 and EMB-110P2 Airplanes................
Dornier Luftfahrt GmbH, 228 Series           96-CE-04-AD        96-09-14
 Airplanes..............................
De Havilland, Inc., DHC-6 Series             96-CE-01-AD        96-09-11
 Airplanes..............................
The Cessna Aircraft Company, 208 Series.     96-CE-05-AD        96-09-15
The Cessna Aircraft Company, Model T210R     98-CE-19-AD        98-20-33
 airplane...............................
The Cessna Aircraft Company, Models          97-CE-62-AD     98-05-14 R1
 T210, P210, P210R airplanes............
The Cessna Aircraft Company Models T303,     97-CE-63-AD        98-04-28
 310R, T310R, 335, 340A, 402B, 402C,
 404, F406, 414, 414A, 421B, 421C, 425,
 and 441 Airplanes......................
Jetstream Aircraft Limited Models 3101       96-CE-07-AD        96-09-17
 and 3201 Airplanes.....................
The New Piper Aircraft PA-23, PA-30, PA-     98-CE-77-AD        99-14-01
 31, PA-34, PA-39, PA-40, and PA-42
 Series Airplanes.......................
The New Piper Aircraft Corporation           97-CE-60-AD        98-04-26
 Models PA-46-310P and PA-46-350P
 Airplanes..............................
Beech Aircraft Corporation Models 99,        96-CE-03-AD        96-09-13
 99A, A99A, B99, C99, B200, B200C, 1900,
 1900C, and 1900D Airplanes.............
Raytheon Aircraft Company 200 Series         98-CE-17-AD        98-20-38
 Airplanes..............................
Raytheon Aircraft Company Models E55,        97-CE-58-AD        98-04-24
 E55A, 58, 58A, 58P, 58PA, 58TC, 58TCA
 Airplanes, and 60, 65-B80, 65-B90, 90,
 F90, 100, 300, and B300 Series
 Airplanes..............................
Raytheon Aircraft Company Model 2000         97-CE-59-AD        98-04-25
 Airplanes..............................
AeroSpace Technologies Of Australia Pty      97-CE-49-AD        98-04-18
 Ltd., Models N22B and N24A.............
SIAI Marchetti, S.r.1 Models SF600 and       97-CE-64-AD        98-05-15
 SF600A Airplanes.......................
SOCATA--Groupe AEROSPATIALE, Model TBM       97-CE-55-AD        98-04-22
 700 Airplanes..........................
Twin Commander Aircraft Corporation          97-CE-57-AD        98-20-34
 Models 500, 500-A, 500-B, 500-S, 500-U,
 520, 560, 560-A, 560-E, 560-F, 680, 680-
 E, 680FL(P), 680T, 680V, 680W, 681,
 685, 690, 690A, 690B, 690C, 690D, 695,
 695A, 695B, and 720 Airplanes..........
Fairchild Aircraft Corporation, SA226        96-CE-06-AD        96-09-16
 and SA227 Series Airplanes.............
------------------------------------------------------------------------

    Recently, manufacturers of airplanes certificated under part 23 
have proposed inhibiting, or optimizing, bleed air ice protection 
systems above an altitude of 30,000 feet (9,144 meters) because the 
icing conditions defined in the appendix C to part 25 are limited to 
below this altitude. The FAA believes ice protection design at high 
altitude should be addressed as a means of compliance and not in the 
proposed rule due to various acceptable design solutions. An industry 
means of compliance would negate the need for a special condition or 
means of compliance issue paper currently required for these projects.
xv. Current Subpart B Regulations Relocated to Other Proposed Subparts
    The FAA proposes addressing the safety intent of Sec.  23.33, 
Propeller speed and pitch limits, in Sec.  23.900(a) of the propulsion 
rules. Additionally, the first part of the current Sec.  23.251(a) that 
addresses structural damage has been relocated and is now addressed 
under ``flutter'' in proposed subpart C to part 23.
    The FAA proposes adopting the Part 23 Icing and Part 23 
Reorganization ARC's recommendations to move performance and flight 
characteristics requirements in icing, currently in Sec.  23.1419, to 
subpart B, so that proposed Sec.  23.1405 only contains systems 
requirements. Proposed Sec.  23.230(a) would also include stall warning 
requirements. Current guidance contains these stall warning 
recommendations (i.e., margin and type of stall) and service history 
shows them to be necessary for safe flight in icing conditions. The 
exceptions for spin and high-speed requirements are consistent with the 
current rule and industry practice that have shown to provide an 
adequate level of safety in icing conditions. The FAA determined that 
the evaluations of ice contaminated tailplane stall susceptibility, 
lateral control in icing, and autopilot operation in icing, which are 
included in current guidance for part 23 icing certification,

[[Page 13473]]

are more appropriately addressed as a means of compliance.
xvi. Removal of Subpart B Current Regulations
    The FAA proposes removing Sec.  23.45(g) that requires takeoff and 
landing distances be determined on a smooth, dry, hard-surfaced runway. 
The FAA believes that most performance tests would be done on smooth, 
dry, hard-surfaced runways because these surfaces provide applicants 
with the best results. Performance determinations on surfaces other 
than smooth, dry hard surfaces would provide conservative results and 
be acceptable as long as the surface was specified in the AFM. 
Therefore, the FAA believes retaining this requirement is unnecessary.
    The FAA proposes removing Sec.  23.63, Climb: General, which 
addresses the general climb requirements, because the safety intent 
contained in this section is redundant with the safety intent proposed 
in Sec.  23.125 and the testing procedures contained in Sec.  23.63 are 
more appropriate for inclusion in means of compliance.
    The FAA proposes removing current Sec.  23.221(a) and (b), which 
address spinning requirements for normal and utility category 
airplanes, and would no longer be necessary. The increased focus on 
preventing stall-based departures along with improved stall margin 
awareness would provide a level of safety higher than would be achieved 
through spin testing.
    The FAA proposes removing the reference to appendix C to part 25, 
part II, currently in Sec.  23.1419, Ice protection, paragraph (a), 
when relocating Sec.  23.1419 to proposed Sec.  23.230 and 23.1405. 
Part II is a means of compliance for determining critical ice 
accretions on transport category airplanes and is not applicable to 
airplanes certified under part 23.
3. Subpart C--Structures
a. General Discussion
    The FAA's intent in proposed subpart C is to provide a regulatory 
framework that maintains the current level of safety while (1) allowing 
for certification of unique airplane configurations with new technology 
and materials, and (2) supporting new means of compliance, testing, and 
analysis. To support new technologies, the FAA proposes to incorporate 
the safety intent of recent special conditions for airplanes equipped 
with systems that affect structural performance, such as load 
alleviation systems, in proposed Sec.  23.305. To support new means of 
compliance, the FAA proposes in Sec.  23.600 to emphasize a holistic 
approach to occupant safety, which would allow certain applicants to 
omit current required dynamic seat testing.
    It is not the FAA's intent to reduce the level of safety in the 
proposed subpart C. The FAA based the prescriptive requirements in 
current subparts C and D on service history, historic test data, and 
lessons learned. These requirements have provided a level of safety 
where structural failure is rare and most often attributable to 
airplane upset or pilot disorientation in instrument meteorological 
conditions. A means of compliance to proposed subpart C must maintain 
the level of safety provided by the current regulations. Applicants 
would need to substantiate the level of safety for proposed means of 
compliance that deviate from the prescriptive regulations.
    Proposed subpart C would replace current subpart C and include 
those sections of current subpart D that are applicable to the 
airframe. We have arranged proposed subpart C into the following five 
topics:

     General: Including Sec.  23.300, Structural design 
envelope; and Sec.  23.305 Interaction of systems and structures.
     Structural Loads: Including Sec.  23.310, Structural 
design loads; Sec.  23.315, Flight load conditions; Sec.  23.320, 
Ground and water load conditions; Sec.  23.325, Component loading 
conditions; and Sec.  23.330, Limit and ultimate loads.
     Structural performance: Including Sec.  23.400, 
Structural strength; Sec.  23.405, Structural durability; and Sec.  
23.410, Aeroelasticity.
     Design: Including Sec.  23.500, Structural design; 
Sec.  23.505, Protection of structure; Sec.  23.510, Materials and 
processes; and Sec.  23.515, Special factors of safety.
     Structural occupant protection: Included in Sec.  
23.600, Emergency conditions.

    The FAA proposes removing the content of current appendix A to part 
23, Simplified design load criteria; appendix C to part 23, Basic 
landing conditions; appendix D to part 23, Wheel spin-up and spring-
back loads; and appendix I to part 23, Seaplane loads. The content of 
these current part 23 appendices is more appropriate for inclusion in 
means of compliance. The FAA also proposes removing appendix B to part 
23, Reserved, since the content of this appendix was removed at 
amendment 23-42 (56 FR 344, January 3, 1991). Refer to appendix 1 of 
this preamble for a cross-reference table detailing how the current 
regulations are addressed in the proposed part 23 regulations.
b. Specific Discussion of Changes
i. Proposed Sec.  23.300, Structural Design Envelope
    Proposed Sec.  23.300 would require an applicant to determine the 
structural design envelope, which describes the range and limits of 
airplane design and operational parameters for which an applicant would 
show compliance with the requirements of this subpart. Proposed Sec.  
23.300 would capture the safety intent of current Sec. Sec.  23.321, 
Loads--General, paragraphs (b) and (c); 23.333, Flight envelope, 
paragraphs (a), (b), and (d); 23.335, Design airspeeds; 23.337, Limit 
maneuvering load factors, paragraphs (a) and (b); and 23.343, Design 
fuel loads, paragraphs (a) and (b).
    Proposed Sec.  23.300 would require the applicant to determine and 
document the range of airplane and operational parameters for which the 
applicant will show compliance with the requirements of subpart C. 
These parameters would include the design airspeeds and maneuver load 
factors often depicted as a V-n diagram. An applicant would be required 
to determine design airspeeds, including the design maneuvering speed 
(VA), the design cruising speed (VC), the design 
dive speed (VD), design flap and landing gear speeds, and 
any other speed used as a design limitation. For certification of level 
4 airplanes, an applicant would be required to determine a rough air 
penetration speed, VB.
    Additionally, applicants would have to determine the design 
maneuver load factors based on the intended usage of the airplane and 
the values associated with the level of safety experienced with current 
designs. Applicants have rarely used the relief for maneuvering load 
factors based on airplane capabilities in current Sec.  23.337(c). The 
FAA views this relief as an application of physical principles, and 
believes that this current requirement does not need to be addressed in 
proposed Sec.  23.300.
    Design weights and inertia parameters are also part of the 
structural design envelope. Design weights include the empty weight, 
maximum weight, takeoff and landing weight, and maximum zero fuel 
weight. The range of center of gravity locations at these and other 
weights is depicted as the weight center of gravity envelope. An 
applicant would have to determine the weight and center of gravity of 
occupants, payload, and fuel as well as any mass moments of inertia 
required for loads or flutter analysis. An applicant would also have to 
specify any other parameters that describe the structural design 
envelope. These parameters include maximum

[[Page 13474]]

altitude limitations, Mach number limitations, and control surface 
deflections.
ii. Proposed Sec.  23.305, Interaction of Systems and Structures
    Proposed Sec.  23.305 would provide a regulatory framework for the 
evaluation of systems intended to modify an airplane's structural 
design envelope or structural performance and other systems whose 
normal operating state or failed states may affect structural 
performance. Compliance with proposed Sec.  23.305 would provide 
acceptable mitigation of structural hazards identified in the 
functional hazard assessments required by proposed Sec.  23.1315.
    Proposed Sec.  23.305 would apply to airplanes equipped with--
     Structural systems, including load alleviation systems, 
where the intended function is to modify structural performance, to 
alleviate the impact of subpart C requirements, or provide a means of 
compliance to subpart C requirements; and
     Systems where the intended function is non-structural, but 
whose normal operation or failure states affect the structural design 
envelope or structural performance, and would include fuel management 
systems, flight-envelope protection systems, and active control 
systems.
    Under the current regulations, an applicant seeking certification 
of airplanes incorporating structural and non-structural systems must 
ensure that failures of these systems will not result in exceeding the 
structural design envelope or the structural design loads, or other 
structural performance characteristics. An applicant has the option of 
designing the structure to the full subpart C and subpart D 
requirements, including margins of safety, with the system in its 
failed state. This option may result in increased structural weight and 
reduced airplane performance and utility.
    Proposed Sec.  23.1315 in subpart F would apply to both structural 
and non-structural systems. Guidance material for current Sec.  
23.1309, the corresponding regulation to proposed Sec.  23.1315, allows 
for different acceptable values for likelihood of failures based on the 
severity of the hazard, airplane weight, and method of propulsion. 
These different values encourage the incorporation of equipment that 
improves pilot situational awareness and other systems that promote the 
overall airplane level of safety.
    In most cases, means of compliance with proposed Sec.  23.305 would 
follow an approach somewhat similar to that used in the guidance 
material for current Sec.  23.1309. Structural failures resulting in 
fatalities are rare, occurring at a rate of approximately 3 x 
10-8 per flight hour for small airplanes. The reason for 
incorporating structural systems is not, in general, to improve safety, 
but rather to reduce structural weight and thereby improve airplane 
performance. Proposed Sec.  23.305 would require that the level of 
safety must be the same for airplanes equipped with systems that affect 
the structure and airplanes without such systems.
    An existing acceptable means of complying with proposed Sec.  
23.305 is provided in several existing special conditions that address 
the interaction of systems and structures, for example, FAA Special 
Condition 25-390-SC.\20\ Most of these special conditions address load 
alleviation systems. Load alleviation systems counteract the effects of 
gust and maneuver loads and allow an applicant to design a lighter 
structure, thereby improving the performance and utility of the 
airplane. These special conditions require that an applicant design the 
structure to the required structural safety margins with the load 
alleviation system its normal functioning state. The special conditions 
provide a means for an applicant to maintain the required structural 
safety margins with the system in its failed state by adjusting the 
required safety margins based on the likelihood of system failure. 
Systems that fail frequently require higher safety margins than systems 
that rarely fail in order to maintain the same level of safety. The 
means of compliance described in these special conditions allow an 
applicant to utilize the benefits of structural systems and potentially 
eliminate weight and performance penalties associated with structural 
hazards due to system failures.
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    Applicants who use the means of compliance described in the 
existing special conditions would be able to use data developed for 
compliance with proposed Sec.  23.1315. This data includes 
identification of failure modes, identification of hazards resulting 
from the failure modes, and the likelihood of the occurrence of the 
failure modes. With or without the proposed Sec.  23.305 requirements, 
an applicant would have to account for structural performance with the 
system in its normal operating and failed states and evaluate the 
system for compliance to the proposed Sec.  23.1315. The FAA does not 
expect that additional detailed structural analysis would be required 
for compliance with proposed Sec.  23.305 other then the application of 
optional lower safety margins to the structural performance analysis.
    Proposed Sec.  23.305 would allow an applicant to realize the value 
of structural and non-structural systems and would potentially allow 
reduced structural weight of the airplane. The magnitude of the weight 
reduction would depend on the functional characteristics of the systems 
and the likelihood of system failures. The FAA believes proposed Sec.  
23.305 would reduce the need for special conditions that deal with 
interaction of systems and structures, saving time and effort for the 
FAA and the applicant.
iii. Proposed Sec.  23.310, Structural Design Loads
    Proposed Sec.  23.310 would require an applicant to determine 
structural design loads resulting from any externally or internally 
applied pressure, force, or moment, which may occur in flight, ground 
and water operations, ground and water handling, and while the airplane 
is parked or moored. Proposed Sec.  23.310 would require the applicant 
to determine structural design loads at all combinations of parameters 
on and within the boundaries of the structural design envelope which 
result in the most severe loading conditions. Proposed Sec.  23.310 
would also require the magnitude and distribution of these loads to be 
based on physical principles and would be no less than service history 
has shown can occur within the structural design envelope.
    Proposed Sec.  23.310 would capture the safety intent of Sec. Sec.  
23.301, Loads; 23.302, Canard or tandem wing configurations; 23.321, 
Flight Loads--General, paragraph (a); and 23.331, Symmetrical flight 
conditions. Proposed Sec.  23.310 would also capture the intent of 
several current requirements for sound and physics-based engineering 
evaluations. An example is in current Sec.  23.301(b), which requires 
that the forces and moments applied to the airplane must balance in 
equilibrium, and the distribution of loads on the airplane must 
reasonably approximate actual conditions. The part 23 regulations 
should not need to prescribe basic physical principles, sound 
engineering judgment, and common sense. Proposed Sec.  23.310 would 
place the burden on the applicant to properly account for loads acting 
on the structure.

[[Page 13475]]

iv. Proposed Sec.  23.315, Flight Load Conditions
    Proposed Sec.  23.315 would require an applicant to determine the 
loads resulting from vertical and horizontal atmospheric gusts, 
symmetric and asymmetric maneuvers, and, for multiengine airplanes, 
failure of the powerplant unit which results in the most severe 
structural loads. Proposed Sec.  23.315 would capture the safety intent 
of current Sec. Sec.  23.333, Flight envelope, paragraph (c); 23.341, 
Gust loads factors; 23.347, Unsymmetrical flight conditions; 23.349, 
Rolling conditions; 23.351, Yawing conditions; 23.367, Unsymmetrical 
loads due to engine failure; 23.421, Balancing loads; 23.423, 
Maneuvering loads; 23.425, Gust loads; 23.427, Unsymmetrical loads; 
23.441, Maneuvering loads; 23.443, Gust loads; and 23.445, Outboard 
fins or winglets, paragraphs (b), (c), and (d).
    These current part 23 sections establish prescriptive requirements 
for gust loads and symmetrical, rolling, and yawing maneuvering loads, 
acting on the wing, horizontal tail, vertical tail, and other lifting 
surfaces. Portions of the current sections, such as Sec.  23.331(c), 
are restatements of basic physical principles. Proposed Sec.  23.315 
would remove this language.
    The FAA's intent is not to lessen the structural load requirements. 
The current prescriptive flight load requirements have established a 
level of safety where structural failure due to overloading is rare. 
When structural failures do occur, the most common cause is airplane 
upset or pilot disorientation in instrument meteorological conditions.
    The FAA believes the prescriptive content of the current 
regulations, including the modified Pratt formula for gust loads, the 
descriptions of symmetrical maneuvers, checked and unchecked maneuvers, 
rolling maneuvers, and yawing maneuvers are more appropriate for 
inclusion in means of compliance. Applicants who wish to propose 
alternate design loading conditions should note that extensive data 
collection, testing, and evaluation may be necessary to substantiate 
their proposal.
v. Proposed Sec.  23.320, Ground and Water Load Conditions
    Proposed Sec.  23.320 would require an applicant to determine the 
loads resulting from taxi, take-off, landing, and ground handling 
conditions occurring in normal and adverse attitudes and 
configurations. Proposed Sec.  23.320 would capture the safety intent 
of current Sec. Sec.  23.471, Ground Loads--General; 23.473, Ground 
load conditions and assumptions; 23.477, Landing gear arrangement; 
23.479, Level landing conditions; 23.481, Tail down landing conditions; 
23.483, One-wheel landing conditions; 23.485, Side load conditions; 
23.493, Braked roll conditions; 23.497, Supplementary conditions for 
tail wheels; 23.499, Supplementary conditions for nose wheels; 23.505, 
Supplementary conditions for skiplanes; 23.507, Jacking loads; 23.509, 
Towing loads; 23.511, Ground load; unsymmetrical loads on multiple-
wheel units; 23.521, Water load conditions; 23.523, Design weights and 
center of gravity positions; 23.525, Application of loads; 23.527, Hull 
and main float load factors; 23.529 Hull and main float landing 
conditions; 23.531, Hull and main float takeoff condition; 23.533, Hull 
and main float bottom pressures; 23.535, Auxiliary float loads; 23.537, 
Seawing loads, and 23.753 Main float design.
    The current requirements set forth prescriptive requirements for 
determining takeoff and landing loads for airplanes operated on land, 
loads acting on floats and hulls for airplanes operated on water, as 
well as ground handling loads, including jacking and towing conditions. 
The current requirements also provide applicants with descriptions of 
the normal and adverse operating conditions and configurations for 
which applicants must determine ground and water loads.
    The FAA believes that the prescriptive descriptions of the loading 
conditions, normal and adverse conditions, and configurations are more 
appropriate for inclusion in means of compliance. Applicants who wish 
to propose alternate design loading conditions should note that 
extensive data collection, testing, and evaluation may be necessary to 
substantiate their proposal.
vi. Proposed Sec.  23.325, Component Loading Conditions
    Proposed Sec.  23.325 would require an applicant to determine the 
loads acting on each engine mount, flight control and high lift 
surface, and the loads acting on pressurized cabins. Proposed Sec.  
23.325 would capture the safety intent of current Sec. Sec.  23.345, 
High lift devices; 23.361, Engine torque; 23.363, Side load on engine 
mount; 23.365, Pressurized cabin loads; 23.371, Gyroscopic and 
aerodynamic loads; 23.373, Speed control devices; 23.391, Control 
surface loads; 23.393, Loads parallel to hinge line; 23.395, Control 
system loads; 23.397, Limit control forces and torques; 23.399, Dual 
control system; 23.405, Secondary control system; 23.407, Trim tab 
effects; 23.409, Tabs; 23.415, Ground gust conditions; 23.455, 
Ailerons; and 23.459, Special devices.
    The current part 23 regulations establish prescriptive requirements 
for determining loads acting on pressurized cabins, engine mounts and 
attachment structure, control surfaces, high lift surfaces, and speed 
control devices. The FAA believes that these prescriptive requirements 
in the current regulations are more appropriate for inclusion in means 
of compliance. However, in proposed Sec.  23.325, we have retained some 
of the prescriptive requirements for pressurized cabins, including 
descriptions of combined loading conditions and additional factors of 
safety for determining limit load.
vii. Proposed Sec.  23.330, Limit and Ultimate Loads
    Proposed Sec.  23.330 would describe how the applicant must 
determine the limit and ultimate loads associated with the structural 
design loads. Proposed Sec.  23.330 would capture the safety intent of 
current Sec. Sec.  23.301, Loads, paragraph (a); and 23.303, Factor of 
safety. These current sections specify factors of safety for 
determining limit and ultimate loads.
    Proposed Sec.  23.330 retains the current 1.5 safety factor for 
ultimate loads. This safety factor has resulted in a service history 
where structural failures due to applied static loads are rare. The FAA 
believes the 1.5 factor of safety is critical to maintaining the 
current level of safety.
    Proposed Sec.  23.330 would allow for additional special factors of 
safety to account for material and manufacturing variability. Proposed 
Sec.  23.330 would also allow alternate factors of safety when showing 
compliance with occupant protection loading conditions and when showing 
compliance with proposed Sec.  23.305.
viii. Proposed Sec.  23.400, Structural Strength
    Proposed Sec.  23.400 would require an applicant to demonstrate 
that the structure will support limit and ultimate loads. Proposed 
Sec.  23.400 would capture the safety intent of current Sec. Sec.  
23.305, Strength and deformation; and 23.307, Proof of structure.
    These current sections provide performance criteria for the 
structure when subjected to limit and ultimate loads. Proposed Sec.  
23.400 would retain these performance criteria and would require the 
applicant to demonstrate that the structure will meet these performance 
criteria. In this context, ``demonstrate'' means the applicant must 
conduct structural tests to show

[[Page 13476]]

compliance with the structural performance requirements, unless the 
applicant shows that a structural analysis is reliable and applicable 
to the structure. The FAA proposes not to retain the ``3 second'' rule 
in proposed Sec.  23.400. This prescriptive requirement in current 
Sec.  23.305(b) requires the applicant to demonstrate that the 
structure will support ultimate load for at least three seconds. The 
FAA believes this prescriptive requirement is a statement of physical 
principles and testing experience and is more appropriate for inclusion 
in means of compliance.
ix. Proposed Sec.  23.405, Structural Durability
    Proposed Sec.  23.405 would require an applicant to develop and 
implement procedures to prevent structural failures due to foreseeable 
causes of strength degradation, and to prevent rapid decompression in 
airplanes with a maximum operating altitude above 41,000 feet. Proposed 
Sec.  23.405 would also require an airplane to be reasonably capable of 
continued safe flight and landing with foreseeable structural damage 
caused by high-energy fragments from an uncontained engine or rotating 
machinery failure. Proposed Sec.  23.405 would capture the safety 
intent of current Sec. Sec.  23.365(e), Pressurized cabin loads; 
23.571, Metallic pressurized cabin structures; 23.572, Metallic wing, 
empennage, and associated structures; 23.573, Damage tolerance and 
fatigue evaluation of structure; 23.574, Metallic damage tolerance and 
fatigue evaluation of commuter category airplanes; 23.575, Inspections 
and other procedures; and 23.627, Fatigue strength.
    Proposed Sec.  23.405(a) would require an applicant to develop and 
implement procedures to prevent structural failures. These procedures 
may include the safe-life, damage tolerance, or fail-safe design 
approaches described in the current regulations. An applicant can 
propose other means of compliance, but these means must provide at 
least the same level of safety as current means of compliance. Any new 
means of compliance must consider the airplane design, manufacturing, 
operational, and maintenance environments. The FAA proposes 
implementing these procedures by including them in the airplane's 
Instructions for Continued Airworthiness.
    The procedures must be able to prevent structural failures due to 
foreseeable causes of strength degradation. Foreseeable causes include 
fatigue and corrosion in metallic structures, and fatigue, 
delaminations, disbonds, and impact damage in composite structures. New 
material systems or structural designs, such as additive manufacturing, 
may introduce new causes of strength degradation and may require 
development of new and unique procedures to prevent structural 
failures.
    The current part 23 regulations use prevention of catastrophic 
failures as the safety intent of the regulations. The word 
``catastrophic'' is used throughout the current regulations, current 
policy, and guidance material, especially in context of system safety 
analysis. To avoid any potential conflict over the meaning of 
``catastrophic,'' proposed Sec.  23.405(a) would specify the 
consequences we want to prevent. These consequences include the obvious 
performance criteria for prevention of serious injuries, fatalities, or 
hull loss of the airplane.
    The FAA also wants to prevent extended periods of operations with 
reduced safety margins in those structural components whose failure 
could result in serious injuries, fatalities, or hull loss. One 
situation that can result in reduced safety margins is fail-safe 
design. The FAA has identified potential shortcomings in fail-safe 
designs, including an applicant's difficulty to anticipate all possible 
failure scenarios and ensure that all structural failures would be 
immediately obvious and corrected before further flight. The concept of 
failures being obvious and repaired before further flight is basic to 
the successful implementation of a fail-safe design. This scenario 
could allow operation for extended periods with a passive structural 
failure and reduced safety margins. If an applicant chooses fail-safe 
design as a means of compliance, an applicant would have to ensure that 
the structure was not operating for extended periods with reduced 
safety margins. An applicant may be able to apply safe-life or damage 
tolerance principles to ensure that fail-safe structure maintains the 
required safety margins without extended periods of operation with 
reduced safety margins through life limits or damage tolerance based 
inspections.
    Proposed Sec.  23.405(b) would capture the safety intent of current 
Sec.  23.365(e), requiring the applicant to design the structure for 
sudden loss of pressurization after the failure of a door or window in 
pressurized compartments. Proposed Sec.  23.405(c) incorporates the 
safety intent of current Sec.  23.571(d). Our intention is that the 
damage tolerance methodology would remain the accepted means of 
compliance. The FAA views damage tolerance as necessary since current 
Sec.  23.571(d) and proposed Sec.  23.405(c) require the applicant to 
assume that structural damage exists in the pressurized cabin. However, 
proposed Sec.  23.405(c) would allow for other means of compliance as 
long as serious injuries and fatalities will be prevented. Examples of 
other means of compliance might include requiring pilots and occupants 
to use oxygen masks or wear pressurized flight suits when operating 
above 41,000 feet (12,497 meters). This means of compliance could be 
acceptable in certain airplane designs, such as two-seat jet trainers.
    Proposed Sec.  23.405(d) would capture the safety intent of current 
Sec.  23.903(b)(1) to minimize hazards to the airframe resulting from 
turbine engine rotorburst. The FAA would move the structural portion of 
the rotorburst evaluation from current Sec.  23.903(b)(1) to proposed 
Sec.  23.405(d) to ensure all structural requirements are contained in 
subpart C and to avoid potential confusion over the structural 
rotorburst requirements in part 23.
    Proposed Sec.  23.405(d) would require an applicant to show that 
the design of the structure would provide sufficient structural 
capability to allow continued safe flight and landing with foreseeable 
structural damage caused by high energy fragments from an uncontained 
engine or rotating machinery failure. The FAA recognizes that some 
high-energy fragment events may result in catastrophic failures that 
may not be avoidable and that complete elimination of the hazards 
resulting from high energy fragment events may not be possible.
    An applicant would be required to address other sources of high 
energy rotating machinery fragments in the proposed structural 
rotorburst requirements. Our intent is to ensure an adequate regulatory 
framework for applications of electrical propulsion systems and other 
unique and novel approaches to propulsion, which may release high-
energy fragments.
    Applicants who have shown compliance with current Sec.  
23.903(b)(1) would be able to show compliance with proposed Sec.  
23.405(d). Applicants should note that previous certification programs 
with turbine engine installations have been able to show that the 
airplane structure is capable of continued safe flight and landing 
following a rotorburst event. AC 23-13A, Fatigue, Fail-Safe, and Damage 
Tolerance Evaluation of Metallic Structure for Normal, Utility, 
Acrobatic, and Commuter Category airplanes, provides guidance on the 
required structural evaluation.

[[Page 13477]]

x. Proposed Sec.  23.410, Aeroelasticity
    Proposed Sec.  23.410 would require an airplane to be free from 
flutter, control reversal, and divergence at all speeds within and 
sufficiently beyond the structural design envelope, for any 
configuration and condition of operation, accounting for critical 
degrees of freedom, and any critical failures or malfunctions. Proposed 
Sec.  23.410 would also require an applicant to establish tolerances 
for all quantities that affect flutter.
    Proposed Sec.  23.410 would capture the safety intent of the 
current Sec. Sec.  23.629, Flutter; 23.677, Trim systems, paragraph 
(c); and 23.687, Spring devices, in part. Specifically, proposed Sec.  
23.410 would address the safety intent of these rules by requiring 
freedom from flutter, control reversal, and divergence, while 
accounting for all speeds, configurations, modes, and failures, and to 
establish tolerances on anything affecting flutter. The current Sec.  
23.629(a) states that freedom from flutter, control reversal, and 
divergence must be shown by the methods of Sec.  23.629(b) and (c) or 
(d). These paragraphs are prescriptive in nature and some portions are 
applicable only to very specific types of designs and include speed 
limitations. Therefore, these paragraphs are more appropriate as means 
of compliance.
    The current Sec.  23.629(e) requires the evaluation of whirl mode 
flutter. Since this is another flutter mode, it must be accounted for 
when an airplane is determined to be free from flutter. The current 
Sec.  23.629(f), (g), (h), and (i) provide instructions on how to 
evaluate (1) certain airplane design types, (2) designs employing 
certain methods (fail-safe or damage tolerant), or (3) airplanes 
incorporating design modifications. The current Sec.  23.677(c) 
requires either that the tab be balanced or that the tab controls be 
irreversible. Additionally, it requires that irreversible tab systems 
have adequate rigidity and reliability. These are very specific design 
solutions for ensuring freedom from flutter. The current Sec.  23.687 
requires that the reliability of spring devices used in control systems 
be established by tests unless its failure would not cause flutter. 
This is a method of compliance to ensure freedom from flutter. All of 
these current requirements are more appropriate as means of compliance 
because they describe how to ensure freedom from flutter, control 
reversal, and divergence. They are not the safety intent, but just one 
method to achieve the safety intent. As such, they serve only specific 
designs utilizing current methods, and may or may not be adequate for 
innovative designs or accommodate new analytical methods or testing 
techniques.
xi. Proposed Sec.  23.500, Structural Design
    Proposed Sec.  23.500 would require an applicant to design each 
part, article, and assembly for the expected operating conditions of 
the airplane. Proposed Sec.  23.500 would require the design data to 
adequately define the part, article, or assembly configuration, its 
design features, and any materials and processes used. Proposed Sec.  
23.500 would require an applicant to determine the suitability of each 
design detail and part having an important bearing on safety in 
operations. Proposed Sec.  23.500 would also require the control system 
to be free from--
     Jamming;
     Excessive friction, and
     Excessive deflection when the control system and its 
supporting structure are subjected to loads corresponding to the limit 
airloads when the primary controls are subjected to the lesser of the 
limit airloads or limit pilot forces and when the secondary controls 
are subjected to loads not less than those corresponding to maximum 
pilot effort.
    Proposed Sec.  23.500 would capture the safety intent of the 
current Sec. Sec.  23.601, Design and Construction--General; 23.603, 
Materials and workmanship, paragraph (b); 23.671, Control Systems--
General, paragraph (a); 23.683, Operation tests; 23.685, Control system 
details; 23.687, Spring devices, in part; and 23.689, Cable systems. 
These current requirements explain methods and techniques to ensure an 
adequate design. The proposed rule would require an applicant to 
produce an adequate design without specifying how. The prescriptive 
language within these current sections noted above, are more 
appropriate for a means of compliance.
xii. Proposed Sec.  23.505, Protection of Structure
    Proposed Sec.  23.505 would require an applicant to protect each 
part of the airplane, including small parts such as fasteners, against 
deterioration or loss of strength due to any cause likely to occur in 
the expected operational environment. Proposed Sec.  23.505 would 
require each part of the airplane to have adequate provisions for 
ventilation and drainage and would require an applicant to incorporate 
a means into the airplane design to allow for required maintenance, 
preventive maintenance, and servicing.
    Proposed Sec.  23.505 would capture the safety intent of the 
current Sec. Sec.  23.607, Fasteners; 23.609, Protection of structure; 
and 23.611, Accessibility. These current requirements explain methods 
and techniques to ensure an adequate design. This proposed rule would 
require the applicant to produce an adequate design without specifying 
how to accomplish it. The prescriptive language within these current 
sections is more appropriate as a means of compliance.
xiii. Proposed Sec.  23.510, Materials and Processes
    Proposed Sec.  23.510 would require an applicant to determine the 
suitability and durability of materials used for parts, articles, and 
assemblies, the failure of which could prevent continued safe flight 
and landing, while accounting for the effects of likely environmental 
conditions expected in service. Proposed Sec.  23.510 would require the 
methods and processes of fabrication and assembly used to produce 
consistently sound structures and, if a fabrication process requires 
close control to reach this objective, an applicant would have to 
perform the process under an approved process specification. 
Additionally, proposed Sec.  23.510 would require an applicant to 
justify the selected design values to ensure material strength with 
probabilities, account for--
     The criticality of the structural element; and
     The structural failure due to material variability, unless 
each individual item is tested before use to determine that the actual 
strength properties of that particular item would equal or exceed those 
used in the design, or the design values are accepted by the 
Administrator.
    Proposed Sec.  23.510 would require a determination of required 
material strength properties to be based on sufficient tests of 
material meeting specifications to establish design values on a 
statistical basis. Proposed Sec.  23.510 would also require an 
applicant to determine the effects on allowable stresses used for 
design if thermal effects were significant on an essential component or 
structure under normal operating conditions.
    Proposed Sec.  23.510 would capture the safety intent of the 
current Sec. Sec.  23.605, Fabrication methods and 23.613, Material 
strength properties and design values. These current requirements 
explain methods and techniques to ensure adequate materials and process 
controls. This proposed rule would require the applicant to ensure the 
resulting materials and processes are adequate without specifying how. 
The prescriptive language within the current

[[Page 13478]]

sections is more appropriate as a means of compliance.
xiv. Proposed Sec.  23.515, Special Factors of Safety
    Proposed Sec.  23.515 would require an applicant to determine a 
special factor of safety for any critical design value that was 
uncertain, used for a part, article, or assembly likely to deteriorate 
in service before normal replacement, or subject to appreciable 
variability because of uncertainties in manufacturing processes or 
inspection methods. Proposed Sec.  23.515 would require an applicant to 
determine a special factor of safety using quality controls and 
specifications that accounted for each structural application, 
inspection method, structural test requirement, sampling percentage, 
and process and material control. Proposed Sec.  23.515 would require 
an applicant to apply any special factor of safety in the design for 
each part of the structure by multiplying each limit load and ultimate 
load by the special factor of safety.
    Proposed Sec.  23.515 would capture the safety intent of current 
Sec. Sec.  23.619, Special factors; 23.621, Casting factors; 23.623, 
Bearing factors; 23.625, Fitting factors; 23.657, Hinges; 23.681(b), 
Limit load static test (in part); and 23.693, Joints. These current 
requirements explain methods and techniques to ensure adequate special 
factors are used and the proposed rule would simply require the 
applicant to determine and apply adequate special factors without 
specifying what these are. The prescriptive language within the current 
sections is more appropriate as a means of compliance.
xv. Proposed Sec.  23.600, Emergency Conditions
    Proposed Sec.  23.600 would require the airplane, even if damaged 
in emergency landing conditions, to provide protection to each occupant 
against injury that would preclude egress. Proposed Sec.  23.600 would 
require the airplane to have seating and restraints for all occupants, 
consisting of a seat, a method to restrain the occupant's pelvis and 
torso, and a single action restraint release, which meets its intended 
function and does not create a hazard that could cause a secondary 
injury to an occupant. Proposed Sec.  23.600 would require the airplane 
seating, restraints, and cabin interior to account for likely flight 
and emergency landing conditions. Additionally, they could not prevent 
occupant egress or interfere with the operation of the airplane when 
not in use.
    Proposed Sec.  23.600 would require each baggage and cargo 
compartment be designed for its maximum weight of contents and for the 
critical load distributions at the maximum load factors corresponding 
to the determined flight and ground load conditions. Proposed Sec.  
23.600 would also require each baggage and cargo compartment to have a 
means to prevent the contents of the compartment from becoming a hazard 
by impacting occupants or shifting, and to protect any controls, 
wiring, lines, equipment, or accessories whose damage or failure would 
affect operations.
    Proposed Sec.  23.600 would capture the safety intent of current 
Sec. Sec.  23.561, Emergency Landing Conditions--General; 23.562, 
Emergency landing dynamic conditions; 23.785, Seats, berths, litters, 
safety belts, and shoulder harnesses; and 23.787, Baggage and cargo 
compartments. The prescriptive language within these current sections 
are more appropriate as a means of compliance, and thus would allow 
flexibility for new technology to be available in new part 23 airplanes 
in a timely manner.
    Occupant safety for aviation has progressed incrementally over the 
years. This has resulted in rulemaking that has enhanced safety for 
individual system components, but not in an integrated fashion. 
Modeling and analysis techniques have matured to a point that may allow 
evaluation of more crash scenarios and crashworthiness components as an 
integrated system. The FAA has relied on many industry studies to 
develop current occupant safety rules. These studies evaluated 
characteristics of actual accidents, full-scale aircraft drop testing, 
and dynamic seat testing on a sled. When dynamic seat testing began, 
determination of an adequate generic floor impulse that represented a 
survivable aircraft crash was established. As an alternative to current 
crashworthiness requirements, the proposed rule would allow for 
evaluation of the conditions of likely impacts, assessment of vehicle 
response, and ultimately, evaluation of occupant reaction to vehicle 
impact and vehicle response.
    Technology used in aviation crashworthiness, in a large part, has 
come from the automotive industry. The automotive industry has analyzed 
crashworthiness components as a system for many years. The automotive 
industry generally has a more developed crashworthiness analysis 
capability than that used in the aviation industry. This advanced 
crashworthiness analysis capability has evolved primarily because of 
the--
     Public expectation for automobile safety;
     Higher general public likelihood and exposure to 
automobile accidents; and
     High automobile production rates allow for multiple actual 
full-vehicle crash tests that result in very accurate crash impulse 
data from the outer surface of the vehicle all the way to the occupant.
    Because of these facts, automotive designers know accurate impulses 
and the specific vehicle response for impact conditions. Furthermore, 
this data can be extrapolated to consider many more accident scenarios. 
Automotive safety requirements progressively add new impact scenario 
requirements and enhanced impulse magnitudes, thus requiring more 
industry innovation. This innovation has enabled rapid advances in 
automotive occupant protection systems.
    Automotive safety begins at the outside of the vehicle, evaluating 
the entire system's response. In contrast, aircraft manufacturers have 
used essentially the same generic designed pulse imparted at the cabin 
floor for the last 25 years. The same impulse applies to all GA 
airplanes independent of the structure below the cabin floor and the 
aircraft's stall speed, unless the stall speed is greater than 61 
knots. Determining airplane crashworthiness is a more complex process 
than determining automotive crashworthiness because of higher impact 
speeds, lighter weight structures, and the effect of the third 
dimension of altitude on the aircraft. Dynamic seat testing has 
improved crashworthiness in aviation; however, the FAA believes that 
newer means of evaluating the full aircraft response to crash 
conditions via modeling, newer materials, and new technologies promise 
to offer improved features, evaluation, and accuracy that would 
facilitate consideration of more crash scenarios and evaluation of more 
variables that could improve survivability.
    The NTSB produced a series of reports, called the General Aviation 
Crashworthiness Project,\21\ in the 1980s that evaluated over 21,000 GA 
airplane crashes that occurred between 1972 and 1981. The NTSB 
evaluated airplane orientation, impact magnitudes, and survival rates 
and factors on many of these accidents in order to provide information 
to support changes in crashworthiness design standards for seating and 
restraint systems in GA airplanes. These reports also established

[[Page 13479]]

conditions approximating survivable accidents, and categorized factors 
that would have the largest impact on safety. These reports further 
illuminated the various crashworthiness systems and their respective 
impact to overall safety. Amendment 23-36 (53 FR 30802, August 15, 
1988), to part 23 referenced these reports for dynamic seats but did 
not adopt a systems-approach to evaluating crashworthiness of an 
airplane design.
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    \21\ See www.regulations.gov (Docket #FAA-2015-1621).
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    The NTSB reports identified several factors that would enhance 
safety. All of these factors working together as a system should result 
in a safer airplane. However, the assessment indicated that shoulder 
harnesses offer the fastest individual improvement for safety. The FAA 
codified the shoulder harnesses requirement in amendments 23-19 (42 FR 
20601, June 16, 1977) and 23-32 (50 FR 46872, November 13, 1985), for 
newly manufactured airplanes. The FAA also issued policy statement ACE-
00-23.561-01,\22\ Methods of Approval of Retrofit Shoulder Harness 
Installations in Small Airplanes, to streamline the process for 
retrofitting older airplanes.
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    \22\ See www.regulations.gov (Docket #FAA-2015-1621).
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    Survivable volume is another critical factor to survival. 
Survivable volume is the ability of the airframe to protect the 
occupants from external intrusion or cabin crushing during and after 
the accident sequence. There were several observed accidents in the 
NTSB study where conventional aircraft construction simply crushed an 
otherwise restrained occupant. Crashworthiness regulations have never 
included survivable volume as a factor, except for aircraft turnover. 
Airplane designs should provide the space needed for the protection and 
restraint of the occupants. A compromised survivable volume could cause 
occupant impact with objects in the cabin. This is one of the first 
steps in the analysis of airplane crashworthiness.
    Additional data from the NTSB General Aviation Crashworthiness 
Project suggested that energy-absorbing seats that protect the occupant 
from vertical loads could enhance occupant survivability and work to 
prevent serious injury, thereby enhancing odds for egress and 
preventing many debilitating long-term injuries. The FAA established 
dynamic seat testing requirements in amendment 23-36 for airplanes 
certificated under part 23. Energy absorbing seats benefit a smaller 
portion of accident occupants because accident impacts with larger 
vertical components tend to reduce occupant survival odds. Energy 
attenuation from vertical forces, both static and dynamic, has been 
important to crashworthiness regulations within the past 25 years. Seat 
deformation throughout the emergency landing sequence is acceptable if 
the load path through attachment, seat, and restraint remains 
continuous. Coupling the seat performance to the rest of the airframe 
response is important to the enhancement and understanding of occupant 
survivability. The FAA believes that allowing designers to consider a 
particular airframe's unique deformation in a crash, the designers can 
create a safer cabin for the occupants. Using unique airframe 
deformations would result in more accurate accident floor impulses and 
may allow evaluation of crash impulses in multiple directions; instead 
of only two directions considered in current certification.
    Occupant restraints must maintain integrity, stay in place on the 
occupant throughout the event, properly distribute loads on the 
occupant, and restrain the occupant by mitigating interaction with 
other items in the cabin. Restraints originally were comprised of lap 
belts. Shoulder harnesses were later required as discussed above. Newer 
technology that enhances or supplements the performance of restraints, 
like airbags and consideration of items in the cabin that the occupant 
might impact, are now being considered for inclusion in designs. The 
use of airbags has greatly increased passenger safety in automobiles, 
which offer protection in much more severe impacts and in impacts from 
multiple directions, and could be a viable option for airplanes as 
well.
    Seat retention in airplanes is a factor identified as another basic 
building block for crashworthiness. The NTSB reports shows more than a 
quarter of otherwise-survivable accidents included instances where the 
seats broke free at the attachment to the airplane, resulting in 
fatalities or serious injuries. Dynamic seat testing requirements 
address the ability of seat assemblies to remain attached to the floor, 
even when the floor shifts during impact. Pitching and yawing of the 
seat tracks during dynamic seat tests demonstrates the gimbaling and 
flexibility of the seat.
    All of the aforementioned safety considerations must work together 
to enhance occupant safety and survivability. The FAA believes that 
evaluating occupant safety, as a whole system, would allow for a better 
understanding of vehicle performance in an emergency landing, enabling 
the incorporation of innovative technology. The transportation industry 
has made significant progress with energy absorbing seats and restraint 
technology. The FAA believes enhanced cabin strength that improves 
survivable volume, coupled with better restraint technology and refined 
energy absorbing seats, would be key factors in improving expansion of 
the survivable accident envelope. These factors and additional 
considerations were included in the Small Airplane Crashworthiness 
Design Guide.\23\ This guide was prepared for the Advanced General 
Aviation Transports Experiments and the National Aerospace and Space 
Administration and addresses the concept of designing crashworthiness 
into an airplane design as a system.
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    \23\ See www.regulations.gov (Docket #FAA-2015-1621).
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    In order to evaluate an accident from an occupant's perspective, 
the emergency landing condition must first be defined, starting with 
the conditions external to the aircraft. In most survivable accidents, 
the pilot is able to maintain control of the aircraft prior to impact. 
Accidents where the airplane impacts the ground out of control are 
typically much less survivable. Speed and impact orientation are 
significant factors in crash survivability. Therefore, considerations 
for impact beyond a controllable impact are beyond the scope of these 
proposed regulations. The slowest forward speed that any fixed wing 
airplane can fly is its stall speed. This stall speed can vary with 
airplane configuration and weight, but represents the most universal 
parameter for impact speed and energy attenuation at impact. For this 
reason, stall speed is the starting point for consideration of expected 
impact conditions.
    Orientation of impact can vary with pitch, yaw, terrain angle, and 
angle of flight path and becomes dynamic as the pilot loses control 
effectiveness at stall. The result is the airplane impact angle can 
result in a combination of horizontal and vertical loads and impulses 
that vary widely. Angle of impact, the line of the center of mass with 
respect to the angle of the impact surface, can also affect the amount 
of energy absorbed or transmitted to the occupant.
    An accident impulse is a dynamic event that rapidly loads and 
unloads the structure. Dynamic impacts accurately represent the impact 
event, often including load levels far surpassing the static load 
requirements. Dynamic testing is also subject to a wide variation of 
results due to the unpredictable dynamic responses of varying

[[Page 13480]]

construction methods and materials, resulting in complicated modeling 
and analysis. This contrasts with static load tests that load the 
structure slowly, maintain that load at high levels, are generally 
simpler, and often provide adequate demonstration of part strength. 
Static analysis is generally more reliable with both testing and 
modeling; however, it does not capture the nature of rapid loading. 
Some combination of dynamic and static testing allows for the best 
understanding of airplane behavior during an accident.
    Compliance with the proposed rule could be shown using conventional 
means of compliance like dynamic testing of seats, and static testing 
of other components using the prescriptive methods contained in the 
current part 23. Alternative compliance methods could include analysis 
or modeling supported by testing using an airframe coupled with the 
airplane's performance envelope, viewing the entire interaction of 
ground, airplane, and occupant, thus using a more complete systemic 
approach to achieve improved protection.
    Proposed Sec.  23.600(a) is intended to provide structural 
performance that protects the occupant during an emergency landing 
while accounting for only static loads and assuming all safety 
equipment is in use. The proposed section would capture the safety 
intent of the current Sec.  23.561. As noted earlier, static loads are 
generally lower than peak dynamic loads; however, they may offer a 
more-easily predictable loading condition and are generally of longer 
duration such that the structure can fully react to the load. The 
landing conditions should consider possible accident sequence variables 
at impact, including restraint of items of mass within the cabin, 
directions of loading along or about the three axes, and airframe 
response with respect to the occupants and effects of airframe 
deflection during an emergency landing. Effects of emergency landing on 
the airplane should also be considered to include the effect of 
airframe damage and how static loads would affect egress and survivable 
cabin volume. Items of mass within the cabin and rear mounted engines 
have also been traditionally considered using even higher static loads 
as an additional factor of safety to ensure that these items of mass 
are restrained and would be among the last items to come free in an 
accident.
    Proposed Sec.  23.600(b) is intended to provide boundary conditions 
for the emergency landing sequence for both static and dynamic load 
considerations. The proposed section would capture the safety intent of 
the current Sec. Sec.  23.561 and 23.562. The airplane stall speed 
limits the maximum forward impact speed. The emergency landing 
condition assumes the pilot maintains airplane control at or near final 
impact, thereby limiting impact velocity.
    Proposed Sec.  23.600(c) would capture the survivability factors 
for the occupant in the cabin during the emergency landing sequence and 
would capture the safety intent of current Sec.  23.562. These factors 
include proper use and loading of seats and restraints, and the 
interaction of the occupants with each other and the cabin interior. 
Survivability is determined upon the occupant's interaction with the 
interior, seat, and restraints, and bounded by established human injury 
criteria.
    Proposed Sec.  23.600(d) would provide the framework for seats and 
occupant restraints and would require simplified seat and restraint 
requirements for all occupants. This proposed section would capture the 
safety intent of current Sec.  23.785.
    Proposed Sec.  23.600(e) would establish requirements for baggage 
and cargo compartments and the restraint of contents. The proposed 
section would capture the safety intent of current Sec.  23.787.
xvi. Current Subpart C Regulations Relocated to Other Proposed Subparts
    As discussed, the FAA proposes removing current Sec. Sec.  23.561, 
23.562, 23.785, and 23.787. Also, this proposal would consolidate the 
safety intent of these crashworthiness regulations in proposed Sec.  
23.600.
4. Subpart D--Design and Construction
a. General Discussion
    The FAA proposes restructuring current subpart D to retain the 
requirements for flight control systems, along with their attachment to 
the structure and landing gear, and occupant safety other than 
structural requirements. The FAA proposes to align structural 
requirements, found in current Sec. Sec.  23.601 through 23.659, to 
proposed subpart C. Aspects that directly affected the pilot's 
interface with the airplane, such as the throttle shape, would be 
relocated to proposed Sec.  23.1500, Flightcrew Interface.
    The FAA also proposes, in those sections where there are 
requirements specific to the current commuter category, to use 
certification level 4. In those sections where there are current 
requirements specific to multiengine jets over 6,000 pounds, the FAA 
proposes requirements for certification level 3, high-speed multiengine 
airplanes as discussed earlier in this proposal. Refer to appendix 1 of 
this preamble for a cross-reference table detailing how the current 
regulations are addressed in the proposed part 23 regulations.
    The subpart D organization was more complex than other subparts due 
to the relocation and removal of many requirements at the sub-paragraph 
level. To reduce confusion, the specific discussion of subpart D 
changes is shown in a cross reference table at the end of the specific 
discussion section below rather than the Relocation and Removal 
paragraphs in other subparts.
b. Specific Discussion of Changes
i. Proposed Sec.  23.700, Flight Controls Systems
    Proposed Sec.  23.700 would require an applicant to design airplane 
flight control systems to prevent major, hazardous, and catastrophic 
hazards. Proposed Sec.  23.700 would require an applicant to design 
trim systems to prevent inadvertent, incorrect, or abrupt trim 
operation. In addition, proposed Sec.  23.700 would require an 
applicant to design trim systems to provide a means to indicate--
     The direction of trim control movement relative to 
airplane motion;
     The trim position with respect to the trim range;
     The neutral position for lateral and directional trim; and
     For all airplanes except simple airplanes, the range for 
takeoff for all applicant requested center of gravity ranges and 
configurations.
    Proposed Sec.  23.700 would also require an applicant to design 
trim systems to provide control for continued safe flight and landing 
when any one connecting or transmitting element in the primary flight 
control system failed, except for simple airplanes. Additionally, 
proposed Sec.  23.700 would require an applicant to design trim systems 
to limit the range of travel to allow safe flight and landing, if an 
adjustable stabilizer is used.
    Furthermore, proposed Sec.  23.700 would require the system for an 
airplane equipped with an artificial stall barrier system to prevent 
uncommanded control or thrust action and provide for a preflight check. 
The FAA also proposes requiring an applicant seeking certification of a 
certification level 3 high-speed or certification level 4 airplane to 
install a takeoff warning system on the airplane, unless the applicant 
demonstrates that the airplane, for each configuration, could takeoff 
at the limits of its trim and flap ranges.
    Proposed Sec.  23.700(b)(3) would also allow an exception for 
simple airplanes

[[Page 13481]]

from the requirement to provide control for continued safe flight and 
landing when any one connecting or transmitting element in the primary 
control system fails. This would provide a level of safety equivalent 
to that specified in EASA's CS-VLA. Last, proposed Sec.  23.700(d) 
would maintain the level of safety in the current requirements for a 
takeoff warning system.
    Proposed Sec.  23.700 would capture the safety intent of current 
Sec. Sec.  23.677, Trim systems, paragraphs (a), (b), and (d); 23.689, 
Cable systems, paragraphs (a) and (f); 23.691, Artificial stall barrier 
system, paragraphs (a), (b), (d), (e) and (f); 23.697, Wing flap 
controls, paragraphs (a); and 23.703, Takeoff warning system, 
paragraphs (a) and (b). This proposed section would apply to the 
function, usability, and hazard levels of all mechanical, electrical, 
or electronic control systems. The certification levels proposed in 
this NPRM would be incorporated into the mechanical, electrical, or 
electronic control systems to maintain the differences in airplanes 
certificated under part 23 (i.e., weight and powerplant.)
ii. Proposed Sec.  23.705, Landing Gear Systems
    Proposed Sec.  23.705 would require an airplane's landing gear and 
retracting mechanism be able to withstand operational and flight loads. 
Proposed Sec.  23.705 would require an airplane with retractable 
landing gear to have a positive means to keep the landing gear extended 
and a secondary means for extending the landing gear that could not be 
extended using the primary means. Proposed Sec.  23.705 would also 
require a means to inform the pilot that each landing gear is secured 
in the extended and retracted positions. Additionally, proposed Sec.  
23.705 would require an airplane, except for airplanes intended for 
operation on water, with retractable landing gear to also have a 
warning to the pilot if the thrust and configuration is selected for 
landing and yet the landing gear is not fully extended and locked.
    Furthermore, if the landing gear bayis used as the location for 
equipment other than the landing gear, proposed Sec.  23.705 would 
require that equipment be designed and installed to avoid damage from 
tire burst and from items that may enter the landing gear bay. Proposed 
Sec.  23.705 would also require the design of each landing gear wheel, 
tire, and ski account for critical loads and would require a reliable 
means of stopping the airplane with kinetic energy absorption within 
the airplane's design specifications for landing. For certification 
level 3 high-speed multiengine and certification level 4 multiengine 
airplanes, proposed Sec.  23.705 would require the braking system to 
provide kinetic energy absorption within the design of the airplane 
specifications for rejected takeoff as the current rules do for 
multiengine jets over 6,000 pounds and commuter category airplanes.
    Proposed Sec.  23.705 would capture the safety intent of current 
Sec. Sec.  23.729, Landing gear extension and retraction system, 
paragraphs (a), (b), (c), and (e); 23.731, Wheels; 23.733, Tires, 
paragraph (a); 23.735, Brakes, paragraphs (a), (b), and (e); 23.737, 
Skis. The FAA proposes to combine the fixed and retractable landing 
gear systems into the proposed section, which would apply to the 
function, usability, and hazard levels of all mechanical, electrical, 
or electronic landing gear systems.
iii. Proposed Sec.  23.710, Buoyancy for Seaplanes and Amphibians
    Proposed Sec.  23.710 would require airplanes intended for 
operations on water to provide buoyancy of 80 percent in excess of the 
buoyancy required to support the maximum weight of the airplane in 
fresh water. Proposed Sec.  23.710 would also require airplanes 
intended for operations on water to have sufficient watertight 
compartments so the airplane will stay afloat at rest in calm water 
without capsizing if any two compartments of any main float or hull are 
flooded.
    Proposed Sec.  23.710 would capture the safety intent of current 
Sec. Sec.  23.751(a), Main float buoyancy; 23.755, Hulls; and 23.757, 
Auxiliary floats. The FAA proposes combining the floats or hulls 
landing gear systems into the proposed section and having it apply to 
the function, usability, and hazard levels of hulls and floats. The 
existing rule requires at least four watertight compartments of 
approximately equal volume, which the FAA proposes to remove because 
they are specific design requirements and are addressed in the proposed 
performance-based requirements.
    To encourage the installation of buoyancy systems with new safety 
enhancing technology and streamlining the certification process, the 
FAA proposes removing most of the current prescriptive requirements and 
the detailed means of compliance for these requirements from the 
current part 23 and replacing them with performance-based regulations. 
The FAA expects the current means of compliance would continue to be 
used for the traditional airplane designs under part 23.
iv. Sec.  23.750, Means of Egress and Emergency Exits
    Proposed Sec.  23.750 would require the airplane cabin exit be 
designed to provide for evacuation of the airplane within 90 seconds in 
conditions likely to occur, excluding ditching, following an emergency 
landing. For ditching, proposed Sec.  23.750 would require the cabin 
exit for all certification levels 3 and 4 multiengine airplanes be 
designed to allow evacuation in 90 seconds. Proposed Sec.  23.750 would 
require each exit to have a simple and obvious means, marked inside and 
outside the airplane, to be opened from both inside and outside the 
airplane, when the internal locking mechanism is in the locked 
position.
    Proposed Sec.  23.750 would also require airplane evacuation paths 
to protect occupants from serious injury from the propulsion system, 
and require that doors, canopies, and exits be protected from opening 
inadvertently in flight. Proposed Sec.  23.750 would preclude each exit 
from being obstructed by a seat or seat back, unless the seat or seat 
back could be easily moved in one action to clear the exit. Proposed 
Sec.  23.750 would also require airplanes certified for aerobatics to 
have a means to exit the airplane in flight.
    Proposed Sec.  23.750 would capture the safety intent of current 
Sec. Sec.  23.783, Doors, paragraphs (a), (b), (c), and (d); 23.791, 
23.803, Emergency evacuation, paragraph (a); 23.805, Flightcrew 
emergency exits; 23.807, Emergency exits except paragraphs (a)(3), 
(b)(1), (c), (d)(1) and (d)(4); 23.811, Emergency exit marking; 23.812, 
Emergency lighting; 23.813, Emergency exit access, paragraph (a); and 
23.815, Width of aisle; and CS-VLA-783, Exits. This proposed rule would 
incorporate the requirements for all door and emergency exits and 
remove specified design solutions and means of compliances.
    To encourage the installation of egress and emergency exits with 
new safety enhancing technology and streamline the certification 
process, the FAA proposes removing most of the current prescriptive 
requirements and the detailed means of compliance for these 
requirements from the current part 23. The FAA expects that the current 
prescriptive means of compliance would continue to be used for 
traditional part 23 airplane designs.
    The FAA would continue to accept an airplane designed to meet these 
prescriptive design constraints as means of compliance to meet the 
proposed performance standard. However, if an airplane did not meet the 
prescriptive design constraints, the applicant could

[[Page 13482]]

propose its own means of compliance to show compliance with the 
proposed performance standard. Historically, the FAA has accepted an 
emergency evacuation demonstration in less than 90 seconds as an ELOS 
for airplanes that did not meet the prescriptive design requirements in 
the current part 23 regulations. AC 20-118A, Emergency Evacuation 
Demonstration, contains an acceptable means of compliance for the 90-
second requirement for emergency evacuation.
v. Proposed Sec.  23.755, Occupant Physical Environment
    Proposed Sec.  23.755 would require an applicant to design the 
airplane to allow clear communication between the flightcrew and 
passengers and provide a clear, sufficiently undistorted external view 
to enable the flightcrew to perform any maneuvers within the operating 
limitations of the airplane. Proposed Sec.  23.755 would also require 
an applicant to design the airplane to protect the pilot from serious 
injury due to high energy rotating failures in systems and equipment, 
and protect the occupants from serious injury due to damage to 
windshields, windows, and canopies.
    Additionally, proposed Sec.  23.755 would require, for 
certification level 4 airplanes, each windshield and its supporting 
structure directly in front of the pilot to withstand the impact 
equivalent of a two-pound bird at maximum approach flap airspeed and 
allow for continued safe flight and landing after the loss of vision 
through any one panel.
    Furthermore, proposed Sec.  23.755 would require any installed 
oxygen system to include a means to determine whether oxygen is being 
delivered and a means for the flightcrew to turn on and shut off the 
oxygen supply, and the ability for the flightcrew to determine the 
quantity of oxygen available. Proposed Sec.  23.755 would also require 
any installed pressurization system to include a pressurization system 
test and a warning if an unsafe condition exists.
    Proposed Sec.  23.755 would capture the safety intent of current 
Sec. Sec.  23.771, Pilot compartment, paragraphs (b) and (c); 23.775, 
Windshields and windows, paragraphs (a), (b), (c), (d), and (h); 
23.831, Ventilation; 23.841, Pressurized cabins, paragraphs (a), 
(b)(6), (c) and (d); 23.843, Pressurization tests; 23.1441, Oxygen 
equipment and supply, paragraphs (c), (d) and (e); 23.1443, minimum 
mass flow of supplemental oxygen, paragraphs (a), (b), and (c); 
23.1445; Oxygen distribution system; 23.1447, Equipment standards for 
oxygen dispensing units, paragraphs (a) through (d) and (f); 23.1449, 
means of determining use of oxygen; and 23.1461, Equipment containing 
high energy rotors. Current part 23 regulations contain prescriptive 
language and means of compliance for the occupant physical environment 
requirements. The FAA proposes to remove the specific requirements to 
allow an applicant to specify the means of compliance for the physical 
needs of the occupants including temperature, ventilation, 
pressurization, supplemental oxygen, etc. For example, current Sec.  
23.831(a) requires carbon monoxide not exceeding one part in 20,000 
parts of air. The FAA proposes revising this by requiring breathable 
atmosphere without hazardous concentrations of gases and vapors.
vi. Proposed Sec.  23.800, Fire Protection Outside Designated Fire 
Zones
    Proposed Sec.  23.800 would require that insulation on electrical 
wire and electrical cable outside designated fire zones be self-
extinguishing. Proposed Sec.  23.800 would require airplane cockpit and 
cabin materials in certification levels 1, 2, and 3 be flame-resistant. 
Proposed Sec.  23.800 would require airplane cockpit and cabin 
materials in certification level 4 airplanes be self-extinguishing. 
Proposed Sec.  23.800 would also require that airplane materials in the 
baggage and cargo compartments, which are inaccessible in flight and 
outside designated fire zones, be self-extinguishing. Proposed Sec.  
23.800 would require that any electrical cable installation that would 
overheat in the event of circuit overload or fault be flame resistant. 
Additionally, proposed Sec.  23.800 would preclude thermal acoustic 
materials outside designated fire zones from being a flame propagation 
hazard. Proposed Sec.  23.800 would also require sources of heat that 
are capable of igniting adjacent objects outside designated fire zones 
to be shielded and insulated to prevent such ignition.
    Proposed Sec.  23.800 would require airplane baggage and cargo 
compartments, outside designated fire zones, to be located where a fire 
would be visible to the pilots, or equipped with a fire detection 
system and warning system, and be accessible for the manual 
extinguishing of a fire, have a built-in fire extinguishing system, or 
be constructed and sealed to contain any fire within the compartment.
    Proposed Sec.  23.800 would require a means to extinguish any fire 
in the cabin, outside designated fire zones, such that the pilot, while 
seated, could easily access the fire extinguishing means, and for 
certification levels 3 and 4 airplanes, passengers would have a fire 
extinguishing means available within the passenger compartment. Where 
flammable fluids or vapors might escape by leakage of a fluid system, 
proposed Sec.  23.800 would require each area, outside designated fire 
zones, be defined and have a means to make fluid and vapor ignition, 
and the resultant hazard, if ignition occurs, improbable. Additionally, 
proposed Sec.  23.800 would also require combustion heater 
installations outside designated fire zones be protected from 
uncontained fire.
    Proposed Sec.  23.800 would capture the safety intent of current 
Sec. Sec.  23.851, Fire extinguishers, paragraphs (a) and (b); 23.853, 
Passenger and crew compartment interiors, Paragraphs (a), (d)(3)(i), 
(d)(3)(iii) and (d)(3)(iv), (e), and (f); 23.855, Cargo and baggage 
compartment fire protection; 23.856, Thermal/acoustic insulation 
materials; 23.859, Combustion heater fire protection, paragraph (a); 
23.863, Flammable fluid fire protection, paragraphs (a) and (d); 
23.1359, Electrical system fire protection, paragraph (c); 23.1365, 
Electric cables and equipment, paragraph (b); 23.1383, Taxi and landing 
lights, paragraph (d); 23.1385, Position light system installation, 
paragraph (d). It would also capture the safety intent of CS-VLA-853, 
Compartment interiors. Proposed Sec.  23.800 would incorporate the 
requirements for flammability of all subpart D and F systems and 
equipment outside designated fire zones needed for continued safe 
flight and landing and remove specified design solutions and means of 
compliances.
vii. Proposed Sec.  23.805, Fire Protection in Designated Fire Zones
    Proposed Sec.  23.805 would require flight controls, engine mounts, 
and other flight structures within or adjacent to designated fire zones 
be capable of withstanding the effects of a fire. Proposed Sec.  23.805 
would require engines inside designated fire zones to remain attached 
to the airplane in the event of a fire or electrical arcing. Proposed 
Sec.  23.805 would also require terminals, equipment, and electrical 
cables, inside designated fire zones, used during emergency procedures, 
be fire-resistant.
    Proposed Sec.  23.805 would capture the safety intent of current 
Sec.  23.865, Fire protection of flight controls, engine mounts, and 
other flight structure and Sec.  23.1359(b), Electrical system fire 
protection. The intent of proposed Sec.  23.805 is to protect flight 
controls, engine mounts, and other flight structure as well as 
electrical cables,

[[Page 13483]]

terminals and equipment from the effects of fire in designated fire 
zones.
viii. Proposed Sec.  23.810, Lightning Protection of Structure
    Proposed Sec.  23.810 would preclude primary structure failure 
caused by exposure to the direct effects of lightning, that could 
prevent continued safe flight and landing for airplanes approved for 
IFR. Proposed Sec.  23.810 would require airplanes approved only for 
VFR to achieve lightning protection by following FAA accepted design 
practices found in FAA issued advisory circulars and in FAA accepted 
consensus standards.
    Proposed Sec.  23.810 would capture the safety intent of the 
current Sec.  23.867(a) and (c), Electrical bonding and protection 
against lightning and static electricity. The FAA proposes adopting the 
structure requirements in part 23, amendment 23-7 (34 FR 13078, August 
13, 1969), to limit the rule to protection of primary structure from 
direct effects of lightning.
ix. Reorganization of Subpart D
    The FAA proposes relocating the underlying safety. intent of 
various subpart D sections with proposed sections in subparts B, C, F, 
and G. The following table shows where the FAA proposes moving the 
current subpart D sections in part 23.

----------------------------------------------------------------------------------------------------------------
           Current section                      Title               Proposed section          Proposed title
----------------------------------------------------------------------------------------------------------------
23.601...............................  General................  23.500.................  Structural design.
23.603...............................  Materials and            23.500.................  Structural design.
                                        workmanship.
23.605...............................  Fabrication methods....  23.510.................  Materials and
                                                                                          processes.
23.607...............................  Fasteners..............  23.505.................  Protection of
                                                                                          structure.
23.609...............................  Protection of Structure  23.505.................  Protection of
                                                                                          structure.
23.611...............................  Accessibility..........  23.505.................  Protection of
                                                                                          structure.
23.613...............................  Material strength        23.510.................  Materials and
                                        properties and design                             processes.
                                        values.
23.619...............................  Special factors........  23.515.................  Special factors of
                                                                                          safety.
23.621...............................  Casting factors........  23.515.................  Special factors of
                                                                                          safety.
23.623...............................  Bearing factors........  23.515.................  Special factors of
                                                                                          safety.
23.625...............................  Fitting factors........  23.515.................  Special factors of
                                                                                          safety.
23.627...............................  Fatigue strength.......  23.405.................  Structural durability.
23.629...............................  Flutter................  23.410.................  Aeroelasticity.
23.641...............................  Proof of strength......  Means of Compliance....
23.651...............................  Proof of strength......  Means of Compliance....
23.655...............................  Installation...........  Means of Compliance....
23.657...............................  Hinges.................  23.515.................  Special factors of
                                                                                          safety.
23.659...............................  Mass balance...........  23.315.................  Flight load conditions.
23.671...............................  Control Surfaces--
                                        General.
(a)..................................  .......................  23.500.................  Structural design.
(b)..................................  .......................  23.1305................  Function and
                                                                                          installation.
23.672...............................  Stability augmentation   23.1305................  Function and
                                        and automatic and                                 installation.
                                        power-operated systems.
23.673...............................  Primary flight controls  23.1305................  Function and
                                                                                          installation.
23.675...............................  Stops..................  23.1305................  Function and
                                                                                          installation.
23.677...............................  Trim systems...........
(a)..................................  .......................  23.700.................  Flight control systems.
(b)..................................  .......................  23.700.................  Flight control systems.
(c)..................................  .......................  23.410.................  Aeroelasticity.
(d)..................................  .......................  23.700.................  Flight control systems.
23.679...............................  Control system locks...  23.1305................  Function and
                                                                                          installation.
23.681(a)............................  Limit load static tests  23.325(b)..............  Component loading
                                                                                          conditions.
23.681(b)............................  Limit load static tests  23.515.................  Special factors of
                                                                                          safety.
23.683...............................  Operation tests........  23.500(d)..............  Structural design.
23.685(a), (b), (c)..................  Control system details.  23.500(d)..............  Structural design.
23.685(d)............................  Control system details.  23.1305................  Function and
                                                                                          installation.
23.687...............................  Spring devices.........  23.410 and 23.500......  Aeroelasticity and
                                                                                          Structural design.
23.689...............................  Cable systems..........  .......................  Component loading
                                                                                          conditions, Structural
                                                                                          design, and Equipment
                                                                                          Systems and
                                                                                          Installations.
(a)..................................  .......................  23.700.................  Flight control systems.
(b)..................................  .......................  23.325(b), 23.500(d)...  Component loading
                                                                                          conditions, Structural
                                                                                          design.
(c)..................................  .......................  23.325(b), 23.500(d)...  Component loading
                                                                                          conditions, Structural
                                                                                          design.
(d)..................................  .......................  23.325(b), 23.500(d)...  Component loading
                                                                                          conditions, Structural
                                                                                          design.
(e)..................................  .......................  23.325(b), 23.500(d)...  Component loading
                                                                                          conditions, Structural
                                                                                          design.
(f)..................................  .......................  23.700.................  Flight control systems.
23.691...............................  Artificial stall
                                        barrier system.
(a)..................................  .......................  23.700.................  Flight control systems.
(b)..................................  .......................  23.700.................  Flight control systems.
(c)..................................  .......................  23.1305................  Function and
                                                                                          installation.
(d)..................................  .......................  23.700.................  Flight control systems.
(e)..................................  .......................  23.700.................  Flight control systems.
(f)..................................  .......................  23.700.................  Flight control systems.
(g)..................................  .......................  23.1315................  Equipment, systems and
                                                                                          Installations.
23.693...............................  Joints.................  23.515.................  Special factors of
                                                                                          safety.

[[Page 13484]]

 
23.697...............................  Wing flap controls.....
(a)..................................  .......................  23.700.................  Flight control systems.
(b) and (c)..........................  .......................  23.200.................  Controllability.
23.699...............................  Wing flap position       23.1500................  Flightcrew interface.
                                        indicator.
23.701...............................  Flap interconnection...  Means of Compliance....
23.703...............................  Takeoff warning system.
(a)..................................  .......................  23.700.................  Flight control systems.
(b)..................................  .......................  23.700.................  Flight control systems.
(c)..................................  .......................  Definition.............
23.721...............................  General................  23.910.................  Powerplant installation
                                                                                          hazard assessment.
23.723...............................  Shock absorption tests.  Means of Compliance....
23.725...............................  Limit drop tests.......  Means of Compliance....
23.726...............................  Ground load dynamic      Means of Compliance....
                                        tests.
23.727...............................  Reserve energy           Means of Compliance....
                                        absorption drop tests.
23.729...............................  Landing gear extension
                                        and retraction system.
(a)..................................  .......................  23.705.................  Landing gear systems.
(b)..................................  .......................  23.705.................  Landing gear systems.
(c)..................................  .......................  23.705.................  Landing gear systems.
(d)..................................  .......................  Means of Compliance....
(e)..................................  .......................  23.705.................  Landing gear systems.
(f)..................................  .......................  23.1315................  Equipment, systems and
                                                                                          installation.
(g)..................................  .......................  Means of Compliance....
23.731...............................  Wheels.................  23.705.................  Landing gear systems.
23.733...............................  Tires..................
(a)..................................  .......................  23.705.................  Landing gear systems.
(b)..................................  .......................  Means of Compliance....
(c)..................................  .......................  Means of Compliance....
23.735...............................  Brakes.................  23.705.................
(a)..................................  .......................  23.705.................  Landing gear systems.
(1)..................................  .......................  Means of Compliance....
(2)..................................  .......................  Means of Compliance....
(b)..................................  .......................  23.705.................  Landing gear systems.
(c)..................................  .......................  Means of Compliance....
(d)..................................  .......................  23.1315................  Equipment, systems and
                                                                                          installation.
(e)..................................  .......................  23.705.................  Landing gear systems.
(1)..................................  .......................  Means of Compliance....
(2)..................................  .......................  Means of Compliance....
23.737...............................  Skis...................  23.705.................  Landing gear systems.
23.745...............................  Nose/Tail wheel          23.1500................  Flightcrew interface.
                                        steering.
23.751...............................  Main float buoyancy....
(a)..................................  .......................  710....................  Buoyancy for seaplanes
                                                                                          and amphibians.
(b)..................................  .......................  Means of Compliance....
23.753...............................  Main float design......  23.320.................  Ground and water load
                                                                                          conditions.
23.755...............................  Hulls..................  23.710.................  Buoyancy for seaplanes
                                                                                          and amphibians.
23.757...............................  Auxiliary floats.......  23.710.................  Buoyancy for seaplanes
                                                                                          and amphibians.
23.771...............................  Pilot compartment......
(a)..................................  .......................  23.1500................  Flightcrew interface.
(b)..................................  .......................  23.755.................  Occupant physical
                                                                                          environment.
(c ).................................  .......................  23.755.................  Occupant physical
                                                                                          environment.
23.773...............................  Pilot compartment view.
(a)..................................  .......................  23.1500................  Flightcrew interface.
(b)..................................  .......................  23.755.................  Occupant physical
                                                                                          environment.
23.775...............................  Windshields and windows
(a), (b), (c), (d)...................  .......................  23.755.................  Occupant physical
                                                                                          environment.
(e)..................................  .......................  Means of Compliance....
(f)..................................  .......................  23.1405................  Flight in icing
                                                                                          conditions.
(g)..................................  .......................  Means of Compliance....
(h)..................................  .......................  23.755.................  Occupant physical
                                                                                          environment.
23.777...............................  Cockpit controls.......  23.1500................  Flightcrew interface.
23.779...............................  Motion and effect of     23.1500................  Flightcrew interface.
                                        cockpit controls.
23.781...............................  Cockpit control knob     23.1500................  Flightcrew interface.
                                        shape.
23.783...............................  Doors..................
(a), (b), (c), (d)...................  .......................  23.750.................  Means of egress and
                                                                                          emergency exits.
(e), (f), (g)........................  .......................  Means of Compliance....
23.785...............................  Seats, berths, litters,  23.600 and 23.515......  Special factors of
                                        safety belts, and                                 safety, Emergency
                                        shoulder harnesses.                               landing conditions.
23.787...............................  Baggage and cargo        23.600(e)..............  Emergency landing
                                        compartments.                                     conditions.
23.791...............................  Passenger information    23.755.................  Occupant physical
                                        signs.                                            environment.
23.803...............................  Emergency evacuation...

[[Page 13485]]

 
(a)..................................  .......................  23.750.................  Means of egress and
                                                                                          emergency exits.
(b)..................................  .......................  Means of Compliance....
23.805...............................  Flightcrew emergency     23.750.................  Means of egress and
                                        exits.                                            emergency exits.
23.807...............................  Emergency exits........
(a)(3 ), (b)(1), (c), (d)(1), (d)(4).  .......................  Means of Compliance....
Balance of 23.807....................  .......................  23.750.................  Means of egress and
                                                                                          emergency exits.
23.811...............................  Emergency exit marking.  23.750.................  Means of egress and
                                                                                          emergency exits.
23.812...............................  Emergency lighting.....  23.750.................  Means of egress and
                                                                                          emergency exits.
23.813...............................  Emergency exit access..
(a)..................................  .......................  23.750.................  Means of egress and
                                                                                          emergency exits.
(b)..................................  .......................  Means of Compliance....
CS-VLA 853...........................  .......................  23.750.................  Means of egress and
                                                                                          emergency exits.
23.815...............................  Width of aisle.........  23.750.................  Means of egress and
                                                                                          emergency exits.
23.831...............................  Ventilation............  23.755.................  Occupant physical
                                                                                          environment.
23.841(a), (b)(6), (c), (d)..........  Pressurized cabins.....  23.755.................  Occupant physical
                                                                                          environment.
(b)(1) through (5) and (7)...........  .......................  Means of Compliance....
23.843...............................  Pressurization tests...  23.755.................  Occupant physical
                                                                                          environment.
23.851...............................  Fire extinguishers.....
(a) and (b)..........................  .......................  23.800.................  Fire protection outside
                                                                                          designated fire zones.
(c)..................................  .......................  Means of Compliance....
23.853...............................  Passenger and crew
                                        compartment interiors.
(a)..................................  .......................  23.800.................  Fire protection outside
                                                                                          designated fire zones.
(b)(c) and (d)(1)(2).................  .......................  Means of Compliance....
(d)(3)(i), (d)(3)(iii), (d)(3)(iv)...  .......................  23.800.................  Fire protection outside
                                                                                          designated fire zones.
(e)..................................  .......................  23.800.................  Fire protection outside
                                                                                          designated fire zones.
(f)..................................  .......................  23.800.................  Fire protection outside
                                                                                          designated fire zones.
23.855...............................  Cargo and baggage        23.800.................  Fire protection outside
                                        compartment fire                                  designated fire zones.
                                        protection.
23.856...............................  Thermal/acoustic         23.800.................  Fire protection outside
                                        insulation materials.                             designated fire zones.
23.859...............................  Combustion heater fire
                                        protection.
(a)..................................  .......................  23.800.................  Fire protection outside
                                                                                          designated fire zones.
(b) thru (i).........................  .......................  Means of Compliance....
23.863...............................  Flammable fluid fire
                                        protection.
(a) and (d)..........................  .......................  23.800.................  Fire protection outside
                                                                                          designated fire zones.
(b) and (c)..........................  .......................  Means of Compliance....  Fire protection outside
                                                                                          designated fire zones.
23.865...............................  Fire protection of       23.805.................  Fire protection in
                                        flight controls,                                  designated fire zones.
                                        engine mounts, and
                                        other flight structure.
23.867...............................  Electrical bonding and
                                        protection against
                                        lightning and static
                                        electricity.
(a), (c).............................  .......................  23.810.................  Lightning protection of
                                                                                          structure.
(b)..................................  .......................  23.1320................  Electrical and
                                                                                          electronic system
                                                                                          lightning protection.
23.871...............................  Leveling means.........  Means of Compliance....
----------------------------------------------------------------------------------------------------------------

5. Subpart E--Powerplant
a. General Discussion
    The FAA proposes substantial changes to subpart E based on two 
considerations. First, many of the current regulations could be 
combined to provide fewer regulations that accomplish the same safety 
intent. Second, part 23 overlaps with the requirements in parts 33 and 
35. Refer to appendix 1 of this preamble for a cross-reference table 
detailing how the current regulations are addressed in the proposed 
part 23 regulations.
b. Specific Discussion of Changes
i. Proposed Sec.  23.900, Powerplant Installation
    Proposed Sec.  23.900 would clarify, for the purpose of this 
subpart, that the airplane powerplant installation must include each 
component necessary for propulsion, affects propulsion safety, or 
provides auxiliary power to the airplane. Proposed Sec.  23.900 would 
require the applicant to construct and arrange each powerplant 
installation to account for likely hazards in operation and maintenance 
and, except for simple airplanes,\24\ each aircraft engine would have 
to be type certificated.
---------------------------------------------------------------------------

    \24\ Refer to Section III, Discussion of Proposal, paragraphs A 
and B of this NPRM for definition and discussion of a simple 
airplane.
---------------------------------------------------------------------------

    Proposed Sec.  23.900 would capture the safety intent of current 
Sec. Sec.  23.901, Installation, paragraphs (a), (b), and (f); 23.903, 
Engines, paragraph (a); 23.905, Propellers, paragraph (a), 23.909, 
Turbocharger systems, paragraphs (a) and (c); and 23.925, Propeller 
clearance. Proposed Sec.  23.900 would combine the installation 
requirements that are scattered throughout the subpart into a

[[Page 13486]]

general requirement for installation, and remove any duplication with 
part 33. The following table illustrates the duplication between the 
current part 23 regulations and part 33 requirements:

------------------------------------------------------------------------
                Part 23                              Part 33
------------------------------------------------------------------------
Sec.   23.901(d), Installation.........  Sec.   33.33, Vibration.
Sec.   23.901(e), Installation.........  Sec.   33.1, Applicability.
Sec.   23.934, Turbojet and turbofan     Sec.   33.97, Thrust reversers.
 engine thrust reverser systems tests.
Sec.   23.939, Powerplant operating      Sec.  Sec.   33.61 thru 33.79.
 characteristics.
Sec.   23.1011, Oil System--General....  Sec.  Sec.   33.39 and 33.71,
                                          Lubrication system.
Sec.   23.1013(a) and (d), Oil tanks...  Sec.  Sec.   33.39, and 33.71,
                                          Lubrication system.
Sec.   23.1015, Oil tank tests.........  Sec.   33.33, Vibration.
Sec.   23.1023, Oil radiators..........  Sec.   33.33, Vibration.
Sec.   23.1041, Cooling--General.......  Sec.   33.1, Applicability.
Sec.   23.1043, Cooling tests..........  Sec.  Sec.   33.41 and 33.81,
                                          Applicability--Block Tests.
Sec.   23.1045, Cooling test procedures  Sec.   33.81, Applicability--
 for turbine engine powered airplanes.    Block Tests.
Sec.   23.1047, Cooling test procedures  Sec.   33.35, Fuel and
 for reciprocating engine powered         induction system.
 airplanes.
Sec.   23.1061, Liquid Cooling--         Sec.   33.21, Engine cooling.
 Installation.
Sec.   23.1063, Coolant tank tests.....  Sec.   33.41 and 33.81,
                                          Applicability--Block Tests.
Sec.   23.1093, Induction system icing   Sec.  Sec.   33.35(b), Fuel and
 protection.                              induction system and 33.68,
                                          Induction system icing.
Sec.   23.1099, Carburetor deicing       Sec.   33.35, Fuel and
 fluid system detail design.              induction system.
------------------------------------------------------------------------

    Additionally, proposed Sec.  23.900 would identify the scope of the 
powerplant installation in the same manner as the current requirements. 
However, the FAA would redefine several terms to allow for alternate 
sources of propulsion, such as electric motors. The FAA considers the 
term powerplant to include all equipment used by the airplane that 
provides propulsion or auxiliary power. The word engine would be 
replaced with the term power unit and would include other power sources 
driven by fuel such as liquid fuel, electrical, or other power sources 
not yet envisioned. This proposal also predicates that each airplane 
power unit or propeller receive a type certificate as a prerequisite 
for installation, with the exception of simple airplanes. The current 
part 33 airworthiness standards did not envision providing 
certification requirements for types of engines outside of those that 
operate on fossil fuels. As such, the ability of an applicant to obtain 
the required engine type certificate for an alternate fuel type may be 
impractical. For those power units, the FAA proposes to include them in 
the airplane certification, which could include the use of an ELOS to 
part 23. The FAA would expect an applicant to utilize all the 
requirements listed in part 33 as a baseline matrix to find compliance 
for an alternate powerplant type and for those requirements that could 
not be met. Also, Sec.  21.16, Special conditions, may apply. It should 
be noted that additional requirements might also be necessary due to an 
absence of a corresponding part 33 requirement. This matrix would 
become part of the certification baseline and recorded in an issue 
paper as an ELOS, exemption, or special condition. Also, simple 
airplanes will follow the precedence set for CS-VLA and will maintain 
the exception to the requirement to be type certificated.
ii. Proposed Sec.  23.905, Propeller Installation
    Proposed Sec.  23.905 would retain the requirement that each 
propeller be type certificated, except for simple airplanes. Proposed 
Sec.  23.905 would retain the requirement that each pusher propeller be 
marked so that it is conspicuous under daylight conditions. All the 
other requirements of the current section either duplicate part 35 
standards, or would condense into the other requirements proposed in 
Sec. Sec.  23.900, Powerplant installation; 23.910, Powerplant 
installation hazard assessment; and 23.940, Powerplant ice protection.
iii. Proposed Sec.  23.910, Powerplant Installation Hazard Assessment
    Proposed Sec.  23.910 would require an applicant to assess each 
powerplant separately and in relation to other airplane systems and 
installations to show that a failure of any powerplant system component 
or accessory will not--
     Prevent continued safe flight and landing;
     Cause serious injury; and
     Require immediate action by crewmembers for continued 
operation of any remaining powerplant system.
    Proposed Sec.  23.910 would capture the safety intent of current 
Sec. Sec.  23.721, Landing gear--General; 23.903, Engines, paragraph 
(c); 23.905, Propellers, paragraph (h); 23.909, Turbocharger systems, 
paragraph (b), (c), and (e); 23.933 Reversing systems, paragraph (b); 
23.937, Turbopropeller-drag limiting systems, paragraph (a); 23.959, 
Unusable fuel supply; 23.979, Pressure fueling systems, paragraphs (c) 
and (d); 23.991, Fuel pumps, paragraph (d); 23.994, Fuel system 
components; 23.1001, Fuel jettisoning system, paragraph (h); 23.1027, 
Propeller feathering system; 23.1111, Turbine engine, paragraph (a) and 
(c); 23.1123, Exhaust system; 23.1125 Exhaust heat exchangers, 
paragraph (a); 23.1142, Auxiliary power unit controls, paragraphs (d) 
and (e); 23.1155, Turbine engine reverse thrust and propeller pitch 
settings below the flight regime; 23.1163, Powerplant accessories, 
paragraphs (b) and (d); 23.1191, Firewalls, paragraph (f); 23.1193, 
Cowling and nacelle, paragraphs (f) and (g); 23.1201, Fire 
extinguishing systems materials, paragraph (a); and 23.1203, Fire 
detector system, paragraphs (b) and (c).
    The proposed standard would reduce the repetitive requirements 
found throughout the subpart and create one general powerplant 
requirement to analyze and mitigate hazards associated with the 
powerplant installation. For example, current Sec.  23.903(b)(1) 
requires that design precautions be taken to minimize the hazards to 
the airplane in the event of an engine rotor failure or a fire 
originating inside the engine that could burn though the engine case. 
These are very specific failure conditions, but are actually only two 
small categories of many engine failure

[[Page 13487]]

conditions an applicant must assess. Section 23.903(c) requires that 
multiple engines must be isolated from one another so a malfunction of 
one engine does not affect the operation of the other. This is a 
general analysis technique frequently called common mode analysis that 
should apply to all powerplant components and include other critical 
airplane systems that are not powerplant related, but could be affected 
by a powerplant failure. Hazards the FAA proposes to remove from other 
regulations and which would be addressed in this proposed section 
include, but are not limited to, fire, ice, rain and bird ingestion, 
rotorburst, engine case burn through, and flammable leakage.
iv. Proposed Sec.  23.915, Automatic Power Control Systems
    Proposed Sec.  23.915 would require a power or thrust augmentation 
system that automatically controls the power or thrust on the operating 
powerplant to provide an indication to the flightcrew when the system 
is operating; provide a means for the pilot to deactivate the automatic 
functions; and prevent inadvertent deactivation.
    Proposed Sec.  23.915 would capture the safety intent of current 
Sec.  23.904, Automatic power reserve system and appendix H to part 
23--Installation of An Automatic Power Reserve (APR) System. To foster 
the growth and approval of technological advances, the FAA believes 
that the detailed and prescriptive language of appendix H is more 
appropriate as means of compliance. We would also include requirements 
for thrust augmenting systems into this proposed section since there 
seems to be a trend in general aviation to provide thrust management 
systems more sophisticated than historical automatic power reserve 
systems.
v. Proposed Sec.  23.920, Reversing Systems
    Proposed Sec.  23.920 would require an airplane to be capable of 
continued safe flight and landing under any available reversing system 
setting, and would capture the safety intent of current Sec.  23.933(a) 
and (b). The current rule includes a separate requirement for a 
propeller reversing system that would be covered in the more general 
language of the proposed section and applied to any type of reverser 
system. Current Sec.  23.933 also requires an analysis of the system 
for a failure condition. Those provisions would be addressed in the 
general analysis requirements of proposed Sec.  23.910.
vi. Proposed Sec.  23.925, Powerplant Operational Characteristics
    Proposed Sec.  23.925 would require the powerplant to operate at 
any negative acceleration that could occur during normal and emergency 
operation within the airplane operating limitations. Proposed Sec.  
23.925 would require the pilot to have the capability to stop and 
restart the powerplant in flight. Proposed Sec.  23.925 would require 
the airplane to have an independent power source for restarting each 
powerplant following an in-flight shutdown.
    Proposed Sec.  23.925 would capture the safety intent of current 
Sec. Sec.  23.903, Engines, paragraph (d), (e), (f), and (g); 23.939, 
Powerplant operating characteristics; and 23.943, Negative 
acceleration. Current Sec.  23.939 addresses powerplant operating 
characteristics and clearly requires an analysis that would be required 
by proposed Sec.  23.910 and the existing requirements of part 33. 
Current Sec.  23.943 would be included in this proposed rule because it 
is another analysis requirement, and one that provides an environment 
where powerplant systems are required to operate.
vii. Proposed Sec.  23.930, Fuel Systems
    Proposed Sec.  23.930 would require that each fuel system provide 
an independent fuel supply to each powerplant in at least one 
configuration and prevent ignition from an unknown source. This section 
would require that each fuel system provide the fuel required to 
achieve maximum power or thrust plus a margin for likely variables in 
all temperature conditions within the operating envelope of the 
airplane and provide a means to remove the fuel from the airplane. 
Proposed Sec.  23.930 would require each fuel system to be capable of 
retaining fuel when subject to inertia loads under expected operating 
conditions and prevent hazardous contamination of the fuel supply.
    Proposed Sec.  23.930 would require each fuel storage system to 
withstand the loads and pressures under expected operating conditions 
and provide a means to prevent loss of fuel during any maneuver under 
operating conditions for which certification is requested. Also, 
proposed Sec.  23.930 would require each fuel storage system to prevent 
discharge when transferring fuel, provide fuel for at least one-half 
hour of operation at maximum continuous power or thrust, and be capable 
of jettisoning fuel, if required for landing.
    Proposed Sec.  23.930 would require installed pressure refueling 
systems to have a means to prevent the escape of hazardous quantities 
of fuel, automatically shut-off before exceeding the maximum fuel 
quantity of the airplane, and provide an indication of a failure at the 
fueling station. Proposed Sec.  23.930 would capture the safety intent 
of current Sec. Sec.  23.951, Fuel System--General, paragraphs (a), 
(b), (c), and (d); 23.953, Fuel System; 23.954, Fuel system lightning 
protection; 23.955, Fuel flow; 23.957, Flow between interconnected 
tanks, paragraph (a); 23.961, Fuel system hot weather operation; 
23.963, Fuel tanks: General, paragraphs (a), (d), and (e); 23.977, Fuel 
tank outlet; 23.979, Pressure fueling systems, paragraphs (a) and (b); 
23.991, Fuel pumps, paragraphs (a), (b), and (c); 23.997, Fuel strainer 
or filter, paragraphs (a), (b), (c), and (d); 23.999, Fuel system 
drains; and 23.1001, Fuel jettisoning system, paragraph (a).
    The FAA believes that the regulations for the design of fuel 
systems may be overly prescriptive and exceed what is necessary to 
design a safe system. Accordingly, a more general set of requirements 
could include the intent of many current rules. More importantly, this 
proposed rule would allow for other types of energy sources to power 
propulsion systems such as electrical motors and future energy sources.
viii. Proposed Sec.  23.935, Powerplant Induction and Exhaust Systems
    Proposed Sec.  23.935 would require the air induction system to 
supply the air required for each power unit and its accessories under 
expected operating conditions, and provide a means to discharge 
potential harmful material. Proposed Sec.  23.935 would capture the 
safety intent of current Sec. Sec.  23.1091, Air induction system, 
paragraph (a); 23.1101, Induction air preheater design, paragraph (a); 
23.1103, Induction system ducts; 23.1107, Induction system filters; and 
23.1121, Exhaust System--General, paragraphs (a) through (g). This 
proposed rule would combine induction and exhaust systems into a single 
rule because of the commonality with issues associated with moving air. 
The prescriptive language of the regulations identified above in this 
paragraph drove the development of this proposed section. For example, 
Sec.  23.1091(b) mandates a certain number of intake sources and 
specifies particular requirements for a primary and alternate intakes. 
Current Sec.  23.1101 requires inspection access of critical parts, and 
current Sec.  23.1103 is considered a part of a proper safety analysis 
that would be required by proposed Sec.  23.910.

[[Page 13488]]

ix. Proposed Sec.  23.940, Powerplant Ice Protection
    Proposed Sec.  23.940 would require the airplane design, including 
the engine induction system, to prevent foreseeable accumulation of ice 
or snow that would adversely affect powerplant operation. Proposed 
Sec.  23.940 would also require the applicant design the powerplant to 
prevent any accumulation of ice or snow that would adversely affect 
powerplant operation, in those icing conditions for which certification 
is requested. Proposed Sec.  23.940 would capture the safety intent of 
current Sec. Sec.  23.905, Propellers, paragraph (e); 23.929, Engine 
installation ice protection; 23.975, Fuel tank vents and carburetor 
vapor vents, paragraph (a)(1); 23.1093, Induction system icing 
protection; 23.1095, Carburetor deicing fluid flow rate; 23.1097, 
Carburetor deicing fluid system capacity; and 23.1099, Carburetor 
deicing fluid system detail design.
    Proposed Sec.  23.940(a) would reflect the requirements in current 
Sec.  23.1093, which applies to all airplanes, regardless if flight in 
icing certification is sought. We are proposing to remove the type of 
powerplant to accommodate for new powerplant technologies. In addition, 
we propose to define other foreseeable icing in the means of 
compliance, which would include conditions conducive to induction icing 
of reciprocating engines. Foreseeable icing in the means of compliance 
would also include the cloud icing conditions of appendix C to part 25, 
currently defined in Sec.  23.1093(b)(1)(i), falling and blowing snow 
currently defined in Sec.  23.1093(b)(1)(ii), and ground ice fog 
conditions currently defined in Sec.  23.1093(b)(2). The FAA proposes 
to remove the prescriptive requirements of the current Sec. Sec.  
23.1093(a), 23.1095, 23.1097, and 23.1099 as these are more 
appropriately considered as means of compliance. The FAA would expect 
the means of compliance to expand the ground ice fog conditions to 
colder ambient temperatures to harmonize with EASA. The FAA would also 
expect the means of compliance to include optional ground and flight 
freezing drizzle and freezing rain conditions, similar to appendix O of 
part 25, for those airplanes that seek certification to operate in 
those conditions. The Part 23 Icing ARC had recommended specific pass/
fail criteria for the effect of ice accretion on engine operation. The 
FAA would expect this criterion to be defined in a means of compliance. 
Proposed paragraph (a) would require an airplane design to prevent 
``foreseeable'' ice or snow accumulation, including accumulation in 
inadvertent icing encounters, described in appendix C to part 25, on 
airplanes not certified for icing, which may pose a shed hazard to the 
powerplant.
    Airplane design in proposed Sec.  23.940(a) refers to the engine 
induction system and airframe components on which accumulated ice may 
shed into the powerplant. Powerplant design in proposed Sec.  23.940(b) 
refers to the engine, propeller, and other powerplant components such 
as cooling inlets.
    Proposed Sec.  23.940(b) would apply only to airplanes certified 
for flight in icing and would require compliance to the icing 
requirements in part 33, which currently only apply to turbine engines. 
Part 33, amendment 33-34 (79 FR 65507, November 4, 2014) and effective 
January 5, 2015, added SLD and ice crystal requirements to Sec.  33.68 
and amended the engine ice ingestion requirements in Sec.  33.77. 
Proposed Sec.  23.940(b) would require installation of an engine(s) 
certified to Sec.  33.68 amendment 33-34, or later, if the airplane 
will be certified for flight in freezing drizzle and freezing rain. 
Proposed Sec.  23.940(b) would allow an airplane manufacturer to 
install an engine, type certified at an earlier amendment, in an 
airplane not certified for flight in freezing drizzle or freezing rain, 
as long as no ADs have been applied that relate to engine operation in 
inadvertent SLD or ice crystal conditions. Airplanes certified under 
part 23 have not had ADs related to SLD or ice crystals. Certain part 
23 turbojet engines have experienced thrust rollback due to ice 
crystals blocking the heated inlet temperature probe. The FAA would 
expect the means of compliance to address this in a similar manner to 
what is accomplished on current certification projects. The engine ice 
ingestion requirements of the current Sec.  23.903(a)(2) would be moved 
to proposed Sec.  23.940(b).
x. Proposed Sec.  23.1000, Powerplant Fire Protection
    Proposed Sec.  23.1000 would require that a powerplant only be 
installed in a designated fire zone and would require an applicant to 
install a fire detection system in each designated fire zone for 
certification levels 3 and 4 airplanes. This rulemaking effort is 
maintaining the current level of safety for fire protection. While not 
a perfect one-to-one relationship, airplanes equivalent to 
certification levels 1 and 2 airplanes are not required to have a fire 
detection system today and therefore, should not be required to have 
them in this proposed rule. This would increase the cost of 
certification. Each fire detection system would be required to provide 
a means to alert the flightcrew in the event of a detection of fire or 
failure of the system and a means to check the fire detection system in 
flight. Proposed Sec.  23.1000 would also require an applicant to 
install a fire extinguishing system for certification levels 2, 3, and 
4 airplanes with a powerplant located outside the pilot's view that 
uses combustible fuel.
    Additionally, proposed Sec.  23.1000 would require each component, 
line, and fitting carrying flammable fluids, gases, or air subject to 
fire conditions to be fire resistant, except components storing 
concentrated flammable material would have to be fireproof or enclosed 
by a fireproof shield. Proposed Sec.  23.1000 would also require an 
applicant to provide a means to shut off fuel or flammable material for 
each powerplant, while not restricting fuel to remaining units, and 
prevent inadvertent operation. Proposed Sec.  23.1000 would capture the 
safety intent of current Sec. Sec.  23.1181, Designated fire zones: 
Regions included; 23.1182, Nacelle areas behind firewalls; 23.1183, 
Lines, fittings, and components; 23.1189, Shutoff means; 23.1191, 
Firewalls; 23.1192 Engine accessory compartment diaphragm; 23.1193, 
Cowling and nacelle; 23.1195, Fire extinguishing systems; 23.1197, Fire 
extinguishing agents; 23.1199, Extinguishing agent containers; 23.1201, 
Fire extinguishing system materials; and 23.1203, Fire detector system.
    Regulations for fuel may have become too detailed and prescriptive. 
A more general set of requirements should capture the intent of these 
many rules. More importantly, this new proposed rule would allow other 
types of energy sources to power propulsion systems such as electrical 
motors and future energy sources.
xi. Current Subpart E Regulations Relocated to Other Proposed Subparts
    The requirements of current Sec.  23.903(b)(1) would be moved to 
subpart C, Sec.  23.405, Structural durability, paragraph (d). Section 
23.903(b)(1) requires design precautions for turbine engine 
installations to be taken to minimize hazards to the airplane in the 
event of an engine rotor failure or of a fire originating inside the 
engine which burns through the engine case.
    Additionally, the requirements of current Sec.  23.929 would be 
moved to proposed Sec.  23.940(b) and would only apply to airplanes 
certified for flight in icing. The means of compliance for Sec.  
23.940(b) should address propeller ice

[[Page 13489]]

protection system design and analysis. However, the means of compliance 
for climb performance for proposed Sec.  23.230 should address ice 
accretion effects on propeller performance on airplanes certified for 
flight in icing.
xii. Removal of Subpart E Current Regulations
    The following current regulations are considered duplicative of 
part 35 and would be removed from subpart E: Sec.  23.905(b)--
duplicative of Sec.  35.5, Propeller ratings and operation limitations; 
Sec.  23.905(c)--duplicative of Sec.  35.22, Feathering propellers; 
Sec.  23.905(d)--duplicative of Sec. Sec.  35.21, 35.23, 35.42 and 
35.43; and Sec.  23.905(e)(g) and (h)--duplicative of Sec.  35.7, 
Features and characteristics.
6. Subpart F--Equipment
a. General Discussion
    The proposed changes to subpart F would consolidate the current 
rules into new performance-based standards and allow for use of new 
technologies once consensus standards are developed that could be used 
as a means of compliance.The FAA believes the proposed part 23 
requirements would maintain the current level of safety while staying 
relevant for new future technologies. The prescriptive design solutions 
in the current rules are often not relevant to new technology requiring 
special conditions, exemptions, and ELOS findings. The rate of new 
technology development and adoption has increased dramatically in the 
last decade. As a result, airplane systems with new features and 
capabilities are rapidly becoming available. The FAA believes that 
removing the prescriptive design solutions, which are based on outdated 
or existing technology, while focusing on the safety intent of the rule 
and maintaining design solutions as a documented means of compliance 
would enable the adoption of newer technologies.
    The FAA also believes the current part 23 regulatory prescriptive 
structure does not effectively address the safety continuum, 
particularly the low performance end of the continuum. Recent part 23 
amendments have increasingly focused on high-performance, complex 
airplanes. These stricter requirements have also been applied to the 
low-performance airplanes even though their risk in the safety 
continuum is lower. This has created an unintended barrier to new 
safety enhancing technology in low-performance airplanes.
b. Specific Discussion of Changes
i. Proposed Sec.  23.1300, Airplane Level Systems Requirements
    Proposed Sec.  23.1300 would require equipment and systems that are 
required for an airplane to operate safely, be designed and installed 
to meet the level of safety applicable to the certification and 
performance levels of the airplane, and to perform their intended 
function throughout the operating and environmental limits specified by 
an applicant. Proposed Sec.  23.1300 would mandate that 
non[hyphen]required airplane equipment and systems, considered 
separately and in relation to other systems, be designed and installed 
so their operation or failure would not have an adverse effect on the 
airplane or its occupants.
    Proposed Sec.  23.1300 would capture the safety intent found in 
portions of current Sec. Sec.  23.1301, Function and installation; 
23.1303, Flight and navigation instruments; 23.1305, Powerplant 
instruments; 23.1307, Miscellaneous equipment; 23.1309, Equipment, 
systems, and installations; 23.1311, Electronic display instrument 
systems; 23.1321, Arrangement and visibility; 23.1323, Airspeed 
indicating system, 23.1325, Static pressure system; 23.1327, Magnetic 
direction indicator; 23.1329, Automatic pilot system; 23.1335, Flight 
director systems; 23.1337, Powerplant instruments installation; 
23.1351, Electrical Systems and Equipment--General; 23.1353, Storage 
battery design and installation; and 23.1361, Master switch 
arrangement.
    The current requirements can be traced back to CAR 3, specifically 
CAR 3.651, 3.652, 3.655, 3.661, 3.662, 3.663, 3.665, 3.666, 3.667, 
3.669, 3.670, 3.671, 3.672, 3.673, 3.674, 3.681, 3.682, 3.686, 3.687, 
and 3.683. These requirements, including Sec.  23.1311, which does not 
have a corresponding rule in CAR 3, were based on the technology and 
design solutions available at the time of their adoption. Although 
these requirements are appropriate for traditional systems found in 
airplanes designed to these assumptions, they lack the flexibility to 
adopt current and anticipated technologies and design capabilities. The 
FAA wants to facilitate the use of systems in new airplanes that reduce 
pilot workload and enhance safety. The FAA proposes the use of 
performance-based language that maintains the level of safety achieved 
with the current requirements for traditionally designed airplanes but 
also allows for alternative system designs in the future.
    Proposed Sec.  23.1300(a) would address equipment and systems 
required to operate safely. Required equipment may be defined by other 
parts such as part 91 or part 135, by other sections of this part such 
as equipment necessary for flight into known icing, or other 
requirements placed on the Type Certificate Data Sheet (TCDS) such as a 
working autopilot for single pilot operations. The FAA proposes in 
Sec.  23.1300(b) that non-required equipment may be installed because 
it offers some benefit and its failure or use would not result in a 
reduction in safety of the airplane or for its occupants from the base 
aircraft if the system was not installed. This proposed section would 
contain general requirements for the environmental qualifications of 
installed equipment, and would require installed equipment to perform 
its intended function over its defined environmental range. This would 
mean that the equipment should have the same environmental 
qualification as requested for the useful range of the airplane.
    Proposed Sec.  23.1300(b) would not mandate that non-required 
equipment and systems function properly during all airplane operations 
once in service, provided all potential failure conditions do not 
effect safe operation of the airplane. The equipment or system would 
have to function in the manner expected by the manufacturer's operating 
manual for the equipment or system. An applicant's statement of 
intended function would have to be sufficiently specific and detailed 
so that the FAA could evaluate whether the system was appropriate for 
the intended function.
ii. Proposed Sec.  23.1305, Function and Installation
    Proposed Sec.  23.1305 would require that each item of installed 
equipment perform its intended function, be installed according to 
limitations specified for that equipment, and the equipment be labeled, 
if applicable, due to size, location, or lack of clarity as to its 
intended function, as to its identification, function or operating 
limitations, or any combination of these factors. Proposed Sec.  
23.1305 would require a discernable means of providing system operating 
parameters required to operate the airplane, including warnings, 
cautions, and normal indications to the responsible crewmember. 
Proposed Sec.  23.1305 would require information concerning an unsafe 
system operating condition be provided in a clear and timely manner to 
the crewmember responsible for taking corrective action.

[[Page 13490]]

    Proposed Sec.  23.1305 would capture the safety intent found in 
portions of the current Sec. Sec.  23.671, Control systems-General; 
23.672, Stability augmentation and automatic and power-operated 
systems; 23.673, Primary flight controls; 23.675, Stops; 23.679, 
Control system locks; 23.685(d), Control system details; 23.691(c), 
Artificial stall barrier system; 23.1361, Master switch arrangement; 
and 23.1365(a) and (b), Electric cables and equipment; 23.1301, 
Function and installation; 23.1303, Flight and navigation instruments; 
23.1305, Powerplant instruments; 23.1309, Equipment, systems, and 
installations; 23.1322, Warning, caution, and advisory lights; 23.1323, 
Airspeed indicating system; 23.1326, Pitot heat indication systems; 
23.1327, Magnetic direction indicator; 23.1329, Automatic pilot system; 
23.1331, Instruments using a power source; 23.1335, Flight director 
systems; 23.1337, Powerplant instruments installation; 23.1351, 
Electrical Systems and Equipment--General; 23.1353, Storage battery 
design and installation; 23.1365, Electric cables and equipment; 
23.1367, Switches; 23.1416, Pneumatic de-icer boot system. The current 
requirements can be traced to CAR 3, specifically, CAR 3.651, 3.652, 
3.655, 3.663, 3.666, 3.667, 3.668, 3.669, 3.670, 3.671, 3.672, 3.673, 
3.674, 3.675, 3.681, 3.682, 3.683, 3.686, 3.687, 3.693, 3.694, 3.696, 
3.697, 3.700, 3.712, and 3.726. These requirements, including 
Sec. Sec.  23.1322, 23.1326, and 23.1441, which did not have 
corresponding rules in CAR 3, were based on the technology and design 
solutions available at the time of their adoption. Although these 
requirements are appropriate for traditional systems and designs found 
in airplanes designed to these assumptions, they lack the flexibility 
to adopt current and anticipated technologies and design capabilities. 
The FAA wants to facilitate the use of systems in new airplanes that 
reduce pilot workload and enhance safety. The FAA proposes the use of 
performance-based language that maintains the safety requirements for 
traditionally designed airplanes, but also allows for alternative 
system designs.
    The equipment or system would have to function in the manner 
expected by the manufacturer's operating manual for the equipment or 
system. An applicant's statement of intended function would have to be 
sufficiently specific and detailed so that the FAA could evaluate 
whether the system was appropriate for the intended function. The 
equipment should function when installed as intended by the 
manufacturer's instructions. The intent is for an applicant to define 
proper functionality and to propose an acceptable means of compliance.
    Proposed Sec.  23.1305(a) would require that equipment be installed 
under prescribed limitations. Therefore, if an equipment manufacturer 
specified any allowable installation requirements, the installer would 
stay within the limitations or substantiate the new limits. The 
proposed requirement that the equipment be labeled as to its 
identification, function or operating limitations, or any combination 
of these factors, if applicable, would apply to the manufacturer of the 
equipment, not to the installer.
    Proposed Sec.  23.1305 would require that information concerning an 
unsafe system operating condition be provided to the flightcrew. 
Microprocessing units that monitor parameters and warn of system 
problems have already been incorporated in some airplanes and are used 
by other industries, including the automobile and nuclear energy 
fields. Pilots may not monitor gauges as they used to; instead, they 
could rely on warnings and alerts. The FAA does not propose to allow 
simple on-off failure lights to replace critical trend displays. 
Warning systems would need to be sophisticated enough to read 
transients and trends, when appropriate, and give useful warning to the 
flightcrew.
iii. Proposed Sec.  23.1310, Flight, Navigation, and Powerplant 
Instruments
    Proposed Sec.  23.1310 would require installed systems to provide 
the flightcrew member who sets or monitors flight parameters for the 
flight, navigation, and powerplant information necessary to do so 
during each phase of flight. Proposed Sec.  23.1310 would require this 
information include parameters and trends, as needed for normal, 
abnormal, and emergency operation, and limitations, unless an applicant 
showed the limitation would not be exceeded in all intended operations. 
Proposed Sec.  23.1310 would prohibit indication systems that integrate 
the display of flight or powerplant parameters to operate the airplane 
or are required by the operating rules of this chapter, from inhibiting 
the primary display of flight or powerplant parameters needed by any 
flightcrew member in any normal mode of operation. Proposed Sec.  
23.1310 would require these indication systems be designed and 
installed so information essential for continued safe flight and 
landing would be available to the flightcrew in a timely manner after 
any single failure or probable combination of failures.
    Proposed Sec.  23.1310 would capture the safety intent of current 
Sec. Sec.  23.1303, Flight and navigation instruments; 23.1305, 
Powerplant instruments; 23.1307, Miscellaneous equipment; 23.1311, 
Electronic display instrument systems; 23.1321, Arrangement and 
visibility; 23.1323, Airspeed indicating system; 23.1331, Instruments 
using a power source; and 23.1337, Powerplant instruments installation. 
The current requirements can be traced to CAR 3, specifically, CAR 
3.655, 3.661, 3.662, 3.675, 3.663, 3.668, 3.670, 3.671, 3.672, 3.673, 
and 3.674. These requirements, including Sec.  23.1311, which did not 
have a corresponding rule in CAR 3, were based on the technology and 
design solutions available at the time of their adoption. Although 
these requirements are appropriate for traditional systems and designs 
found in airplanes designed to these assumptions, they lack the 
flexibility to adopt current and anticipated technologies and design 
capabilities. Furthermore, the FAA proposes to remove prescriptive 
requirements from the rule that historically provided standardization 
for primary flight instruments and controls. The FAA still believes 
this standardization is important for traditionally designed airplane 
instrumentation. Accordingly, to reduce the potential for pilot error, 
the reliance on standards accepted by the Administrator would maintain 
standardization for traditional systems.
    The proposed regulations would require applicants to use a means of 
compliance based on consensus standards or other means accepted by the 
Administrator. However, new technology is already being approved that 
does not meet the traditional installation requirements and guidance. 
At the same time, this technology is proving equivalent or better than 
the traditional technology.\25\ Furthermore, the FAA believes that new 
systems, displays, and controls have the potential to reduce pilot 
workload with a direct safety benefit. By removing prescriptive 
requirements for the rules and allowing alternatives, the industry 
would be able to develop and certify safety-enhancing technology 
faster.
---------------------------------------------------------------------------

    \25\ See Accident and GA Safety reports from NTSB, AOPA Safety 
Foundation, and the General Aviation Joint Steering Committee (GA-
JSC) over the past 10 years.
---------------------------------------------------------------------------

    Proposed Sec.  23.1310 would not require limitations that could not 
be exceeded due to system design or physical properties to be shown 
because they would be useless information and result in clutter of the 
displays. Additionally, the FAA proposes removing the

[[Page 13491]]

prescriptive design requirement in current Sec.  23.1311 for the 
installation of secondary indicators. The safety intent is that a 
single failure or likely multiple failures would not result in the lack 
of all critical flight data. The design and installation of flight 
critical information should be such that the pilot could still fly 
partial panel after probable failures. The prescriptive redundancy 
requirements for installed secondary indicators have been too 
restrictive for airplanes limited to VFR operations. This has caused 
several applicants to request an ELOS finding from current Sec.  
23.1311(a)(5).
    The safety intent of Sec.  23.1311 is to provide crewmembers the 
ability to obtain the information necessary to operate the airplane 
safely in flight. Traditionally, the minimum was prescribed as 
airspeed, altimeter, and magnetic direction. The corresponding CAR 3 
rule is 3.655. The regulation is redundant with the operating rules, 
specifically, Sec. Sec.  91.205 and 135.149, as well as providing 
prescriptive design solutions that were assumed to achieve an 
acceptable level of safety. The prescriptive solutions precluded 
finding more effective or more economical paths to providing acceptable 
safety. Proposed Sec.  23.1310 would maintain the safety intent of the 
current rule.
    The FAA proposes consolidating the safety intent of current Sec.  
23.1305, Powerplant instruments, into proposed Sec.  23.1310, Flight, 
Navigation, and Powerplant Instruments. The safety intent of Sec.  
23.1305 is to provide crewmembers the ability to obtain the information 
necessary to operate the airplane and powerplant safely in flight. 
Traditionally, the minimum was prescribed, such as oil pressure, oil 
temperature, and oil quantity for all airplanes. The corresponding 
rules in CAR 3 are 3.655 and 3.675. Some of the regulation was 
redundant with the operating rules as well as providing prescriptive 
design solutions that were assumed to achieve an acceptable level of 
safety based on an assumption of powerplant types. The prescriptive 
solutions precluded finding more effective or more economical paths to 
providing acceptable safety. Additionally, they do not facilitate 
adoption of new technologies such as electric powered airplanes. The 
proposed Sec.  23.1310, Flight, Navigation, and Powerplant Instruments, 
would maintain the safety intent of the current rule.
iv. Proposed Sec.  23.1315, Equipment, Systems, and Installation
    Proposed Sec.  23.1315 would require an applicant to examine the 
design and installation of airplane systems and equipment, separately 
and in relation to other airplane systems and equipment, for any 
airplane system or equipment whose failure or abnormal operation has 
not been specifically addressed by another requirement in this part. 
Proposed Sec.  23.1315 would require an applicant to determine if a 
failure of these systems and equipment would prevent continued safe 
flight and landing and if any other failure would significantly reduce 
the capability of the airplane or the ability of the flightcrew to cope 
with adverse operating conditions. Proposed Sec.  23.1315 would require 
an applicant to design and install these systems and equipment, 
examined separately and in relation to other airplane systems and 
equipment, such that each catastrophic failure condition is extremely 
improbable, each hazardous failure condition is extremely remote, and 
each major failure condition was remote. Proposed Sec.  23.1315 would 
capture the safety intent found in portions of current Sec. Sec.  
23.691(g), Artificial stall barrier system; 23.729(f), Landing gear 
extension and retraction system; 23.735(d), Brakes; 23.1309, Equipment, 
systems, and installations; 23.1323, Airspeed indicating system; 
23.1325, Static pressure system; 23.1329, Automatic pilot system; 
23.1331, Instruments using a power source; 23.1337, Powerplant 
instruments installation; 23.1335, Flight director systems; 23.1353, 
Storage battery design and installation, 23.1357, Circuit protective 
devices; 23.1431, Electronic equipment; 23.1441(b), Oxygen equipment 
and supply; 23.1450(b), Chemical oxygen generators; 23.1451, Fire 
protection for oxygen equipment; and 23.1453, Protection of oxygen 
equipment from rupture. The current requirements can be traced to CAR 
3, specifically, 3.652, 3.663, 3.665, 3.667, 3.668, 3.670, 3.671, 
3.672, 3.673, 3.674, and 3.683. The foundation of the current Sec.  
23.1309 was derived from CAR 3.652, which stated that ``each item of 
equipment, which is essential to the safe operation of the airplane, 
shall be found by the Administrator to perform adequately the functions 
for which it is to be used . . .''. At that time, the airworthiness 
requirements were based on single-fault or fail-safe concepts. Due to 
the increased use of airplanes certificated under part 23 in the 1970s 
for all-weather operation, and a pilot's increased reliance on 
installed avionic systems and equipment, Sec.  23.1309, amendment 23-14 
(38 FR 31816, November 19, 1973), was issued to provide an acceptable 
level of safety for such equipment, systems, and installations. Section 
23.1309 introduced two main concepts: multiple failure combinations as 
well as a single failure had to be considered and there must be an 
inverse relationship between the likelihood of occurrence and the 
severity of consequences. The premise was that more severe consequences 
should happen less often.
    In addition to specific part 23 design requirements, proposed Sec.  
23.1315 requirements would apply to any equipment or system installed 
in the airplane. This proposed section addresses general requirements 
and is not intended to supersede any specific requirements contained in 
other part 23 sections. Proposed Sec.  23.1315 would not apply to the 
performance or flight characteristics requirements of subpart B, and 
structural loads and strength requirements of subpart C and D. However, 
it would apply to systems that complied with subpart B, C, D, and E 
requirements. As an example, proposed Sec.  23.1315 would not apply to 
an airplane's inherent stall characteristics, but would apply to a 
stick pusher system installed to attain stall compliance. Both current 
Sec.  23.1309 and proposed Sec.  23.1315 rules are not intended to add 
requirements to specific rules in part 23, but to account for the added 
complexity of integration and new technologies.
    This proposed regulation would require an engineering safety 
analysis to identify possible failures, interactions, and consequences, 
and would require an inverse relationship between the probability of 
failures and the severity of consequences. This would be accomplished 
by requiring all of the airplane's systems to be reviewed to determine 
if the airplane was dependent upon a system function for continued safe 
flight and landing and if a failure of any system on the airplane would 
significantly reduce the ability of the flightcrew to cope with the 
adverse operating condition. If the design of the airplane included 
systems that performed such functions, the systems would be required to 
meet standards that establish that maximum allowable probability of 
that failure. Section 23.1315 would impose qualitative, rather than 
quantitative probabilities of occurrence. As the FAA determined which 
quantitative values satisfied the proposed performance standards, it 
would share that information in FAA guidance or documented means of 
compliance appropriate to the certification levels of proposed Sec.  
23.5.

[[Page 13492]]

v. Proposed Sec.  23.1320, Electrical and Electronic System Lightning 
Protection
    Proposed Sec.  23.1320 would require, for an airplane approved for 
IFR operations, that each electrical or electronic system that 
performed a function, the failure of which would prevent the continued 
safe flight and landing of the airplane, be designed and installed such 
that the airplane level function continues to perform during and after 
the time the airplane is exposed to lightning. Proposed Sec.  23.1320 
would also require these systems automatically recover normal operation 
of that function in a timely manner after the airplane is exposed to 
lightning, unless the system's recovery conflicts with other 
operational or functional requirements of the system.
    Proposed Sec.  23.1320 would require each electrical and electronic 
system that performed a function, the failure of which would reduce the 
capability of the airplane or the ability of the flightcrew to respond 
to an adverse operating condition, be designed and installed such that 
the function recovers normal operation in a timely manner after the 
airplane is exposed to lightning.
    Proposed Sec.  23.1320 would capture the safety intent of current 
Sec.  23.1306, Electrical and electronic system lightning protection. 
The original adoption of the rule, first introduced as part of Sec.  
23.1309, was justified because there was an increased use of small 
airplanes in all-weather operations with an increasing reliance on 
complex systems and equipment in the modern, complex, high-performance 
airplanes.
    The FAA wants to facilitate the use of systems in new airplanes 
that reduce pilot workload and enhance safety. The current requirement 
that all aircraft regardless of their design or operational limitations 
meet the same requirements for lightning regardless of the potential 
threat has been burdensome for the traditional VFR-only airplane 
designs. Proposed Sec.  23.1320 would cover the airplanes with the 
greatest threat of lightning. In addition, the proposed language 
clarifies that the failure consequence of interest is at the airplane 
system level, which allows credit for design and installation 
architecture.
vi. Proposed Sec.  23.1325, High-Intensity Radiated Fields (HIRF) 
Protection
    Proposed Sec.  23.1325 would require that electrical and electronic 
systems that perform a function whose failure would prevent the 
continued safe flight and landing of the airplane, be designed and 
installed such that the airplane level function is not adversely 
affected during and after the time the airplane is exposed to the HIRF 
environment. Proposed Sec.  23.1325 would also require that these 
systems automatically recover normal operation of that function in a 
timely manner after the airplane is exposed to the HIRF environment, 
unless the system's recovery conflicts with other operational or 
functional requirements of the system. Proposed Sec.  23.1325, High-
Intensity Radiated Fields (HIRF) protection, would incorporate the 
safety intent of current Sec.  23.1308, High-intensity Radiated Fields 
(HIRF) protection.
    Before Sec.  23.1308, amendment 23-57 (72 FR 44016, August 6, 
2007), the requirements for HIRF protection were found in Sec.  
23.1309. The adoption of Sec.  23.1308 was justified because there was 
an increased use of complex systems and equipment, including engine and 
flight controls, in small airplanes. These systems are more susceptible 
to the adverse effects of operation in the HIRF environment.
    The electromagnetic HIRF environment results from the transmission 
of electromagnetic energy from radar, radio, television, and other 
ground-based, ship-borne, or airborne radio frequency transmitters. The 
HIRF environment changes as the number and types of transmitters 
change. During the 1990's, extensive studies were conducted to define 
the environment that then existed. The FAA codified this environment in 
amendment 23-57 in appendix J to part 23--HIRF Environments and 
Equipment HIRF Test Levels.
    Proposed Sec.  23.1325 would require the applicant to address the 
HIRF environment expected in service instead of solely relying on the 
HIRF environment codified in appendix J. The current appendix J to part 
23 would become a means of compliance as the accepted expected HIRF 
environment, until other levels were accepted by the Administrator. 
This would allow the test levels to match the current threat as the 
environment changes over time. Additionally, the proposed language 
would clarify that the failure consequence of interest is at the 
airplane level, which allows credit for design and installation 
architecture.
vii. Proposed Sec.  23.1330, System Power Generation, Storage, and 
Distribution
    Proposed Sec.  23.1330(a) would require that the power generation, 
storage, and distribution for any system be designed and installed to 
supply the power required for operation of connected loads during all 
likely operating conditions. Also, proposed Sec.  23.1330(b) would 
require the design installation ensure no single failure or malfunction 
would prevent the system from supplying the essential loads required 
for continued safe flight and landing. Proposed Sec.  23.1330 would 
also require the design and installation have enough capacity to supply 
essential loads, should the primary power source fail, for at least 30 
minutes for airplanes certificated with a maximum altitude of 25,000 
feet or less, and at least 60 minutes for airplanes certificated with a 
maximum altitude over 25,000 feet.
    Proposed Sec.  23.1330 would capture the safety intent of the 
current Sec. Sec.  23.1310, Power source capacity and distribution; 
23.1351, General; 23.1353, Storage battery design and installation; and 
23.1357, Circuit protective devices. The intent is to ensure airplane 
power generation and the related distribution systems are designed for 
adequate capacity and safe operation under anticipated use and in the 
event of a failure or malfunction.
viii. Proposed Sec.  23.1335, External and Cockpit Lighting
    Proposed Sec.  23.1335 would require an applicant to design and 
install all lights to prevent adverse effects on the performance of 
flightcrew duties. Proposed Sec.  23.1335 would require position and 
anti-collision lights, if installed, to have the intensities, flash 
rate, colors, fields of coverage, and other characteristics to provide 
sufficient time for another aircraft to avoid a collision. Proposed 
Sec.  23.1335 would require position lights, if installed, to include a 
red light on the left side of the airplane, a green light on the right 
side of the airplane, spaced laterally as far apart as practicable, and 
a white light facing aft, located on an aft portion of the airplane or 
on the wing tips.
    Proposed Sec.  23.1335 would require that an applicant design and 
install any taxi and landing lights, if required by operational rules, 
so they provide sufficient light for night operations. For seaplanes or 
amphibian airplanes, this section would also require riding lights to 
provide a white light visible in clear atmospheric conditions. 
Airplanes moored or maneuvering on water are by mairtime law considered 
watercraft; therefore, riding lights are required for seaplanes and 
amphibians during water operations.
    To encourage the installation of internal and external lighting 
systems with new safety enhancing technology and streamline the 
certification process, the FAA proposes removing most of the current 
prescriptive requirements and the detailed means of compliance for 
these requirements from current part 23.

[[Page 13493]]

The current prescriptive requirements would be replaced with 
performance-based requirements. The FAA expects that current means of 
compliance would continue to be used for the traditional airplane 
designs under part 23.
    Required lighting for the operation requested by an applicant would 
have to be installed and approved as part of the type design. The 
current rule requires that interior and exterior lighting function as 
intended without causing any safety hazard in normal operation. The 
proposed rule would require external lighting to make each airplane 
visible at night at a distance allowing each pilot to maneuver in 
sufficient time to avoid collision. The current rule specifies a 
specific amount of light illumination accounting for airframe 
obstructions. The FAA proposes removing this specified location and 
amount of illumination because it is more appropriate as means of 
compliance. The FAA does not consider small obstructions caused by 
airplane structure to be a safety issue.
    This section would capture the safety intent of current Sec. Sec.  
23.1381, Instrument lights, paragraph (c); 23.1383, Taxi and landing 
lights, paragraphs (a), (b) and (c); 23.1385, Position light system 
installation, paragraphs (a), (b) and (c); 23.1387, Position light 
dihedral angles; 23.1389, position light distribution and intensities; 
23.1391, Minimum intensities in the horizontal plane of position 
lights; 23.1393, Minimum intensities in any vertical plane of position 
lights; 23.1395, Maximum intensities in overlapping beams of position 
lights; 23.1397, color specifications; 23.1399, Riding light; and 
23.1401, Anticollision light system, paragraphs (a), (a)(1), (b), (c), 
(d), (e), and (f).
ix. Proposed Sec.  23.1400, Safety Equipment
    Proposed Sec.  23.1400 would require safety and survival equipment, 
required by the operating rules of this chapter, to be reliable, 
readily accessible, easily identifiable, and clearly marked to identify 
its method of operation.
    The FAA proposes requirements for safety equipment needed for 
emergency landings and ditching when required by operational rules, and 
removal of the duplicative rules that are found in current part 23. 
Required safety equipment would have to be installed, located, and 
accessible for use in an emergency, and secured against emergency 
landing accelerations. The proposed rule would require safety, 
ditching, and survival equipment, be reachable, plainly marked for 
operation, and not be damaged in survivable emergency landings.
    This section would capture the safety intent of current Sec. Sec.  
23.1411, Safety equipment--General, paragraphs (a) and (b)(1); and 
23.1415; Ditching equipment, paragraphs (a), (c), and (d).
x. Proposed Sec.  23.1405, Flight in Icing Conditions
    Proposed Sec.  23.1405 would require an applicant to demonstrate 
its ice protection system would provide for safe operation, if 
certification for flight in icing conditions is requested. Proposed 
Sec.  23.1405 would also require these airplanes to be protected from 
stalling when the autopilot is operating in a vertical mode. Proposed 
Sec.  23.1405 would require this demonstration be conducted in 
atmospheric icing conditions specified in part 1 of appendix C to part 
25 of this chapter, and any additional icing conditions for which 
certification is requested.
    Proposed Sec.  23.1405 would capture the safety intent of current 
Sec.  23.775(a) Windshields and windows, and Sec.  23.1419, Ice 
protection. Proposed Sec.  23.1405 would also increase safety by adding 
icing conditions beyond those specified in the current Sec.  23.1419. 
The proposed Sec.  23.1405 would only apply to airplanes seeking 
certification for flight in icing. The current Sec.  23.1419 only 
applies to airplanes seeking certification for flight in icing; 
however, ice protection systems can be certified without certification 
for flight in icing.
    The current ice protection system requirements in Sec.  23.1419(a) 
would be captured in proposed Sec.  23.1405(a)(1). The proposed rule 
would require an applicant to show systems are adequate in the icing 
conditions for which certification is requested. As in the current 
rule, ice protection systems would have to be shown to be adequate in 
the icing conditions of appendix C to part 25. Freezing drizzle and 
freezing rain icing conditions are optional icing conditions in which 
the airplane may be certificated to operate. These icing conditions, 
which the FAA added to appendix O to part 25 in amendment 25-140, are 
not being defined in proposed Sec.  23.230. The FAA determined that the 
definition of these optional icing conditions is more appropriate as a 
means of compliance. Ice crystal conditions are added to this proposal 
for certain air data probes to harmonize with EASA requirements.
    The Part 23 Icing ARC recommendations on activation and operation 
of ice protection systems would be used as a means of compliance to 
proposed Sec.  23.1405(a)(1). This proposal would satisfy the intent of 
NTSB Safety Recommendations A-07-14 and A-07-15.
    Proposed Sec.  23.1405(a)(2) is the Part 23 Icing ARC 
recommendation for airplanes certified under part 23 in icing and is 
based on NTSB safety recommendation A-10-12. The target for this 
proposed rule is older airplanes adding an autopilot for first time, 
modifying certain autopilots on airplanes with a negative service 
history in icing, or significant changes that affect performance or 
flight characteristics. Proposed Sec.  23.1405 would require, under the 
changed product rule, to add proposed Sec.  23.1405(a)(2) to the 
certification basis without requiring the remainder of Sec.  23.1405 
for certain autopilot modifications. For new airplanes, a stall warning 
system that complies with proposed Sec.  23.230 would comply with 
proposed Sec.  23.1405(a)(2). The vertical mode is a prescriptive 
requirement to limit the applicability. Simple autopilots such as a 
wing leveler would not be affected by this requirement. Numerous icing 
accidents have shown that unrecognized airspeed loss can occur with 
autopilots in altitude hold mode or vertical speed mode. Demonstration, 
as a means of compliance, may include design and/or analysis and does 
not mean natural icing flight tests are required.
xi. Proposed Sec.  23.1410, Pressurized System Elements
    Proposed Sec.  23.1410 would require the minimum burst pressure 
of--
     Hydraulic systems be at least 2.5 times the design 
operating pressure with the proof pressure at least 1.5 times the 
maximum operating pressure;
     Pressurization system elements be at least 2.0 times, and 
proof pressure be at least 1.5 times, the maximum normal operating 
pressure; and
     Pneumatic system elements be at least 3.0 times, and proof 
pressure be at least 1.5 times, the maximum normal operating pressure.

Additionally, this proposed section would also require that other 
pressurized system elements have pressure margins that take into 
account system design and operating conditions.
    This section would capture the safety intent of current Sec. Sec.  
23.1435, Hydraulic system, paragraphs (a)(4) and (b); 23.1437, 
Accessories for multiengine airplanes; and 23.1438, Pressurization and 
pneumatic systems, paragraphs (a) and (b).
xii. Proposed Sec.  23.1457, Cockpit Voice Recorders
    The FAA is not proposing to revise current Sec.  23.1457 because 
amendment

[[Page 13494]]

23-58 (73 FR 12542, March 7, 2008) and corrected on July 9, 2009 (74 FR 
32799), was written to standardize the cockpit voice recorder rules to 
address the NTSB's recommendations (70 FR 9752, February 28, 2005). The 
FAA agrees with NTSB recommendation numbers A-96-89, A-96-171, A-99-18, 
and parts of A-99-16 and A-99-17 and believes changing the current rule 
to remove prescriptive requirements could hinder the conduct of future 
accident investigations and be detrimental to aviation accident 
investigations.
xiii. Proposed Sec.  23.1459, Flight Data Recorders
    The FAA is not making any substantive changes to the current Sec.  
23.1459 because amendment 23-58 (73 FR 12541, March 7, 2008) was 
written to standardize the flight data recorder rules to address the 
NTSB's recommendations. The FAA agrees with NTSB recommendation numbers 
A-96-89, A-96-171, A-99-18, and parts of numbers A-99-16 and A-99-17 
and believes changing the current rule to remove prescriptive 
requirements could hinder the conduct of future accident investigations 
and be detrimental to aviation safety. Proposed Sec.  23.1459(a)(1), 
however, is amended to revise current references to Sec. Sec.  23.1323, 
Airspeed indicating system; 23.1325, Static pressure system; and 
23.1327, Magnetic direction indicator, as those sections are not 
contained in this NPRM.
xiv. Current Subpart F Regulations Relocated to Other Proposed Subparts
    The requirement currently in Sec.  23.1419(a) to comply with 
subpart B requirements to show safe operating capability is moved to 
proposed Sec.  23.230 as recommended by the Part 23 Icing ARC and Part 
23 Reorganization ARC.
    Ice protection of engine inlets would move to proposed Sec.  
23.940, Powerplant ice protection. The Part 23 Reorganization ARC had 
proposed that Sec.  23.1405 include these requirements, as well as 
heated pitot probe requirements for IFR airplanes. The FAA decided to 
separate them since compliance with proposed Sec. Sec.  23.940 and 
23.1300 would be required for all airplanes, whereas compliance with 
Sec.  23.1405 would be optional. The FAA wants to avoid potential 
confusion on TCDS interpretation as to whether an airplane is certified 
for flight in icing.
    The requirements currently in Sec.  23.1381, Instrument lights, 
paragraphs (a) and (b) would be relocated to proposed Sec.  23.1500, 
Flightcrew Interface. The requirements currently in Sec.  23.1411, 
Safety equipment--General, paragraph (b)(2) would be relocated to 
proposed Sec.  23.600, Emergency conditions.
xv. Removal of Subpart F of the Current Regulations
    When the FAA evaluated the current regulations, it determined that 
the prescriptive icing requirements in Sec. Sec.  23.1323, Airspeed 
indicating system, and 23.1325, Static pressure system, would be means 
of compliance to proposed Sec.  23.1405(a)(1). The current requirement 
for a heated pitot probe or an equivalent means on an IFR certified and 
a flight in icing conditions airplane in current Sec.  23.1323(d) would 
become a means of compliance for proposed Sec.  23.1300.
    The part 23 re-write ARC had recommended that proposed Sec.  
23.1405 include the requirement for a heated pitot probe on an IFR 
certified airplane, but the FAA determined this would be better 
addressed on a performance standard under proposed Sec.  23.1300, 
because proposed Sec.  23.1405 would only apply to icing certified 
airplanes. High altitude mixed phase and ice crystal conditions for 
certain high-performance airplanes, and ice protection requirements for 
stall warning and angle of attack would be means of compliance. The 
proposed standard would harmonize with EASA requirements.
    Current Sec.  23.1416 would be removed since the requirements for 
proper inflation and annunciation of operation of pneumatic boots would 
be covered on a performance basis in proposed Sec. Sec.  23.1300 and 
23.1305. This would reflect that all types of ice protection systems 
have annunciation requirements, and would eliminate unnecessary 
annunciations. The Part 23 Icing ARC recommended this approach.
    The analysis required in the current Sec.  23.1419(a), and all the 
requirements in the current Sec.  23.1419(b) and (c), would become 
means of compliance to proposed 1405(a) and would be removed.
    Current Sec.  23.1419(d) requires a means to detect critical ice 
accretions, including night lighting. The Part 23 Icing ARC had 
proposed a new Sec.  23.1403 to replace these ice detection 
requirements, which would also address the SLD detection required by 
proposed Sec.  23.230. These ice detection requirements are more 
appropriately addressed as a means of compliance to accommodate new 
technology. For example, visual ice accretion detection as a means to 
activate ice protection systems is no longer necessary on some designs, 
examples being primary ice detection systems and icing conditions 
detection systems. However, there would remain a requirement for pilots 
to detect severe ice accretions, and this would be addressed in 
proposed Sec.  23.230(b).
    When the FAA evaluated the current regulations, it determined that 
the prescriptive requirements in Sec. Sec.  23.1323, Airspeed 
indicating system; 23.1325, Static pressure system; 23.1327, Magnetic 
direction indicator; 23.1329, Automatic pilot system; 23.1335, Flight 
director systems; 23.1337, Powerplant instruments installation; 
23.1353, Storage battery design and installation; and 23.1357, Circuit 
protective devices, would be covered on a performance basis by proposed 
Sec. Sec.  23.1300; 23.1305; 23.1310; and 23.1315.
    Current Sec.  23.1401, Anticollision light system, paragraph (a)(2) 
would be removed as introductory material. Current Sec.  23.1415, 
ditching equipment, paragraph (b) would be removed but could serve as a 
means of compliance. The current Sec. Sec.  23.1435, Hydraulic systems, 
paragraphs, (a), (a)(1), (a)(2), (a)(3), and (c); 23.1438, 
Pressurization and pneumatic systems, paragraph (c), would be removed 
as prescriptive design and means of compliance. Current Sec.  23.1443, 
Minimum mass flow of supplemental oxygen, paragraph (d) would be 
removed as a definition. Current Sec.  23.1445, paragraph (e) would be 
removed as redundant to current Sec.  91.211, paragraph (a)(3).
7. Subpart G--Flightcrew Interface and Other Information
a. General Discussion
    The FAA proposes to expand subpart G to address not only current 
operating limitations and information, but also the concept of 
flightcrew interface. Based on current technologies, the FAA 
anticipates that new airplanes will heavily rely on automation and 
systems that require new and novel pilot or flightcrew interface. The 
FAA is proposing to address the pilot interface issues found in 
subparts D and F with proposed Sec.  23.1500. Otherwise, subpart G 
retains the safety requirements from the current rules without change. 
Refer to appendix 1 of this preamble for a cross-reference table 
detailing how the current regulations are addressed in the proposed 
part 23 regulations.
b. Specific Discussion of Changes
i. Proposed Sec.  23.1500, Flightcrew Interface
    Proposed Sec.  23.1500 would require the pilot compartment and its 
equipment to allow the pilot(s) to perform their duties, including 
taxi, takeoff, climb,

[[Page 13495]]

cruise, descent, approach, and landing; and perform any maneuvers 
within the operating envelope of the airplane, without excessive 
concentration, skill, alertness, or fatigue. Proposed Sec.  23.1500 
would also require an applicant to install flight, navigation, 
surveillance, and powerplant controls and displays so qualified 
flightcrew could monitor and perform all tasks associated with the 
intended functions of systems and equipment in order to make the 
possibility that a flightcrew error could result in a catastrophic 
event highly unlikely. Proposed Sec.  23.1500 would capture the safety 
intent of current part 23 rules that are directly related to the pilot 
or flightcrew interface with the airplane. Interfaces include controls, 
displays, and visibility requirements.
    Current and anticipated technologies that affect how the pilot 
interfaces with the airplane are expected to expand faster than other 
technologies. The FAA believes that significant safety improvements can 
result from the evolution of how the pilot interfaces with the 
airplane. Pilot workload is a major factor in causing accidents, but it 
is almost impossible to connect workload-related mistakes to an 
accident after the accident has happened. Evidence from large airplane 
accidents, where we have recorded data as well as research, points to 
the importance of the pilot interface and associated mistakes as causal 
factors in aircraft accidents. The smart use of automation and phase-
of-flight-based displays could reduce pilot workload and increase pilot 
awareness.
    The converse is also true. Equipment is becoming available faster 
than manufacturers and the FAA can evaluate it. Determining the safety 
risks and recognizing the safety benefits of new technology available 
to the pilot is important. For this reason, the proposed language 
addresses the safety issues of the current Sec. Sec.  23.699, Wing flap 
position indicator; 23.745 Nose/Tail wheel steering, 23.1303, Flight 
and navigation instruments, paragraph (g)(3); 23.1321, Arrangement and 
visibility, paragraphs (a),(b),(d), and (e); 23.1311, Electronic 
display instrument systems, paragraphs (a)(6) and (7); 23.771, Pilot 
compartment, paragraph (a), 23.773(a) Pilot compartment view, 23.777, 
Cockpit controls; 23.779, Motion and effect of cockpit controls; and 
23.781, Cockpit control knob shape; are addressed in proposed Sec.  
23.1500(a) and (b). The proposed language would allow the FAA to 
rapidly evaluate new equipment for concentration, skill, alertness, and 
fatigue against pilot workload as is current practice. More 
importantly, the FAA would remove the prescriptive requirements from 
the current rules to allow for alternative approaches to pilot 
interface that would reduce pilot workload or increase safety.
ii. Proposed Sec.  23.1505, Instrument Markings, Control Markings, and 
Placards
    Proposed Sec.  23.1505 would require each airplane to display in a 
conspicuous manner any placard and instrument marking necessary for 
operation. Proposed Sec.  23.1505 would also require an applicant to 
clearly mark each cockpit control, other than primary flight controls, 
as to its function and method of operation and include instrument 
marking and placard information in the AFM. The consolidation of these 
sections appears large, but many of these sections contain one 
prescriptive requirement that, in many cases, is based on traditional 
airplanes, instruments, and equipment.
iii. Proposed Sec.  23.1510, Airplane Flight Manual
    Proposed Sec.  23.1510 would require an applicant to furnish an AFM 
with each airplane that contains the operating limitations and 
procedures, performance information, loading information, and any other 
information necessary for the operation of the airplane.
    The proposed rules capture the prescriptive list of information 
that is considered necessary for the operation of the traditional 
airplanes. The current rules contain very prescriptive and detailed 
information. Furthermore, that level of detail assumes a traditional 
airplane configuration and operation. The FAA proposes to remove this 
detail from the rule because it is more appropriate as means of 
compliance. Currently, the majority of airplanes certificated under 
part 23 already use an industry standard to develop their AFMs--General 
Aviation Manufactures Association Specification 1, Specification for 
Pilot's Operating Handbook.\26\ The FAA already accepts this industry 
standard for many airplanes certificated under part 23 because it 
includes the information that is currently required in part 23. The FAA 
believes that allowing alternative approaches to information would 
facilitate new technology integration into airplanes certified under 
part 23.
---------------------------------------------------------------------------

    \26\ See www.regulations.gov (Docket #FAA-2015-1621).
---------------------------------------------------------------------------

    The proposed Sec.  23.1510(d) would capture the safety intent of 
the current Sec. Sec.  23.1505, Airspeed limitations, thru 23.1527, 
Maximum operating altitude, specific to operating limitations and other 
limitations and information necessary for safe operation.
iv. Proposed Sec.  23.1515, Instructions for Continued Airworthiness
    Proposed Sec.  23.1515 would require an applicant to prepare 
Instructions for Continued Airworthiness in accordance with proposed 
appendix A to this part, that are acceptable to the Administrator, 
prior to the delivery of the first airplane or issuance of a standard 
certification of airworthiness, whichever occurs later. This proposed 
section would capture the current Sec.  23.1529 without change. The FAA 
proposes renaming Appendix G to Part 23--Instructions for Continued 
Airworthiness, to Appendix A to Part 23--Instructions for Continued 
Airworthiness.
8. Appendices to Part 23
a. General Discussion
    Many of the appendices to part 23 contain information that the FAA 
believes would be more appropriate as a means of compliance, with the 
exception of Appendix G to Part 23-Instructions for Continued 
Airworthiness. Appendices A, B, C, D, E, F, H, and J would be removed 
and appendix G would be renamed Appendix A--Instructions for Continued 
Airworthiness.
b. Specific Discussion of Changes
i. Proposed Appendix A to Part 23--Instructions for Continued 
Airworthiness
    The FAA proposes renaming Appendix G to Part 23--Instructions for 
Continued Airworthiness, as Appendix A to Part 23--Instructions for 
Continued Airworthiness.
ii. Removal of Appendices to Part 23
    Appendix A to Part 23--Simplified Design Load Criteria. The FAA 
proposes to remove this appendix because the content is more 
appropriate for inclusion in methods of compliance.
    Appendix B to Part 23--[Reserved]. The FAA proposes to remove this 
appendix because it has been reserved since amendment 23-42. There is 
no reason to include this appendix in the proposed revision to part 23.
    Appendix C to Part 23--Basic Landing Conditions. The FAA proposes 
to remove this appendix because the content is more appropriate for 
inclusion in methods of compliance.
    Appendix D to Part 23--Wheel Spin-Up and Spring-Back Loads. The FAA 
proposes to remove this appendix because the content is more 
appropriate for inclusion in methods of compliance.
    Appendix E to Part 23--[Reserved]. The FAA proposes to remove this

[[Page 13496]]

appendix because the current appendix is reserved and contains no 
information.
    Appendix F to Part 23--Test Procedure. The FAA proposes to remove 
this appendix because this is purely a means of showing compliance for 
materials that must comply with self-extinguishing flammability 
requirements.
    Appendix H to Part 23--Installation of an Automatic Power Reserve 
(APR) System. The FAA proposes to remove this appendix because the FAA 
believes that the detailed and prescriptive language of appendix H is 
more appropriate as means of compliance.
    Appendix I to Part 23--Seaplane Loads. The FAA proposes to remove 
this appendix because the content is more appropriate for inclusion in 
methods of compliance.
    Appendix J to Part 23--HIRF Environments and Equipment HIRF Test 
Levels. The accepted HIRF environment is codified as appendix J to part 
23--HIRF Environments and Equipment HIRF Test Levels. The proposed 
language in Sec.  23.1325 would revise this to the expected HIRF 
environment. The current appendix J to part 23 would remain an accepted 
expected HIRF environment until the Administrator accepted other 
levels. Any new expected HIRF environment would be found in FAA 
guidance material or other standards accepted by the Administrator. 
This would allow the certification requirement to match the current 
threat agreed to over time. Additionally, the proposed language would 
clarify that the failure consequence of interest is at the airplane 
level, which allows credit for design and installation architecture.

B. Miscellaneous Amendments (Sec. Sec.  21.9, 21.17, 21.24, 21.35, 
21.50, 21.101, 35.1, 35.37, 91.205, 91.313, 91.323, 91.531, 121.310, 
135.169, and Appendix E to Part 43)

1. Production of Replacement and Modification Articles (Sec.  21.9)
    The FAA proposes amending Sec.  21.9 by adding paragraph (a)(7) to 
provide applicants with an alternative method to obtain FAA approval to 
produce replacement and modification articles that are reasonably 
likely to be installed on type certificated aircraft. We also propose 
to revise paragraphs (b) and (c) to specify these articles would be 
suitable for use in a type certificated product. These proposed changes 
would allow an applicant to submit production information for a 
specific article, but would not require the producer of the article to 
apply for approval of the article's design or obtain approval of its 
quality system. Accordingly, approval to produce a modification or 
replacement article under proposed Sec.  21.9(a)(7) would not 
constitute a production approval as defined in Sec.  21.1(b)(6). The 
FAA intends to limit use of this procedure to articles whose improper 
operation or failure would not cause a hazard. Approval would be 
granted to the applicant on a case-by-case basis, specific to the 
installation proposed, accounting for potential risk and considering 
the safety continuum.
2. Designation of Applicable Regulations (Sec.  21.17)
    The FAA proposes amending Sec.  21.17, by removing the reference to 
Sec.  23.2, because this section would be deleted. The requirements in 
Sec.  23.2 are currently addressed in the operational rules. Since 
Sec.  23.2 is a retroactive rule, it is appropriate for the requirement 
to be in the operating rules. As a result, the FAA also proposes 
amending Sec.  91.205 by revising paragraphs (b)(13) and (b)(14) to 
ensure removing this requirement would not have any effect on the 
existing fleet.
3. Issuance of Type Certificate: Primary Category Aircraft (Sec.  
21.24)
    The FAA proposes amending Sec.  21.24 by revising paragraph 
(a)(1)(i) to modify the phrase as defined by Sec.  23.49 to include 
reference to amendment 23-62 (76 FR 75736, December 2,2011), effective 
on January 31, 2012. This revision is necessary to maintain a complete 
definition of stall speed in this section, as the current Sec.  23.49 
would be removed from the proposed rule.
4. Flight Tests (Sec.  21.35)
    The FAA proposes amending Sec.  21.35 by revising paragraph (b)(2) 
to delete the reference to reciprocating engines and expanding the 
exempted airplanes to include all low-speed part 23 airplanes 6,000 
pounds or less. This proposed change would align the requirements for 
function and reliability testing with the proposed changes in part 23 
that do not distinguish between propulsion types. This change would 
allow the FAA flexibility to address new propulsion types based on the 
changes to part 23.
5. Instructions for Continued Airworthiness and Manufacturer's 
Maintenance Manuals Having Airworthiness Limitations Sections (Sec.  
21.50)
    The FAA proposes amending Sec.  21.50(b) to reference Sec.  23.1515 
rather than Sec.  23.1529. This change is editorial and would align 
with the proposed part 23 numbering convention.
6. Designation of Applicable Regulations (Sec.  21.101)
    The FAA proposes amending Sec.  21.101 by removing the reference to 
Sec.  23.2 as this section is proposed to be deleted and is addressed 
in the operating rules, and to refer to the proposed part 23 
certification levels in paragraph (c). The current 6,000-pound 
reference would be augmented by the inclusion of simple airplanes, 
certification level 1 low-speed airplanes, and certification level 2 
low-speed airplanes, in order to align the current rules with the 
proposed part 23 certification levels.
    Additionally, the FAA recognizes that it may be impractical for 
airplanes certified under part 23, amendment 23-62, or prior 
amendments, to move up to the latest amendment for modifications. 
Section 21.101 would not be revised to address this circumstance, as 
this section allows for certification at a lower amendment level if 
meeting the current amendment is impractical. This current provision 
would allow for compliance to the certification requirements at 
amendment 23-62 or earlier when compliance to the latest amendment of 
part 23 was determined by the FAA to be impractical.
7. Applicability (Sec.  35.1)
    The FAA proposes amending Sec.  35.1 by replacing the reference to 
Sec.  23.907 with proposed Sec.  23.905(c).
8. Fatigue Limits and Evaluation (Sec.  35.37)
    The FAA proposes amending Sec.  35.37 by replacing the reference to 
Sec.  23.907 with proposed Sec.  23.905(c).
9. Altimeter System Test and Inspection (Appendix E to Part 43)
    The FAA proposes amending appendix E to part 43 by revising 
paragraph (a)(2) to conform with proposed part 23 changes. This 
proposed change would affect owners and operators of part 23 
certificated airplanes in controlled airspace under instrument flight 
rules who must comply with Sec.  91.411. Concurrent with this rule 
change, AC 43-6, Altitude Reporting Equipment and Transponder System 
Maintenance and Inspection Practices, would be revised to include a 
static pressure system proof test acceptable to the Administrator. 
Additionally, while reviewing appendix E to part 43, paragraph (a)(2), 
we noted that it remains silent on parts 27 and 29 rotorcraft and Civil 
Air Regulations certificated aircraft. The static pressure system proof 
test in AC 43-6 ensures the accuracy needed to meet Sec.  91.411 
requirements.

[[Page 13497]]

10. Powered Civil Aircraft With Standard Category U.S. Airworthiness 
Certificates: Instrument and Equipment Requirements (Sec.  91.205)
    The FAA proposes amending Sec.  91.205 by revising paragraphs 
(b)(13) and (b)(14) to include the potential for allowing other 
approved restraint systems. Additionally, paragraph (b)(14) refers to 
Sec.  23.561(b)(2), which would be retitled in the proposed revision 
for structural strength limits and would be addressed in the means of 
compliance. Section 91.205(b)(16) would be deleted and incorporated 
into (b)(14) with no additional requirements. The part 23 proposal 
would delete references to utility and acrobatic categories, as they 
would be incorporated into the normal categories that would be 
redefined into performance-based standards.
11. Restricted Category Civil Aircraft: Operating Limitations (Sec.  
91.313)
    The FAA proposes amending Sec.  91.313(g) to include the potential 
for allowing other approved restraint systems. Additionally, paragraph 
(g) includes a regulatory reference to Sec.  23.561(b)(2), which would 
be retitled in the proposed revision as Sec.  23.600, which would be 
accompanied by accepted means of compliance. Approval for a shoulder 
harness or restraint system, therefore, would require withstanding the 
static inertia loads specified in Sec.  23.600 during emergency 
conditions.
12. Increased Maximum Certification Weights for Certain Airplanes 
Operated in Alaska (Sec.  91.323)
    The FAA proposes amending Sec.  91.323 by removing reference to 
Sec.  23.337 because this section would be revised and consolidated 
with other structural requirements. The relevant prescriptive 
requirement(s) maneuvering load factors found in Sec.  23.337 would be 
added to the regulation in Sec.  91.323(b)(3).
13. Second in Command Requirements (Sec.  91.531)
    The FAA proposes amending Sec.  91.531(1) and (3) to incorporate 
the new risk and performance levels proposed in this NPRM. The FAA 
proposes deleting the reference to utility, acrobatic, and commuter 
categories in part 23. Other divisions would be used to define levels 
of certification for normal category airplanes. This proposed amendment 
would ensure airplanes certificated in the commuter category in the 
past and airplanes certificated in the future under the proposed part 
23 airworthiness and performance levels would be addressed in this 
rule.
14. Additional Emergency Equipment (Sec.  121.310)
    The FAA proposes amending Sec.  121.310(b)(2)(iii) to reflect the 
reference to Sec.  23.811(b), effective June 16, 1994. This would be an 
update to the reference for conformity only. This amendment would make 
no change to the requirements of the rule.
15. Additional Airworthiness Requirements (Sec.  135.169)
    The FAA proposes amending Sec.  135.169(b) by deleting the terms, 
``reciprocating-engine or turbopropeller-powered''. The current rule 
limits operation under this part to reciprocating-engine or 
turbopropeller-powered small airplanes. By amending the paragraph as 
proposed, other small airplanes, regardless of propulsion type and 
including turbojet-powered, would potentially be considered for 
certification under this part.
    The FAA also proposes to allow a small airplane in normal category, 
in Sec.  135.169(b)(8), to operate within the rules governing commuter 
and on demand operations. This action would be necessary as a result of 
the proposed part 23 rules which would sunset the commuter category for 
newly type certificated airplanes and create a normal category, 
certification level 4 airplane as equivalent to the commuter category 
by applying to 10-19 passengers. This proposed amendment would allow 
for the consideration of the new category airplane and to ensure a 
continued higher level of safety for commercial operations. Because of 
the ground-breaking nature of the part 23 proposals, the associated 
adjustment to performance-based airworthiness standards in future 
airplane designs and manufacturing, and the myriad of potential 
possibilities for attaining a means of compliance for airplane type 
certification, the FAA proposes to require the new normal category 
certification level 4 airplanes to meet the current airworthiness and 
performance standards of the commuter category found in part 23 thru 
amendment 23-62. These standards are envisioned to remain as 
requirements for the new normal category certification level 4 
airplanes into the near-term future, but not the long-term. It is 
intended that once the new part 23 requirements have proven successful 
with the new normal category certification levels 1, 2, and 3 
airplanes, the FAA would reconsider normal category certification level 
4 airplanes for part 135 commercial operations.

VII. Regulatory Notices and Analyses

A. Regulatory Evaluation Summary

    Changes to Federal regulations must undergo several economic 
analyses. First, Executive Order 12866 and Executive Order 13563 direct 
that each Federal agency shall propose or adopt a regulation only upon 
a reasoned determination that the benefits of the intended regulation 
justify its costs. Second, the Regulatory Flexibility Act of 1980 (Pub. 
L. 96-354) requires agencies to analyze the economic impact of 
regulatory changes on small entities. Third, the Trade Agreements Act 
(Pub. L. 96-39) prohibits agencies from setting standards that create 
unnecessary obstacles to the foreign commerce of the United States. In 
developing U.S. standards, this Trade Act requires agencies to consider 
international standards and, where appropriate, that they be the basis 
of U.S. standards. Fourth, the Unfunded Mandates Reform Act of 1995 
(Pub. L. 104-4) requires agencies to prepare a written assessment of 
the costs, benefits, and other effects of proposed or final rules that 
include a Federal mandate likely to result in the expenditure by State, 
local, or tribal governments, in the aggregate, or by the private 
sector, of $100 million or more annually (adjusted for inflation with 
base year of 1995). This portion of the preamble summarizes the FAA's 
analysis of the economic impacts of this proposed rule. We suggest 
readers seeking greater detail read the full regulatory evaluation, a 
copy of which we have placed in the docket for this rulemaking.
    In conducting these analyses, FAA has determined that this proposed 
rule: (1) Would have benefits that justify its costs, (2) would not be 
an an economically ``significant regulatory action'' as defined in 
section 3(f) of Executive Order 12866, (3) would be ``significant'' as 
defined in DOT's Regulatory Policies and Procedures; (4) would have a 
significant positive economic impact on small entities; (5) would not 
create unnecessary obstacles to the foreign commerce of the United 
States; and (6) would not impose an unfunded mandate on state, local, 
or tribal governments, or on the private sector by exceeding the 
threshold identified above. These analyses are summarized below.
1. Total Benefits and Costs of This Rule
    The following table shows the estimated benefits and costs of the 
proposed rule. The major factors driving the expected costs of this 
proposal are the additional training tasks, database development, and 
documentation to

[[Page 13498]]

FAA and industry part 23 certification engineers. Benefits consist of 
safety benefits from preventing stall and spin accidents and savings 
from reducing the number of special conditions, exemptions, and 
equivalent levels of safety. If the proposed rule saves only one human 
life by improving stall characteristics and stall warnings, that alone 
would result in benefits outweighing the costs.

             Estimated Benefits and Costs From 2017 to 2036
                            [2014 $ Millions]
------------------------------------------------------------------------
                                                  Safety benefits + cost
                                      Costs          savings = total
                                                         benefits
------------------------------------------------------------------------
Total..........................            $3.9  $19.6 + $12.6 = $32.2.
Present value..................            $3.9  $6.2 + $5.8 = $12.0.
------------------------------------------------------------------------

2. Who is potentially affected by this rule?
    The proposal would affect U.S. manufacturers and operators of new 
part 23 type certificated airplanes.
3. Assumptions
    The benefit and cost analysis for the regulatory evaluation is 
based on the following factors/assumptions:

     The analysis is conducted in constant dollars with 2014 
as the base year.
     The final rule would be effective in 2017.
     The primary analysis period for costs and benefits 
extends for 20 years, from 2017 through 2036. This period was 
selected because annual costs and benefits will have reached a 
steady state by 2036.
     Future part 23 type certifications and deliveries are 
estimated from historical part 23 type certifications and 
deliveries.
     Costs for the new part 23 type certifications 
forecasted in the ``Fleet Discussion'' section of the regulatory 
evaluation would occur in year 1 of the analysis interval.
     Airplane deliveries from the forecasted part 23 type 
certificates would start in year 5 of the analysis interval.
     The FAA uses a seven percent discount rate for the 
benefits and costs as prescribed by OMB in Circular A-4.
     The baseline for estimating the costs and benefits of 
the proposed rule would be part 23, through amendment 62.
     The FAA estimates 335 FAA part 23 certification 
engineers would require additional training as a result of this 
proposal. The FAA assumes that the same number of industry part 23 
certification engineers would also require additional training as a 
result of this proposal.
     The FAA estimates that this proposal would add 16 hours 
of training to FAA and industry part 23 certification engineers.
     Since this training program would be on-line, we 
estimate no travel costs for the engineers.
     FAA pay-band tables and the Bureau of Labor Statistics 
(BLS) determine the hourly wages used to estimate the costs to the 
FAA and applicants.
     Using the U.S. Department of Transportation guidance, 
the wage multiplier for employee benefits is 1.17.\27\
---------------------------------------------------------------------------

    \27\ On January 30, 2014, the DOT published a memo on 
``Estimating Total Costs of Compensation Based on Wage Rates or 
Salaries.'' The memo directs the FAA that when a rule requires 
incremental hours per existing employee, the wage/salary multiplier 
is of smaller magnitude because not all categories of employer 
provided benefits increase with additional hours worked by an 
individual employee.
---------------------------------------------------------------------------

4. Benefits of This Rule
    The major safety benefit of this proposed rule is to add stall 
characteristics and stall warnings that would result in airplane 
designs that are more resistant to depart controlled flight 
inadvertently. The largest number of accidents for small airplanes is a 
stall or departure-based LOC in flight. This proposal would also have 
cost savings by streamlining the certification process and encouraging 
new and innovative technology. Streamlining the certification process 
would reduce the issuance of special conditions, exemptions, and 
equivalent level of safety findings.
5. Costs of This Rule
    The proposed rules major costs are the engineer training costs and 
the certification database creation costs. Additional costs would also 
accrue from the proposed controllability and stall sections that would 
increase scope over current requirements and manual upgrade costs.
    In the following table, we summarize the total estimated compliance 
costs by category. The FAA notes that since we assumed that all costs 
occurred in Year 1 of the analysis interval, the 2014-dollar costs 
equal the present value costs.

                     Total Cost Summary by Category
------------------------------------------------------------------------
                                                            Total costs
                      Type of cost                          (2014$) and
                                                               P.V.
------------------------------------------------------------------------
Sec.   23.200 Controllability...........................        $276,939
Sec.   23.215 Stall characteristics, stall warning, and          500,000
 spins..................................................
Engineer Training Costs.................................       1,149,418
Certification Database Costs............................       1,293,750
Manual Upgrade Costs....................................         700,000
                                                         ---------------
    Total Costs.........................................       3,920,106
------------------------------------------------------------------------
* These numbers are subject to rounding error.

B. Initial Regulatory Flexibility Determination

    The Regulatory Flexibility Act of 1980 (Pub. L. 96-354) (RFA) 
establishes ``as a principle of regulatory issuance that agencies shall 
endeavor, consistent with the objectives of the rule and of applicable 
statutes, to fit regulatory and informational requirements to the scale 
of the businesses, organizations, and governmental jurisdictions 
subject to regulation. To achieve this principle, agencies are required 
to solicit and consider flexible regulatory proposals and to explain 
the rationale for their actions to assure that such proposals are given 
serious consideration.'' The RFA covers a wide-range of small entities, 
including small businesses, not-for-profit organizations, and small 
governmental jurisdictions.
    Agencies must perform a review to determine whether a rule will 
have a significant economic impact on a substantial number of small 
entities. If the agency determines that it will, the agency must 
prepare a regulatory flexibility analysis as described in the RFA.
    The FAA believes that this proposed rule could have a significant 
economic impact on a substantial number of entities because we believe 
that this rule could enable the creation of new part 23 type 
certificates and new manufacturers. The FAA has been working with U.S. 
and foreign small aircraft manufacturers since 2007 to review the life 
cycle of part 23 airplanes and determine what needed improvement.
    The purpose of this analysis is to provide the reasoning underlying 
the FAA determination.

[[Page 13499]]

    Under Section 603(b) of the RFA, the initial analysis must address:

     Description of reasons the agency is considering the 
action;
     Statement of the legal basis and objectives for the 
proposed rule;
     Description of the record keeping and other compliance 
requirements of the proposed rule;
     All federal rules that may duplicate, overlap, or 
conflict with the proposed rule;
     Description and an estimated number of small entities 
to which the proposed rule will apply; and
     Describe alternatives considered.

1. Reasons Why the Rule Is Being Proposed
    The FAA proposes this action to amend the airworthiness standards 
for new part 23 type certificated airplanes to reflect the current 
needs of the small airplane industry, accommodate future trends, 
address emerging technologies, and enable the creation of new part 23 
manufacturers and new type certificated airplanes. The proposed changes 
to part 23 are necessary to eliminate the current workload of 
exemptions, special conditions, and equivalent levels of safety 
findings necessary to certificate new part 23 airplanes. These proposed 
part 23 changes would also promote safety by enacting new regulations 
for controllability and stall standards and promote new technologies in 
part 23 airplanes.
2. Statement of the Legal Basis and Objectives
    The FAMRA required the Administrator, in consultation with the 
aviation industry, to assess the aircraft certification and approval 
process. In addition, the SARA directs the FAA to create performance-
based regulations for small airplanes and provide for the use of 
industry developed consensus standards to allow flexibility in the 
certification of new technology.
    Accordingly, this proposed rule would amend Title 14 of the Code of 
Federal Regulations to revise the airworthiness standards for small 
airplanes by removing current prescriptive design requirements and 
replacing those requirements with risk and performance-based 
airworthiness standards.
    The FAA's authority to issue rules on aviation safety is found in 
Title 49 of the United States Code. Subtitle I, Section 106 describes 
the authority of the FAA Administrator. Subtitle VII, Aviation 
Programs, describes in more detail the scope of the agency's authority. 
This rulemaking is promulgated under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701. Under that section, 
the FAA is charged with promoting safe flight of civil airplanes in air 
commerce by prescribing minimum standards required in the interest of 
safety for the design and performance of airplanes. This regulation is 
within the scope of that authority because it prescribes new 
performance-based safety standards for the design of normal category 
airplanes.
3. Projected Reporting, Recordkeeping and Other Requirements
    The FAA expects no more than minimal new reporting and 
recordkeeping compliant requirements would result from this proposed 
rule because the prescriptive nature of part 23 would be in other FAA 
approved documents where future technology can readily be adopted into 
the regulatory framework. The FAA requests comment regarding the 
anticipated reduction in paperwork and recordkeeping burdens that may 
result from this revision.
4. Overlapping, Duplicative, or Conflicting Federal Rules
    The proposed rule would not overlap, duplicate, or conflict with 
existing federal rules.
5. Estimated Number of Small Firms Potentially Impacted
    Under the RFA, the FAA must determine whether a proposed or final 
rule significantly affects a substantial number of small entities. This 
determination is typically based on small entity size and cost 
thresholds that vary depending on the affected industry. Using the size 
standards from the Small Business Administration for Air Transportation 
and Aircraft Manufacturing, we defined companies as small entities if 
they have fewer than 1,500 employees.\28\
---------------------------------------------------------------------------

    \28\ 13 CFR 121.201, Size Standards Used to Define Small 
Business Concerns, Sector 48-49 Transportation, Subsector 481 Air 
Transportation.
---------------------------------------------------------------------------

    There are seven U.S. owned aircraft manufacturers who delivered 
part 23 airplanes in the 1998-2013 analysis interval. These 
manufacturers are Adam, American Champion, Cessna, Hawker Beechcraft, 
Maule, Quest, and Sino-Swearingen.
    Using information provided by the Internet filings and news 
reports, manufacturers that are subsidiary businesses of larger 
businesses, manufacturers that are foreign owned, and businesses with 
more than 1,500 employees were eliminated from the list of small 
entities. Cessna and Hawker Beechcraft are businesses with more than 
1,500 employees. For the remaining businesses, we obtained company 
revenue and employment from the above sources.
    The base year for the final rule is 2014. Although the FAA 
forecasts traffic and air carrier fleets, we cannot determine either 
the number of new entrants or who will be in the part 23 airplane 
manufacturing business in the future. Therefore, we use current U.S. 
part 23 airplane manufacturers' revenue and employment in order to 
determine the number of small entities this proposed rule would affect.
    The methodology discussed above resulted in the following list of 
five U.S. part 23 airplane manufacturers, with less than 1,500 
employees.

------------------------------------------------------------------------
                                             Number of
              Manufacturer                   employees    Annual revenue
------------------------------------------------------------------------
Part 23 Manufacturer 1..................               2        $110,000
Part 23 Manufacturer 2..................              65       7,000,000
Part 23 Manufacturer 3..................              75      35,000,000
Part 23 Manufacturer 4..................             175      34,000,000
Part 23 Manufacturer 5..................               2          97,000
------------------------------------------------------------------------

    From this list of small entity U.S. airplane manufacturers, there 
are three manufacturers currently producing part 23 reciprocating 
engine airplanes; only one manufacturer producing turboprops and only 
one producing turbojets. The single manufacturer producing a part 23 
turbojet has not delivered an airplane since 2009 and is still working 
on

[[Page 13500]]

acquiring the means to start up its production line again. One of the 
manufacturers producing a part 23 reciprocating engine airplane has not 
delivered an airplane since 2007 and is working on acquiring the means 
to start up their production line again. The FAA is not aware that 
either of these manufacturers is considering a new airplane for part 23 
type certification in the future and therefore this proposed rulemaking 
would most likely not add costs to these two manufacturers because the 
proposed rule only affects new part 23 type certificates.
    For the remaining two reciprocating engine part 23 airplane 
manufacturers, their last type certificates were issued in 1961 and 
1970. The 1961 type certificate was issued for the only airplane this 
manufacturer produces and the manufacturer with the 1970 type 
certificate produces one other airplane that was type certificated in 
1941. The last small entity manufacturer produces only turboprop 
airplanes and it started delivering airplanes in 2007. Again, the FAA 
is not aware that any of these manufacturers is considering a new 
airplane for part 23 type certification in the future and therefore 
this proposed rulemaking would most likely not add costs for it.
    While this rulemaking may enable the creation of new manufacturers, 
the FAA is not aware of any new small entity part 23 manufacturers who 
want a type certification in the future for a new part 23 airplane. 
However, by simplifying and lowering the costs for certification of new 
small airplanes, barriers to entry may be lowered and thus new 
manufacturers may emerge.
6. Cost and Affordability for Small Entities
    In 2009, a joint FAA/industry team finalized the Part 23 CPS. This 
proposed rulemaking resulted from this study by the recommendation to 
use consensus standards to supplement the regulatory language. Since 
then, the FAA and the part 23 industry have worked together to develop 
common part 23 airplane certification requirements for this rulemaking. 
In 2011, with the Part 23 CPS as a foundation, the FAA formed the Part 
23 Reorganization ARC. The ARC consisted of large and small entity 
domestic and international businesses. We contacted the part 23 
airplane manufacturers, the ARC, and GAMA for specific cost estimates 
for each section change for the rule and they all believe that this 
proposed rule would have a minimal cost impact on their operations and 
in many cases, would have significant cost savings by streamlining the 
part 23 type certification process. Many of the ARC members 
collaborated and provided a joint cost estimate for the proposed rule.
    The ARC has informed us that the proposed rule would save the 
manufacturers design time for the certification of part 23 airplanes by 
reducing the number of exemptions, equivalent level of safety findings 
and special conditions required to incorporate new and future 
technology into their new airplane certifications. The proposed rule 
would also require manuals to be updated and database development. We 
expect these updates to be minimal and request commen on these 
anticipated costs and overall reduction in paperwork burden.
    The ARC has also informed us that every other section of this 
proposed rule would be cost-neutral since the majority of the 
prescriptive requirements in part 23 would be moved from part 23. The 
FAA expects that these current requirements would form the basis for 
consensus standards that would be used as a means of compliance to the 
proposed performance based regulations.
    The FAA expects this proposed rule could have a positive economic 
impact to small entities because it would enable new businesses to 
produce new part 23 type certificated airplanes while maintaining a 
safe operating environment in the NAS. This proposal is based on the 
ARC's recommendations and would allow for the use of consensus 
standards that have been developed in partnership with industry. 
Therefore, the FAA believes that this proposed rule could have a 
positive significant economic impact on a substantial number of 
entities.
7. Alternative Analysis
a. Alternative 1
    The FAA would continue to issue special conditions, exemptions, and 
equivalent level of safety findings to certificate part 23 airplanes. 
As this approach would not follow congressional direction, we choose 
not to continue with the status quo.
b. Alternative 2
    The FAA would continue to enforce the current regulations that 
affect stall and controllability. The FAA rejected this alternative 
because the accident rate for part 23 airplanes identified a safety 
issue that had to be addressed.
c. Alternative 3
    The FAA notes that a multi-engine part 23 aircraft manufacturer 
could decide it wants to comply with Sec.  23.200(b) by making the 
airplane capable of climbing after a critical loss by installing larger 
engines. But this is a very expensive alternative that would raise 
certification costs and operating costs and we believe that part 23 
aircraft manufacturers would not make the airplane capable of climbing 
after a critical loss by installing larger engines.
    The FAA solicits comments regarding this determination.

C. International Trade Impact Assessment

    The Trade Agreements Act of 1979 (Pub. L. 96-39), as amended by the 
Uruguay Round Agreements Act (Pub. L. 103-465), prohibits Federal 
agencies from establishing standards or engaging in related activities 
that create unnecessary obstacles to the foreign commerce of the United 
States. Pursuant to these Acts, the establishment of standards is not 
considered an unnecessary obstacle to the foreign commerce of the 
United States, so long as the standard has a legitimate domestic 
objective, such as the protection of safety, and does not operate in a 
manner that excludes imports that meet this objective. The statute also 
requires consideration of international standards and, where 
appropriate, that they be the basis for U.S. standards. The FAA has 
assessed the potential effect of this proposed rule and determined that 
the standards are necessary for aviation safety and would not create 
unnecessary obstacles to the foreign commerce of the United States.

D. Unfunded Mandates Assessment

    Title II of the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-
4) requires each Federal agency to prepare a written statement 
assessing the effects of any Federal mandate in a proposed or final 
agency rule that may result in an expenditure of $100 million or more 
(in 1995 dollars) in any one year by State, local, and tribal 
governments, in the aggregate, or by the private sector; such a mandate 
is deemed to be a ``significant regulatory action.'' The FAA currently 
uses an inflation-adjusted value of $155.0 million in lieu of $100 
million. This proposed rule does not contain such a mandate; therefore, 
the requirements of Title II of the Act do not apply.

E. Paperwork Reduction Act

    The Paperwork Reduction Act of 1995 (44 U.S.C. 3507(d)) requires 
that the FAA consider the impact of paperwork and other information 
collection burdens imposed on the public. The information requirements 
for aircraft certification are covered by existing OMB No. 2120-0018. 
Burdens associated with special conditions,

[[Page 13501]]

ELOS, and exemptions are not quantified in this collection because the 
need to seek relief under one of these options is dependent on each 
applicant and is difficult to quantify. It is expected that this 
rulemaking would reduce the number of special conditions, ELOS, and 
exemptions filed, thus reducing paperwork and processing time for both 
the FAA and industry. It would also maintain the fundamental safety 
requirements from the current part 23 regulations but allow more 
flexibility in airplane designs, faster adoption of safety enhancing 
technology, and reduce the regulatory cost burden. To estimate savings 
driven by this change, the FAA counted the special conditions, ELOS, 
and exemption applications submitted to the FAA for part 23 aircraft 
between 2012 and 2013 and divided the number by two years for an 
average of 47 applications per year.\29\ The ARC report offered a 
similar average of 37 applications per year.\30\ Additionally, the FAA 
counted the number of pages per application for all 47 applications to 
obtain an average number of pages per application. For special 
conditions, there were approximately 21 pages, 16 pages for an 
exemption, and 15 pages per ELOS application. The FAA assumes that the 
applicant and each FAA office that reviews the application spend 8 
hours on research, coordination, and review per page. The ARC also 
noted ``an ELOS finding or exemption can take the FAA between 4 to 12 
months to develop and approve. The applicant spends roughly the same 
amount of time as the FAA in proposing what they need and responding to 
FAA questions for SC, exemption, or ELOS.'' \31\
---------------------------------------------------------------------------

    \29\ https://my.faa.gov/org/linebusiness/avs/offices/air/tools/cert.html.
    \30\ A report from the 14 CFR part 23 Reorganization Aviation 
Rulemaking Committee to the Federal Aviation Administration; 
Recommendation for increasing the safety of small general aviation 
airplanes certificated to 14 CFR part 23, June 5, 2013, Table 7.1--
Special Conditions, Exemptions, Equivalent Safety Findings, Page 55.
    \31\ Ibid., 54.
---------------------------------------------------------------------------

    The number of applications is multiplied by the number of pages and 
by the hourly wage for the applicant and different FAA offices to 
account for the cost to the FAA and the applicant. The estimated hourly 
wage is $74.10 for a Small Airplane Directorate employee,\32\ $50.75 
for an Aircraft Certificate Office employee,\33\ and $60.58 for an 
engineer \34\ employed by the applicant. Annual cost equals the sum of 
the associated costs of special conditions, exemptions, plus equivalent 
level of safety. Yearly cost totals roughly $502,469 for the Small 
Airplane Directorate, $344,172 for Aircraft Certificate Offices, and 
$410,823 for the applicants. Tables 1, 2, and 3 show cost by office and 
applicant as well as by special condition, exemption, and ELOS.
---------------------------------------------------------------------------

    \32\ 2014 FAA Bay Band, Average K Band Salary (Rest of the U.S.) 
plus wage multiplier for benefits https://employees.faa.gov/org/staffoffices/ahr/program_policies/policy_guidance/hr_policies/hrpm/comp/comp_ref/2014payadjustment/.
    \33\ 2014 FAA Bay Band, Average I Band Salary (Rest of the U.S.) 
plus wage multiplier for benefits https://employees.faa.gov/org/staffoffices/ahr/program_policies/policy_guidance/hr_policies/hrpm/comp/comp_ref/2014payadjustment/.
    \34\ National Occupational Employment and Wage Estimates United 
States, May 2014; Aerospace Engineer mean hourly wage, NAIC code 17-
2011 plus wage multiplier for benefits http://www.bls.gov/oes/current/oes_nat.htm#17-0000. A more detailed discussion is provided 
in the ``Costs'' section below.

                                                     Table 1--Savings From Special Conditions (SC) *
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                               Average number    Average             FAA SAD                   FAA ACO                  Applicant
               Part 23 Section                  of SC (2012-    number of  -----------------------------------------------------------------------------
                                                    2013)         pages      Man-hours     Savings     Man-hours     Savings     Man-hours     Savings
--------------------------------------------------------------------------------------------------------------------------------------------------------
143..........................................             0.5         20.8           83       $6,165           83       $4,223           83       $5,040
171..........................................             0.5         20.8           83        6,165           83        4,223           83        5,040
173..........................................             0.5         20.8           83        6,165           83        4,223           83        5,040
175..........................................             0.5         20.8           83        6,165           83        4,223           83        5,040
177..........................................             0.5         20.8           83        6,165           83        4,223           83        5,040
251..........................................             0.5         20.8           83        6,165           83        4,223           83        5,040
361..........................................               1         20.8          166       12,330          166        8,445          166       10,081
562..........................................               1         20.8          166       12,330          166        8,445          166       10,081
572..........................................             0.5         20.8           83        6,165           83        4,223           83        5,040
573..........................................             0.5         20.8           83        6,165           83        4,223           83        5,040
574..........................................             0.5         20.8           83        6,165           83        4,223           83        5,040
613..........................................             0.5         20.8           83        6,165           83        4,223           83        5,040
627..........................................             0.5         20.8           83        6,165           83        4,223           83        5,040
629..........................................             1.5         20.8          250       18,495          250       12,668          250       15,121
901..........................................               1         20.8          166       12,330          166        8,445          166       10,081
939..........................................             0.5         20.8           83        6,165           83        4,223           83        5,040
951..........................................               1         20.8          166       12,330          166        8,445          166       10,081
961..........................................               1         20.8          166       12,330          166        8,445          166       10,081
973..........................................               1         20.8          166       12,330          166        8,445          166       10,081
977..........................................             1.5         20.8          250       18,495          250       12,668          250       15,121
1141.........................................             0.5         20.8           83        6,165           83        4,223           83        5,040
1301.........................................             0.5         20.8           83        6,165           83        4,223           83        5,040
1305.........................................               1         20.8          166       12,330          166        8,445          166       10,081
1308.........................................             0.5         20.8           83        6,165           83        4,223           83        5,040
1309.........................................               1         20.8          166       12,330          166        8,445          166       10,081
1329.........................................             0.5         20.8           83        6,165           83        4,223           83        5,040
1337.........................................             0.5         20.8           83        6,165           83        4,223           83        5,040
1521.........................................               1         20.8          166       12,330          166        8,445          166       10,081
1557.........................................               1         20.8          166       12,330          166        8,445          166       10,081
3Pt Restraint with Airbag....................             0.5         20.8           83        6,165           83        4,223           83        5,040
Inflatable Restraint.........................             0.5         20.8           83        6,165           83        4,223           83        5,040
Electronic Engine Controls...................             0.5         20.8           83        6,165           83        4,223           83        5,040

[[Page 13502]]

 
Fuel Jettisoning.............................             0.5         20.8           83        6,165           83        4,223           83        5,040
Load Alleviation System......................             0.5         20.8           83        6,165           83        4,223           83        5,040
Side Facing Seat with Airbag.................             0.5         20.8           83        6,165           83        4,223           83        5,040
                                              ----------------------------------------------------------------------------------------------------------
    Totals...................................            24.5          728         4077      302,080         4077      206,914         4077      246,983
--------------------------------------------------------------------------------------------------------------------------------------------------------
* These numbers are subject to rounding error.


                                                           Table 2--Savings From Exemptions *
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                               Average number    Average             FAA SAD                   FAA ACO                  Applicant
               Part 23 Section                   exemptions     number of  -----------------------------------------------------------------------------
                                                 (2012-2013)      pages      Man-hours     Savings     Man-hours     Savings     Man-hours     Savings
--------------------------------------------------------------------------------------------------------------------------------------------------------
1359.........................................             0.5         15.6         62.4       $4,624           62       $3,167           62       $3,780
1549.........................................             0.5         15.6         62.4        4,624           62        3,167           62        3,780
177..........................................             0.5         15.6         62.4        4,624           62        3,167           62        3,780
49...........................................               1         15.6        124.8        9,247          125        6,334          125        7,561
562..........................................               1         15.6        124.8        9,247          125        6,334          125        7,561
1419.........................................             0.5         15.6         62.4        4,624           62        3,167           62        3,780
                                              ----------------------------------------------------------------------------------------------------------
    Totals...................................               4           94          499       36,989          499       25,336          499       30,243
--------------------------------------------------------------------------------------------------------------------------------------------------------
* These numbers are subject to rounding error.


                                                Table 3--Savings From Equivalent Level of Safety (ELOS) *
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                               Average number    Average             FAA SAD                   FAA ACO                  Applicant
               Part 23 Section                   ELOS (2012-    number of  -----------------------------------------------------------------------------
                                                    2013)         pages      Man-hours     Savings     Man-hours     Savings      Savings     Man-hours
--------------------------------------------------------------------------------------------------------------------------------------------------------
145..........................................               1         14.9        119.2       $8,832          119       $6,050          119       $7,221
207..........................................               1         14.9        119.2        8,832          119        6,050          119        7,221
672..........................................             0.5         14.9         59.6        4,416           60        3,025           60        3,611
777..........................................             1.5         14.9        178.8       13,249          179        9,075          179       10,832
779..........................................             0.5         14.9         59.6        4,416           60        3,025           60        3,611
781..........................................             1.5         14.9        178.8       13,249          179        9,075          179       10,832
807..........................................             0.5         14.9         59.6        4,416           60        3,025           60        3,611
815..........................................             0.5         14.9         59.6        4,416           60        3,025           60        3,611
841..........................................               1         14.9        119.2        8,832          119        6,050          119        7,221
973..........................................             0.5         14.9         59.6        4,416           60        3,025           60        3,611
1092.........................................             0.5         14.9         59.6        4,416           60        3,025           60        3,611
1145.........................................               1         14.9        119.2        8,832          119        6,050          119        7,221
1305.........................................             1.5         14.9        178.8       13,249          179        9,075          179       10,832
1311.........................................             0.5         14.9         59.6        4,416           60        3,025           60        3,611
1353.........................................             0.5         14.9         59.6        4,416           60        3,025           60        3,611
1357.........................................             0.5         14.9         59.6        4,416           60        3,025           60        3,611
1397.........................................             0.5         14.9         59.6        4,416           60        3,025           60        3,611
1401.........................................             0.5         14.9         59.6        4,416           60        3,025           60        3,611
1419.........................................             0.5         14.9         59.6        4,416           60        3,025           60        3,611
1443.........................................             0.5         14.9         59.6        4,416           60        3,025           60        3,611
1505.........................................             0.5         14.9         59.6        4,416           60        3,025           60        3,611
1545.........................................             0.5         14.9         59.6        4,416           60        3,025           60        3,611
1549.........................................             2.5         14.9          298       22,081          298       15,125          298       18,054
                                              ----------------------------------------------------------------------------------------------------------
    Totals...................................              19          343         2205      163,400         2205      111,923         2205      133,597
--------------------------------------------------------------------------------------------------------------------------------------------------------
* These numbers are subject to rounding error.

    Using these yearly cost estimates, over 20 years $25.1 million in 
man-hours would be spent on applying for and processing special 
conditions, exemptions, and ELOS. However under the proposed rule, the 
FAA believes that the need to demonstrate compliance through special 
conditions, exemptions, or ELOS would largely be eliminated. Instead 
new products will simply need to demonstrate compliance by following 
consensus standards acceptable to the Administrator, or by submitting 
their own novel demonstrations of compliance. As a conservative 
estimate, the FAA estimates that special conditions, exemptions, and 
ELOS would be reduced by half for a savings to the FAA and applicant of 
roughly $12.6 million ($5.8 million present value). Savings by year is 
shown in the chart below. The FAA asks for comment regarding the amount 
of reduction in the alternative means of compliance.

[[Page 13503]]

    In addition to this savings, there would also be additional 
paperwork burden associated with proposed Sec.  23.200. As proposed, 
this provision could result in a change to a limitation or a 
performance number in the flight manual, which would reqire an update 
to the training courseware or flight manual. Industry believes that 
this proposed change could cost from $100,000 to $150,000. Therefore, 
the FAA uses $125,000 (($100,000 + $150,000)/2) as an average cost for 
this proposed change.
    There would also be additional paperwork associated with this 
requirement that is not part of the costs discussed above. The FAA 
estimates the paperwork costs for these proposed provisions by 
multiplying the number of hours the FAA estimates for each page of 
paperwork, by the number of pages for the training courseware, or 
flight manual, by the hourly rate of the person responsible for the 
update. The Small Aircraft Directorate of the FAA provided average 
hourly times and the number of additional pages of paperwork the 
proposal would add. The FAA estimates that this section would add a 
total of four pages to the training courseware and flight manual. The 
FAA also estimates that it would take a part 23 certification engineer 
eight hours to complete the one page required for each new type 
certification. The eight hours to complete a page includes the 
research, coordination, and review each document requires. Therefore, 
the FAA estimates the total paperwork costs for proposed 
controllability section would be about $1,939 (8 hours * 4 pages * 
$60.58 per hour) in 2014 dollars.
    The FAA is expecting part 23 airplane manufacturers to update their 
engineering procedures manuals to reflect the changes from this 
proposed rulemaking. However, most of the engineering procedures 
manuals are not written around the requirements of part 23, but around 
the requirements of part 21. Since the part 23 changes would have 
minimal impact on the part 21 requirements, there should be little 
change in the engineering procedures manuals. Conversations with 
industry indicate that there may need to be some changes to the 
engineering manuals to describe how the accepted means of compliance 
must be related to the regulations. Depending on the complexity of each 
company's manual, industry estimates that these changes could run from 
about $50,000 up to $200,000. This would be a one-time cost per new 
type certification.
    Since the FAA is unable to determine the complexity of each 
company's manual, we assume that the manufacturers of the two new part 
23 reciprocating engine airplane type certifications, discussed in the 
``Fleet Discussion'' section of the regulatory impact analysis, would 
spend $50,000 to make the changes to the engineering manual. We also 
assume that the one new part 23 turboprop airplane certification and 
the two new part 23 turbojet airplane certifications, discussed in the 
``Fleet Discussion'' section, would use the more complex and costly 
approach of $200,000.
    The FAA notes that either the simple approach or the more complex 
approach to updating the manuals could also either take place in-house 
or could be contracted out to a consultant.
    Table 4 shows the total costs for the proposed changes to the 
controllability section.

                            Table 4--Estimate Costs for Updating Engineering Manuals
                                                    [2014 $]
----------------------------------------------------------------------------------------------------------------
                                                               Number of
                                                               estimated      Simple      Complex
                          Airplane                             new type      approach     approach      Total
                                                             certificates
----------------------------------------------------------------------------------------------------------------
Recip......................................................             2      $50,000           $0     $100,000
Turboprop..................................................             1            0      200,000      200,000
Turbojet...................................................             2            0      200,000      400,000
                                                            ----------------------------------------------------
    Total..................................................  ............  ...........  ...........      700,000
----------------------------------------------------------------------------------------------------------------
* These numbers are subject to rounding error.

F. International Compatibility and Cooperation

    In keeping with U.S. obligations under the Convention on 
International Civil Aviation, it is FAA policy to conform to 
International Civil Aviation Organization (ICAO) Standards and 
Recommended Practices to the maximum extent practicable. The FAA has 
reviewed the corresponding ICAO Standards and Recommended Practices and 
has identified the following differences with these proposed 
regulations. The ICAO Standards for small airplanes use weight and 
propulsion to differentiate between some requirements. The proposed 
regulations use certification levels and performance to differentiate 
between some requirements. Furthermore, part 23 will still allow the 
certification of airplanes up to 19,000 pounds. If this proposal is 
adopted, the FAA intends to file these differences with ICAO. Executive 
Order (EO) 13609, Promoting International Regulatory Cooperation, (77 
FR 26413, May 4, 2012) promotes international regulatory cooperation to 
meet shared challenges involving health, safety, labor, security, 
environmental, and other issues and reduce, eliminate, or prevent 
unnecessary differences in regulatory requirements. The FAA has 
analyzed this action under the policy and agency responsibilities of 
Executive Order 13609, Promoting International Regulatory Cooperation. 
The agency has determined that this action would eliminate differences 
between U.S. aviation standards and those of other CAAs by aligning the 
revised part 23 standards with the new CS-23 standards that are being 
developed concurrently by EASA. Several other CAAs are participating in 
this effort and intend to either adopt the new part 23 or CS-23 
regulations or revise their airworthiness standards to align with these 
new regulations.
    The Part 23 Reorganization ARC included participants from several 
foreign CAAs and international members from almost every GA 
manufacturer of both airplanes and avionics. It also included several 
Light-Sport Aircraft manufacturers who are interested in certificating 
their products using the airworthiness standards contained in part 23. 
The rulemaking and means of compliance documents are international 
efforts. Authorities from Europe, Canada, Brazil, China, and New 
Zealand all are working to produce similar rules. These rules, while 
not identical, are intended to allow the use

[[Page 13504]]

of the same set of industry developed means of compliance. Industry has 
told that FAA that it is very costly to address the differences that 
some contrived means of compliance imposes. If there is substantial 
agreement between the major CAAs to use the same industry means of 
compliance document, then U.S. manufactures expect a significant saving 
for exporting their products.
    Furthermore, this project is a harmonization project between the 
FAA and EASA.
    EASA has worked a parallel rulemaking program for CS-23. The FAA 
provided comments to the EASA A-NPA The EASA and other authorities will 
have an opportunity to comment on this NPRM when it is published. These 
efforts will allow the FAA, EASA and other authorities to work toward a 
harmonized set of regulations when the final rules are published.

G. Environmental Analysis

    FAA Order 1050.1F identifies FAA actions that are categorically 
excluded from preparation of an environmental assessment or 
environmental impact statement under the National Environmental Policy 
Act in the absence of extraordinary circumstances. The FAA has 
determined this rulemaking action qualifies for the categorical 
exclusion identified in paragraph 5-6.6 and involves no extraordinary 
circumstances.

H. Regulations Affecting Intrastate Aviation in Alaska

    Section 1205 of the FAA Reauthorization Act of 1996 (110 Stat. 
3213) requires the Administrator, when modifying 14 CFR regulations in 
a manner affecting intrastate aviation in Alaska, to consider the 
extent to which Alaska is not served by transportation modes other than 
aviation, and to establish appropriate regulatory distinctions. Because 
this proposed rule would apply to GA airworthiness standards, it could, 
if adopted, affect intrastate aviation in Alaska. The FAA, therefore, 
specifically requests comments on whether there is justification for 
applying the proposed rule differently in intrastate operations in 
Alaska.

VIII. Executive Order Determination

A. Executive Order 13132, Federalism

    The FAA has analyzed this proposed rule under the principles and 
criteria of Executive Order 13132, Federalism. The agency has 
determined that this action would not have a substantial direct effect 
on the States, or the relationship between the Federal Government and 
the States, or on the distribution of power and responsibilities among 
the various levels of government, and, therefore, would not have 
Federalism implications.

B. Executive Order 13211, Regulations That Significantly Affect Energy 
Supply, Distribution, or Use

    The FAA analyzed this proposed rule under Executive Order 13211, 
Actions Concerning Regulations that Significantly Affect Energy Supply, 
Distribution, or Use (May 18, 2001). The agency has determined that it 
would not be a ``significant energy'' action under the executive order 
and would not be likely to have a significant adverse effect on the 
supply, distribution, or use of energy.

IX. Additional Information

A. Comments Invited

    The FAA invites interested persons to participate in this 
rulemaking by submitting written comments, data, or views. The agency 
also invites comments relating to the economic, environmental, energy, 
or federalism impacts that might result from adopting the proposals in 
this document. The most helpful comments reference a specific portion 
of the proposal, explain the reason for any recommended change, and 
include supporting data. To ensure the docket does not contain 
duplicate comments, commenters should send only one copy of written 
comments, or if comments are filed electronically, commenters should 
submit only one time.
    The FAA will file in the docket all comments it receives, as well 
as a report summarizing each substantive public contact with FAA 
personnel concerning this proposed rulemaking. Before acting on this 
proposal, the FAA will consider all comments it receives on or before 
the closing date for comments. The FAA will consider comments filed 
after the comment period has closed if it is possible to do so without 
incurring expense or delay. The agency may change this proposal in 
light of the comments it receives.
    Proprietary or Confidential Business Information: Commenters should 
not file proprietary or confidential business information in the 
docket. Such information must be sent or delivered directly to the 
person identified in the FOR FURTHER INFORMATION CONTACT section of 
this document, and marked as proprietary or confidential. If submitting 
information on a disk or CD-ROM, mark the outside of the disk or CD-
ROM, and identify electronically within the disk or CD-ROM the specific 
information that is proprietary or confidential.
    Under 14 CFR 11.35(b), if the FAA is aware of proprietary 
information filed with a comment, the agency does not place it in the 
docket. It is held in a separate file to which the public does not have 
access, and the FAA places a note in the docket that it has received 
it. If the FAA receives a request to examine or copy this information, 
it treats it as any other request under the Freedom of Information Act 
(5 U.S.C. 552). The FAA processes such a request under Department of 
Transportation procedures found in 49 CFR part 7.

B. Availability of Rulemaking Documents

    An electronic copy of rulemaking documents may be obtained from the 
Internet by--
    1. Searching the Federal eRulemaking Portal (http://www.regulations.gov);
    2. Visiting the FAA's Regulations and Policies Web page at http://www.faa.gov/regulations_policies or
    3. Accessing the Government Printing Office's Web page at http://www.gpo.gov/fdsys/.
    Copies may also be obtained by sending a request to the Federal 
Aviation Administration, Office of Rulemaking, ARM-1, 800 Independence 
Avenue SW., Washington, DC 20591, or by calling (202) 267-9680. 
Commenters must identify the docket or notice number of this 
rulemaking.
    All documents the FAA considered in developing this proposed rule, 
including economic analyses and technical reports, may be accessed from 
the Internet through the Federal eRulemaking Portal referenced in item 
(1) above.

Appendix 1 to the Preamble--Current to Proposed Regulations Cross-
Reference Table

    The below cross-reference table is intended to permit easy access 
from proposed to current regulations. The preamble is organized 
topical, section-by-section, proposed to current regulations. This 
table should assist the reader in following the section discussions 
contained in the preamble.

[[Page 13505]]



----------------------------------------------------------------------------------------------------------------
          Current section                      Title               Proposed section          Proposed title
----------------------------------------------------------------------------------------------------------------
                                               Subpart A--General
----------------------------------------------------------------------------------------------------------------
23.1..............................  Applicability.............  23.1.................  Applicability.
23.2..............................  Special retroactive         .....................  --Deleted--
                                     requirements.
23.3..............................  Airplane categories.......  23.5.................  Certification of normal
                                                                                        category airplanes.
                                    ..........................  23.10................  Accepted means of
                                                                                        compliance.
----------------------------------------------------------------------------------------------------------------
                                                Subpart B--Flight
----------------------------------------------------------------------------------------------------------------
23.21.............................  Proof of compliance.......  23.100...............  Weight and center of
                                                                                        gravity.
23.23.............................  Load distribution limits..  23.100...............  Weight and center of
                                                                                        gravity.
23.25.............................  Weight limits.............  23.100...............  Weight and center of
                                                                                        gravity.
23.29.............................  Empty weight and            23.100...............  Weight and center of
                                     corresponding center of                            gravity.
                                     gravity.
23.31.............................  Removable ballast.........  23.100...............  Weight and center of
                                                                                        gravity.
23.33.............................  Propeller speed and pitch   23.900...............  Powerplant installation.
                                     limits.
23.45.............................  Performance--General......  23.105...............  Performance.
23.49.............................  Stalling speed............  23.110...............  Stall Speed.
23.51.............................  Takeoff speeds............  23.115...............  Takeoff performance.
23.53.............................  Takeoff performance.......  23.115...............  Takeoff performance.
23.55.............................  Accelerate-stop distance..  23.115...............  Takeoff performance.
23.57.............................  Takeoff path..............  23.115...............  Takeoff performance.
23.59.............................  Takeoff distance and        23.115...............  Takeoff performance.
                                     takeoff run.
23.61.............................  Takeoff flight path.......  23.115...............  Takeoff performance.
23.63.............................  Climb: General............  23.120...............  Climb.
23.65.............................  Climb: All engines          23.120...............  Climb.
                                     operating.
23.66.............................  Takeoff climb: one engine   23.125...............  Climb.
                                     inoperative.
23.67.............................  Climb: One engine           23.120...............  Climb.
                                     inoperative.
23.69.............................  Enroute climb/descent.....  23.125...............  Climb.
23.71.............................  Glide: single engine        23.125...............  Climb.
                                     airplanes.
23.73.............................  Reference landing approach  23.130...............  Landing.
                                     speed.
23.75.............................  Landing distance..........  23.130...............  Landing.
23.77.............................  Balked landing............  23.120...............  Climb.
23.141............................  Flight Characteristics--    23.200...............  Controllability.
                                     General.
23.143............................  Controllability and         23.200...............  Controllability.
                                     Maneuverability--General.
23.145............................  Longitudinal control......  23.200...............  Controllability.
23.147............................  Directional and lateral     23.200...............  Controllability.
                                     control.
23.149............................  Minimum control speed.....  23.200...............  Controllability.
23.151............................  Acrobatic maneuvers.......  23.200...............  Controllability.
23.153............................  Control during landings...  23.200...............  Controllability.
23.155............................  Elevator control force in   23.200...............  Controllability.
                                     maneuvers.
23.157............................  Rate of roll..............  23.200...............  Controllability.
23.161............................  Trim......................  23.205...............  Trim.
23.171............................  Stability--General........  23.210...............  Stability.
23.173............................  Static longitudinal         23.210...............  Stability.
                                     stability.
23.175............................  Demonstration of static     23.210...............  Stability.
                                     longitudinal stability.
23.177............................  Static directional and      23.210...............  Stability.
                                     lateral stability.
23.179............................  Instrument stick force      23.210...............  Stability.
                                     measurements.
23.181............................  Dynamic stability.........  23.210...............  Stability.
23.201............................  Wings level stall.........  23.215...............  Stall characteristics,
                                                                                        stall warning, and
                                                                                        spins.
23.203............................  Turning Flight and          23.215...............  Stall characteristics,
                                     accelerated turning                                stall warning, and
                                     stalls.                                            spins.
23.207............................  Stall Warning.............  23.215...............  Stall characteristics,
                                                                                        stall warning, and
                                                                                        spins.
23.221............................  Spinning..................  23.215...............  Stall characteristics,
                                                                                        stall warning, and
                                                                                        spins.
23.231............................  Longitudinal stability and  23.220...............  Ground handling.
                                     control.
23.233............................  Directional stability and   23.220...............  Ground handling.
                                     control.
23.235............................  Operation on unpaved        23.220...............  Ground handling.
                                     surfaces.
23.237............................  Operation on water........  23.220...............  Ground handling.
23.239............................  Spray characteristics.....  23.220...............  Ground handling.
23.251............................  Vibration and buffeting...  23.225...............  Vibration, buffeting, and
                                                                                        high-speed
                                                                                        characteristics.
23.253............................  High speed characteristics  23.225...............  Vibration, buffeting, and
                                                                                        high-speed
                                                                                        characteristics.
23.255............................  Out of trim                 23.225...............  Vibration, buffeting, and
                                     characteristics.                                   high-speed
                                                                                        characteristics.
                                                                23.230...............  Performance and flight
                                                                                        characteristics
                                                                                        requirements for flight
                                                                                        in icing conditions.
----------------------------------------------------------------------------------------------------------------

[[Page 13506]]

 
                                              Subpart C--Structure
----------------------------------------------------------------------------------------------------------------
23.301............................  Loads.....................  23.310, 23.330.......  Structural design loads,
                                                                                        Limit and ultimate
                                                                                        loads.
(a)...............................  ..........................  23.330...............  Limit and ultimate loads.
(b)...............................  ..........................  23.310...............  Structural design loads.
(c)...............................  ..........................  23.310...............  Structural design loads.
(d)...............................  ..........................  23.310...............  Structural design loads.
23.302............................  Canard or tandem wing       23.310...............  Structural design loads.
                                     configurations.
23.303............................  Factors of safety.........  23.330...............  Limit and ultimate loads.
23.305............................  Strength and deformation..  23.400...............  Structural strength.
                                                                23.305...............  Interaction of systems
                                                                                        and structures.
23.307............................  Proof of structure........  23.400...............  Structure strength.
23.321............................  Flight Loads--General.....  23.310...............  Structural design loads.
(a)...............................  ..........................  23.310...............  Structural design loads.
(b)...............................  ..........................  23.300...............  Structural design
                                                                                        envelope.
(c)...............................  ..........................  23.300...............  Structural design
                                                                                        envelope.
23.331............................  Symmetrical flight          23.310...............  Structural design loads.
                                     conditions.
23.333............................  Flight envelope...........  23.300...............  Structural design
                                                                                        envelope.
(a)...............................  ..........................  23.300...............  Structural design
                                                                                        envelope.
(b)...............................  ..........................  23.300...............  Structural design
                                                                                        envelope.
(c)...............................  ..........................  23.315...............  Flight load conditions.
(d)...............................  ..........................  23.300...............  Structural design
                                                                                        envelope.
23.335............................  Design airspeeds..........  23.300...............  Structural design
                                                                                        envelope.
23.337............................  Limit maneuvering load      23.300...............  Flight load conditions.
                                     factors.
(a)...............................  ..........................  23.300...............  Structural design
                                                                                        envelope.
(b)...............................  ..........................  23.300...............  Structural design
                                                                                        envelope.
(c)...............................  ..........................  Means of Compliance..
23.341............................  Gust load factors.........  23.315...............  Flight load conditions.
23.343............................  Design fuel loads.........  23.300...............  Structural design
                                                                                        envelope.
(a)...............................  ..........................  23.300...............  Structural design
                                                                                        envelope.
(b)...............................  ..........................  23.300...............  Structural design
                                                                                        envelope.
(c)...............................  ..........................  Means of Compliance..
23.345............................  High lift devices.........  23.325...............  Component loading
                                                                                        conditions.
23.347............................  Unsymmetrical flight loads  23.315...............  Flight load conditions.
23.349............................  Rolling conditions........  23.315...............  Flight load conditions.
23.351............................  Yawing conditions.........  23.315...............  Flight load conditions.
23.361............................  Engine torque.............  23.325...............  Component loading
                                                                                        conditions.
23.363............................  Side load on engine mount.  23.325...............  Component loading
                                                                                        conditions.
23.365............................  Pressurized cabin loads...  23.325...............  Flight load conditions.
(e)...............................  ..........................  23.405...............  Structural durability.
23.367............................  Unsymmetrical loads due to  23.315...............  Flight load conditions.
                                     engine failure.
23.369............................  Rear lift truss...........  Means of Compliance..
23.371............................  Gyroscopic and aerodynamic  23.325...............  Component loading
                                     loads.                                             conditions.
23.373............................  Speed control devices.....  23.325...............  Component loading
                                                                                        conditions.
23.391............................  Control surface loads.....  23.325...............  Component loading
                                                                                        conditions.
23.393............................  Loads parallel to hinge     23.325...............  Component loading
                                     line.                                              conditions.
23.395............................  Control system loads......  23.325...............  Component loading
                                                                                        conditions.
23.397............................  Limit control forces and    23.325...............  Component loading
                                     torques.                                           conditions.
23.399............................  Dual control system.......  23.325...............  Component loading
                                                                                        conditions.
23.405............................  Secondary control system..  23.325...............  Component loading
                                                                                        conditions.
23.407............................  Trim tab effects..........  23.325...............  Component loading
                                                                                        conditions.
23.409............................  Tabs......................  23.325...............  Component loading
                                                                                        conditions.
23.415............................  Ground gust conditions....  23.325...............  Component loading
                                                                                        conditions.
23.421............................  Balancing loads...........  Means of Compliance..
23.423............................  Maneuvering loads.........  23.315...............  Flight load conditions.
23.425............................  Gust loads................  23.315...............  Flight load conditions.
23.427............................  Unsymmetrical loads due to  23.315...............  Flight load conditions.
                                     engine failure.
23.441............................  Maneuvering loads.........  23.315...............  Flight load conditions.
23.443............................  Gust loads................  23.315...............  Flight load conditions.
23.445............................  Outboard fins or winglets.  Means of Compliance..
23.455............................  Ailerons..................  23.325...............  Component loading
                                                                                        conditions.
23.459............................  Special devices...........  23.325...............  Component loading
                                                                                        conditions.
23.471............................  Ground Loads--General.....  23.320...............  Ground and water load
                                                                                        conditions.
23.473............................  Ground load conditions and  23.320...............  Ground and water load
                                     assumptions.                                       conditions.
23.477............................  Landing gear arrangement..  23.320...............  Ground and water load
                                                                                        conditions.
23.479............................  Level landing conditions..  23.320...............  Ground and water load
                                                                                        conditions.
23.481............................  Tail down landing           23.320...............  Ground and water load
                                     conditions.                                        conditions.
23.483............................  One-wheel landing           23.320...............  Ground and water load
                                     conditions.                                        conditions.
23.485............................  Side load conditions......  23.320...............  Ground and water load
                                                                                        conditions.
23.493............................  Braked roll conditions....  23.320...............  Ground and water load
                                                                                        conditions.
23.497............................  Supplementary conditions    23.320...............  Ground and water load
                                     for tail wheels.                                   conditions.
23.499............................  Supplementary conditions    23.320...............  Ground and water load
                                     for nose wheels.                                   conditions.
23.505............................  Supplementary conditions    23.320...............  Ground and water load
                                     for skiplanes.                                     conditions.

[[Page 13507]]

 
23.507............................  Jacking loads.............  23.320...............  Ground and water load
                                                                                        conditions.
23.509............................  Towing loads..............  23.320...............  Ground and water load
                                                                                        conditions.
23.511............................  Ground load: unsymmetrical  23.320...............  Ground and water load
                                     loads on multiple-wheel                            conditions.
                                     units.
23.521............................  Water load conditions.....  23.320...............  Ground and water load
                                                                                        conditions.
23.523............................  Design weights and center   23.320...............  Ground and water load
                                     of gravity positions.                              conditions.
23.525............................  Application of loads......  23.320...............  Ground and water load
                                                                                        conditions.
23.527............................  Hull and main float load    23.320...............  Ground and water load
                                     factors.                                           conditions.
23.529............................  Hull and main float         23.320...............  Ground and water load
                                     landing conditions.                                conditions.
23.531............................  Hull and main float         23.320...............  Ground and water load
                                     takeoff conditions.                                conditions.
23.533............................  Hull and main float bottom  23.320...............  Ground and water load
                                     pressures.                                         conditions.
23.535............................  Auxiliary float loads.....  23.320...............  Ground and water load
                                                                                        conditions.
23.537............................  Seawing loads.............  23.320...............  Ground and water load
                                                                                        conditions.
23.561............................  Emergency Landing           23.600...............  Emergency conditions.
                                     Conditions--General.
23.562............................  Emergency landing dynamic   23.600...............  Emergency conditions.
                                     conditions.
23.571............................  Metallic pressurized cabin  23.405...............  Structural durability.
                                     structures.
23.572............................  Metallic wing, empennage,   23.405...............  Structural durability.
                                     and associated structures.
23.573............................  Damage tolerance and        23.405...............  Structural durability.
                                     fatigue evaluation of
                                     structure.
23.574............................  Metallic damage tolerance   23.405...............  Structural durability.
                                     and fatigue evaluation of
                                     commuter category
                                     airplanes.
23.575............................  Inspections and other       23.405...............  Structural durability.
                                     procedures.
----------------------------------------------------------------------------------------------------------------
                                       Subpart D--Design and Construction
----------------------------------------------------------------------------------------------------------------
23.601............................  General...................  23.500...............  Structural design.
23.603............................  Materials and workmanship.  23.500...............  Structural design.
23.605............................  Fabrication methods.......  23.510...............  Materials and processes.
23.607............................  Fasteners.................  23.505...............  Protection of structure.
23.609............................  Protection of Structure...  23.505...............  Protection of structure.
23.611............................  Accessibility.............  23.505...............  Protection of structure.
23.613............................  Material strength           23.510...............  Materials and processes.
                                     properties and design
                                     values.
23.619............................  Special factors...........  23.515...............  Special factors of
                                                                                        safety.
23.621............................  Casting factors...........  23.515...............  Special factors of
                                                                                        safety.
23.623............................  Bearing factors...........  23.515...............  Special factors of
                                                                                        safety.
23.625............................  Fitting factors...........  23.515...............  Special factors of
                                                                                        safety.
23.627............................  Fatigue strength..........  23.405...............  Structural durability.
23.629............................  Flutter...................  23.410...............  Aeroelasticity.
23.641............................  Proof of strength.........  Means of Compliance..
23.651............................  Proof of strength.........  Means of Compliance..
23.655............................  Installation..............  Means of Compliance..
23.657............................  Hinges....................  23.515...............  Special factors of
                                                                                        safety.
23.659............................  Mass balance..............  23.315...............  Flight load conditions.
23.671............................  Control Surfaces--General.
(a)...............................  ..........................  23.500...............  Structural design.
(b)...............................  ..........................  23.1305..............  Function and
                                                                                        installation.
23.672............................  Stability augmentation and  23.1305..............  Function and
                                     automatic and power-                               installation.
                                     operated systems.
23.673............................  Primary flight controls...  23.1305..............  Function and
                                                                                        installation.
23.675............................  Stops.....................  23.1305..............  Function and
                                                                                        installation.
23.677............................  Trim systems..............
(a)...............................  ..........................  23.700...............  Flight control systems.
(b)...............................  ..........................  23.700...............  Flight control systems.
(c)...............................  ..........................  23.410...............  Aeroelasticity.
(d)...............................  ..........................  23.700...............  Flight control systems.
23.679............................  Control system locks......  23.1305..............  Function and
                                                                                        installation.
23.681(a).........................  Limit load static tests...  23.325(b)............  Component loading
                                                                                        conditions.
23.681(b).........................  Limit load static tests...  23.515...............  Special factors of
                                                                                        safety.
23.683............................  Operation tests...........  23.500(d)............  Structural design.
23.685(a), (b), (c)...............  Control system details....  23.500(d)............  Structural design.
23.685(d).........................  Control system details....  23.1305..............  Function and
                                                                                        installation.
23.687............................  Spring devices............  23.410 and 23.500....  Aeroelasticity and
                                                                                        Structural design.
23.689............................  Cable systems.............
(a)...............................  ..........................  23.700...............  Flight control systems.
(b)...............................  ..........................  23.325(b), 23.500(d).  Component loading
                                                                                        conditions, Structural
                                                                                        design.
(c)...............................  ..........................  23.325(b), 23.500(d).  Component loading
                                                                                        conditions, Structural
                                                                                        design.
(d)...............................  ..........................  23.325(b), 23.500(d).  Component loading
                                                                                        conditions, Structural
                                                                                        design.

[[Page 13508]]

 
(e)...............................  ..........................  23.325(b), 23.500(d).  Component loading
                                                                                        conditions, Structural
                                                                                        design.
(f)...............................  ..........................  23.700...............  Flight control systems.
23.691............................  Artificial stall barrier
                                     system.
(a)...............................  ..........................  23.700...............  Flight control systems.
(b)...............................  ..........................  23.700...............  Flight control systems.
(c)...............................  ..........................  23.1305..............  Function and
                                                                                        installation.
(d)...............................  ..........................  23.700...............  Flight control systems.
(e)...............................  ..........................  23.700...............  Flight control systems.
(f)...............................  ..........................  23.700...............  Flight control systems.
(g)...............................  ..........................  23.1315..............  Equipment, systems and
                                                                                        Installations.
23.693............................  Joints....................  23.515...............  Special factors of
                                                                                        safety.
23.697............................  Wing flap controls........
(a)...............................  ..........................  23.700...............  Flight control systems.
(b) and (c).......................  ..........................  23.200...............  Controllability.
23.699............................  Wing flap position          23.1500..............  Flightcrew interface.
                                     indicator.
23.701............................  Flap interconnection......  Means of Compliance..
23.703............................  Takeoff warning system....
(a)...............................  ..........................  23.700...............  Flight control systems.
(b)...............................  ..........................  23.700...............  Flight control systems.
(c)...............................  ..........................  Definition...........
23.721............................  General...................  23.910...............  Powerplant installation
                                                                                        hazard assessment.
23.723............................  Shock absorption tests....  Means of Compliance..
23.725............................  Limit drop tests..........  Means of Compliance..
23.726............................  Ground load dynamic tests.  Means of Compliance..
23.727............................  Reserve energy absorption   Means of Compliance..
                                     drop tests.
23.729............................  Landing gear extension and
                                     retraction system.
(a)...............................  ..........................  23.705...............  Landing gear systems.
(b)...............................  ..........................  23.705...............  Landing gear systems.
(c)...............................  ..........................  23.705...............  Landing gear systems.
(d)...............................  ..........................  Means of Compliance..
(e)...............................  ..........................  23.705...............  Landing gear systems.
(f)...............................  ..........................  23.1315..............  Equipment, systems and
                                                                                        installation.
(g)...............................  ..........................  Means of Compliance..
23.731............................  Wheels....................  23.705...............  Landing gear systems.
23.733............................  Tires.....................
(a)...............................  ..........................  23.705...............  Landing gear systems.
(b)...............................  ..........................  Means of Compliance..
(c)...............................  ..........................  Means of Compliance..
23.735............................  Brakes....................  23.705...............
(a)...............................  ..........................  23.705...............  Landing gear systems.
(1)...............................  ..........................  Means of Compliance..
(2)...............................  ..........................  Means of Compliance..
(b)...............................  ..........................  23.705...............  Landing gear systems.
(c)...............................  ..........................  Means of Compliance..
(d)...............................  ..........................  1315.................  Equipment, systems and
                                                                                        installation.
(e)...............................  ..........................  705..................  Landing gear systems.
(1)...............................  ..........................  Means of Compliance..
(2)...............................  ..........................  Means of Compliance..
23.737............................  Skis......................  23.705...............  Landing gear systems.
23.745............................  Nose/Tail wheel steering..  23.1500..............  Flightcrew interface.
23.751............................  Main float buoyancy.......
(a)...............................  ..........................  710..................  Buoyancy for seaplanes
                                                                                        and amphibians.
(b)...............................  ..........................  Means of Compliance..
23.753............................  Main float design.........  23.320...............  Ground and water load
                                                                                        conditions.
23.755............................  Hulls.....................  23.710...............  Buoyancy for seaplanes
                                                                                        and amphibians.
23.757............................  Auxiliary floats..........  23.710...............  Buoyancy for seaplanes
                                                                                        and amphibians.
23.771............................  Pilot compartment.........
(a)...............................  ..........................  23.1500..............  Flightcrew interface.
(b)...............................  ..........................  755..................  Occupant physical
                                                                                        environment.
(c)...............................  ..........................  755..................  Occupant physical
                                                                                        environment.
23.773............................  Pilot compartment view....
(a)...............................  ..........................  1500.................  Flightcrew interface.
(b)...............................  ..........................  23.755...............  Occupant physical
                                                                                        environment.
23.775............................  Windshields and windows...
(a), (b), (c), (d)................  ..........................  23.755...............  Occupant physical
                                                                                        environment.
(e)...............................  ..........................  Means of Compliance..
(f)...............................  ..........................  23.1405..............  Flight in icing
                                                                                        conditions.
(g)...............................  ..........................  Means of Compliance..
(h)...............................  ..........................  23.755...............  Occupant physical
                                                                                        environment.
23.777............................  Cockpit controls..........  23.1500..............  Flightcrew interface.
23.779............................  Motion and effect of        23.1500..............  Flightcrew interface.
                                     cockpit controls.
23.781............................  Cockpit control knob shape  23.1500..............  Flightcrew interface.

[[Page 13509]]

 
23.783............................  Doors.....................
(a), (b), (c), (d)................  ..........................  23.750...............  Means of egress and
                                                                                        emergency exits.
(e), (f), (g).....................  ..........................  Means of Compliance..
23.785............................  Seats, berths, litters,     23.515 and 23.600....  Special factors of
                                     safety belts, and                                  safety, Emergency
                                     shoulder harnesses.                                landing conditions.
23.787............................  Baggage and cargo           23.600(e)............  Emergency landing
                                     compartments.                                      conditions.
23.791............................  Passenger information       23.755...............  Occupant physical
                                     signs.                                             environment.
23.803............................  Emergency evacuation......
(a)...............................  ..........................  23.750...............  Means of egress and
                                                                                        emergency exits.
(b)...............................  ..........................  Means of Compliance..
23.805............................  Flightcrew emergency exits  23.750...............  Means of egress and
                                                                                        emergency exits.
23.807............................  Emergency exits...........
(a)(3), (b)(1), (c), (d)(1),        ..........................  Means of Compliance..
 (d)(4).
Balance of 23.807.................  ..........................  23.750...............  Means of egress and
                                                                                        emergency exits.
23.811............................  Emergency exit marking....  23.750...............  Means of egress and
                                                                                        emergency exits.
23.812............................  Emergency lighting........  23.750...............  Means of egress and
                                                                                        emergency exits.
23.813............................  Emergency exit access.....
(a)...............................  ..........................  23.750...............  Means of egress and
                                                                                        emergency exits.
(b)...............................  ..........................  Means of Compliance..
CS-VLA 853........................  ..........................  23.750...............  Means of egress and
                                                                                        emergency exits.
23.815............................  Width of aisle............  23.750...............  Means of egress and
                                                                                        emergency exits.
23.831............................  Ventilation...............  23.755...............  Occupant physical
                                                                                        environment.
23.841(a), (b)(6), (c) ,(d).......  Pressurized cabins........  23.755...............  Occupant physical
                                                                                        environment.
(b)(1) through (5) and (7)........  ..........................  Means of Compliance..
23.843............................  Pressurization tests......  23.755...............  Occupant physical
                                                                                        environment.
23.851............................  Fire extinguishers........
(a) and (b).......................  ..........................  23.800...............  Fire protection outside
                                                                                        designated fire zones.
(c)...............................  ..........................  Means of Compliance..
23.853............................  Passenger and crew
                                     compartment interiors.
(a)...............................  ..........................  23.800...............  Fire protection outside
                                                                                        designated fire zones.
(b)(c) and (d)(1)(2)..............  ..........................  Means of Compliance..
(d)(3)(i), (d)(3)(iii), (d)(3)(iv)  ..........................  23.800...............  Fire protection outside
                                                                                        designated fire zones.
(e)...............................  ..........................  23.800...............  Fire protection outside
                                                                                        designated fire zones.
(f)...............................  ..........................  23.800...............  Fire protection outside
                                                                                        designated fire zones.
23.855............................  Cargo and baggage           23.800...............  Fire protection outside
                                     compartment fire                                   designated fire zones.
                                     protection.
23.856............................  Thermal/acoustic            23.800...............  Fire protection outside
                                     insulation materials.                              designated fire zones.
23.859............................  Combustion heater fire
                                     protection.
(a)...............................  ..........................  23.800...............  Fire protection outside
                                                                                        designated fire zones.
(b) thru (i)......................  ..........................  Means of Compliance..
23.863............................  Flammable fluid fire
                                     protection.
(a) and (d).......................  ..........................  23.800...............  Fire protection outside
                                                                                        designated fire zones.
(b) and (c).......................  ..........................  Means of Compliance..  Fire protection outside
                                                                                        designated fire zones.
23.865............................  Fire protection of flight   23.805...............  Fire protection in
                                     controls, engine mounts,                           designated fire zones.
                                     and other flight
                                     structure.
23.867............................  Electrical bonding and
                                     protection against
                                     lightning and static
                                     electricity.
(a) and (c).......................  ..........................  23.810...............  Lightning protection of
                                                                                        structure.
(b)...............................  ..........................  23.1320..............  Electrical and electronic
                                                                                        system lightning
                                                                                        protection.
23.871............................  Leveling means............  Means of Compliance..
----------------------------------------------------------------------------------------------------------------
                                              Subpart E--Powerplant
----------------------------------------------------------------------------------------------------------------
23.901............................  Installation..............  23.900(c)............  Powerplant Installation.
(a), (b), (f).....................  ..........................  23.900(b)............
(c)...............................  ..........................  23.900(b)............
(d) and (e).......................  ..........................  23.900(b)............  Note: In addition to
                                                                                        900(b) these rules are
                                                                                        covered under Part
                                                                                        33.63, 76, 77 and 78.
23.903............................  Engines...................

[[Page 13510]]

 
(a)...............................  ..........................  23.900(c)............
(a)(2)............................  ..........................  23.940(b)............  Powerplant ice
                                                                                        protection.
(b)(c)............................  ..........................  23.910 and 23.920....  Powerplant installation
                                                                                        hazard assessment;
                                                                                        Reversing systems.
(b)(1)............................  ..........................  23.405(d)............  Structural durability.
(d) thru (g)......................  ..........................  23.925...............  Powerplant operational
                                                                                        characteristics.
23.904............................  Automatic power reserve     23.915...............  Automatic power control
                                     system.                                            systems.
23.905............................  Propellers................
(a)...............................  ..........................  23.910(a)............  Powerplant installation
                                                                                        hazard assessment.
(b), (d), (g).....................  ..........................  .....................  Note: Intent covered
                                                                                        under part 35.
(c)...............................  ..........................  23.905...............  Propeller installation.
(e)...............................  ..........................  23.940...............  Powerplant ice
                                                                                        protection.
(f)...............................  ..........................  23.905...............  Propeller installation.
(h)...............................  ..........................  23.910...............  Powerplant installation
                                                                                        hazard assessment.
23.907............................  Propeller vibration and     .....................  Note: Intent covered
                                     fatigue.                                           under part 35.
23.909............................  Turbocharger systems......
(a) and (c).......................  ..........................  23.900...............  Powerplant installation.
(b), (d), (e).....................  ..........................  23.910...............  Powerplant installation
                                                                                        hazard assessment.
23.925............................  Propeller clearance.......  23.905(c)............  Installation.
23.929............................  Engine installation ice     23.940...............  Powerplant ice
                                     protection.                                        protection.
23.933............................  Reversing systems.........  23.920...............
(a)...............................  ..........................  23.920...............  Reversing systems.
(b)...............................  ..........................  23.920...............  Reversing systems.
23.934............................  Turbojet and turbofan       23.920...............  Note: In addition to Sec.
                                     engine thrust reverser                               23.920, this rule is
                                     systems tests.                                     covered under Sec.
                                                                                        33.97.
23.937............................  Turbopropeller-drag         23.920...............
                                     limiting systems.
(a)...............................  ..........................  23.920...............  Reversing systems.
(b)...............................  ..........................  23.920...............  Reversing systems.
23.939............................  Powerplant operating        23.925...............  In addition to 925 this
                                     characteristics.                                   rule is covered under
                                                                                        Part 33, subpart D and
                                                                                        F--Block Tests.
23.943............................  Negative acceleration.....  23.925...............  Operational
                                                                                        characteristics.
23.951............................  Fuel System--General......  23.930(a)(3).........
(a) and (b).......................  ..........................  23.930(a)(3).........  Fuel systems.
(c)...............................  ..........................  23.930(a)(3).........
(d)...............................  ..........................  23.930(a)(3).........  Intent covered under Part
                                                                                        34.
23.953............................  Fuel system independence..  23.930...............  Fuel systems.
23.954............................  Fuel system lightning       23.930...............  Fuel systems.
                                     protection.
23.955............................  Fuel flow.................  23.930...............  Fuel systems.
23.957............................  Flow between                23.930(a)(7).........  Fuel systems.
                                     interconnected tanks.
(a)...............................  ..........................  23.930(a)(7).........
(b)...............................  ..........................  23.930(a)(7).........
23.959............................  Unusable fuel supply......  23.930(c)............  Hazard assessment.
23.961............................  Fuel system hot weather     23.930(a)(3).........  Fuel systems.
                                     operation.
23.963............................  Fuel tank: general........
(a), (d), (e).....................  ..........................  23.930(b)(4).........  Fuel systems.
(b) and (c).......................  ..........................  23.930(b)(6).........
23.965............................  Fuel tank tests...........  23.930(b)(1).........
23.967............................  Fuel tank installation....  23.930(b)(6).........
23.969............................  Fuel tank expansion space.  23.930(b)(6).........
23.971............................  Fuel tank sump............  23.930(b)(6).........
23.973............................  Fuel tank filler            23.930(b)(6).........
                                     connection.
23.975............................  Fuel tank vents and         23.930(b)(6).........
                                     carburetor vapor vents.
(a)(1)............................  ..........................  23.940...............  Powerplant ice
                                                                                        protection.
23.977............................  Fuel tank outlet..........  23.930(b)(6).........  Fuel systems.
23.979............................  Pressure fueling systems..  23.930(d)............
(a) and (b).......................  ..........................  23.930(d)............  Fuel systems.
(c) and (d).......................  ..........................  23.930(d)............  Hazard assessment.
23.991............................  Fuel pumps................  23.930(a)(8).........
(a), (b), (c).....................  ..........................  23.930(a)(8).........  Fuel systems.
(d)...............................  ..........................  23.910...............  Powerplant installation
                                                                                        hazard assessment.
23.993............................  Fuel system lines and       23.930...............
                                     fittings.
23.994............................  Fuel system components....  23.930(a)(7).........  Hazard assessment.
23.995............................  Fuel valves and controls..  23.930(d)............
(a)...............................  ..........................  23.930(d)............  Powerplant installation.
(b) thru (g)......................  ..........................  23.930(d)............
23.997............................  Fuel strainer or filter...  23.930(a)............
(a) thru (d)......................  ..........................  23.930(a)(6).........  Fuel systems.
(e)...............................  ..........................  23.950...............  Powerplant ice
                                                                                        protection.
23.999............................  Fuel system drains........  23.930(a)(4).........  Fuel systems.
23.1001...........................  Fuel jettisoning system...  23.930(b)(5).........
(a)...............................  ..........................  23.930(b)(5).........  Fuel systems.
(b) thru (g)......................  ..........................  23.930(b)(5).........
(h)...............................  ..........................  23.910...............  Powerplant installation
                                                                                        hazard assessment.
23.1011...........................  General...................  23.935...............  Intent covered under Part
                                                                                        33.

[[Page 13511]]

 
23.1013...........................  Oil tanks.................  23.935(b)(1).........  Intent covered under Part
                                                                                        33.
23.1015...........................  Oil tank tests............  23.935(b)(1).........  Intent covered under Part
                                                                                        33.
23.1017...........................  Oil lines and fittings....  23.935(b)(1).........  Intent covered under Part
                                                                                        33.
23.1019...........................  Oil strainer or filter....  23.935(b)(2).........  Intent covered under Part
                                                                                        33.
23.1021...........................  Oil system drains.........  23.935(b)(2).........  Intent covered under Part
                                                                                        33.
23.1023...........................  Oil radiators.............  23.935(b)(1).........  Intent covered under Part
                                                                                        33.
23.1027...........................  Propeller feathering        23.935(b)(2).........  Hazard assessment.
                                     system.
23.1041...........................  Cooling--General..........  23.940(a)............  Intent covered under Part
                                                                                        33.
23.1043...........................  Cooling tests.............  23.940(a)............  Intent covered under Part
                                                                                        33.
23.1045...........................  Cooling test procedures     23.940(a)............  Intent covered under Part
                                     for turbine engine                                 33.
                                     powered airplanes.
23.1047...........................  Cooling test procedures     23.940(a)............  Intent covered under Part
                                     for reciprocating engine                           33.
                                     powered airplanes.
23.1061...........................  Installation..............  23.940(b)............  Intent covered under Part
                                                                                        33.
23.1063...........................  Coolant tank tests........  23.940(b)............  Intent covered under Part
                                                                                        33.
23.1091...........................  Air induction system......  23.945(a)............  Intent covered under Part
                                                                                        33.
23.1093...........................  Induction system icing      23.940...............  Powerplant ice
                                     protection.                                        protection.
23.1095...........................  Carburetor deicing fluid    23.940...............  Powerplant ice
                                     flow rate.                                         protection.
23.1097...........................  Carburetor deicing fluid    23.940...............  Powerplant ice
                                     system capacity.                                   protection.
23.1099...........................  Carburetor deicing fluid    23.940...............  Powerplant ice
                                     system detail design.                              protection.
23.1101...........................  Induction air preheater     23.935...............
                                     design.
(a)...............................  ..........................  23.935...............  Powerplant induction and
                                                                                        exhaust systems.
(b) and (c).......................  ..........................  23.935...............
23.1103...........................  Induction system ducts....  23.935...............  Powerplant induction and
                                                                                        exhaust systems.
23.1105...........................  Induction system screens..  23.935...............
23.1107...........................  Induction system filters..  23.935...............  Powerplant induction and
                                                                                        exhaust systems.
23.1109...........................  Turbocharger bleed air      23.910...............
                                     system.
23.1111...........................  Turbine engine bleed air    23.910...............
                                     system.
(a) and (c).......................  ..........................  23.910...............  Hazard assessment.
(b)...............................  ..........................  23.910...............
23.1121...........................  Exhaust System--General...  23.935...............
(a) thru (g)......................  ..........................  23.935...............  Powerplant induction and
                                                                                        exhaust systems.
(h)...............................  ..........................  23.910...............  Hazard assessment.
23.1123...........................  Exhaust system............  23.910...............  Hazard assessment.
23.1125...........................  Exhaust heat exchangers...  23.910...............
(a)...............................  ..........................  23.910...............  Hazard assessment.
(b)...............................  ..........................  23.910...............
23.1141...........................  Powerplant controls:        23.1505(b)...........
                                     general (a)(c)(g).
                                    (b)(d)(e) and (f).........  23.910...............  Powerplant installation
                                                                                        hazard assessment.
23.1142...........................  Auxiliary power unit        23.1500(b)...........
                                     controls.
23.1143...........................  Engine controls...........  23.1500(b)...........
23.1145...........................  Ignition switches.........  23.1500(b)...........
23.1147...........................  Mixture controls..........  23.1500(b)...........
23.1149...........................  Propeller speed and pitch   23.1500(b)...........
                                     controls.
23.1153...........................  Propeller feathering        23.1500(b)...........
                                     controls.
23.1155...........................  Turbine engine reverse      23.910 and 23.1500(b)  Hazard assessment.
                                     thrust and propeller
                                     pitch settings below the
                                     flight regime.
23.1157...........................  Carburetor air temperature  23.1500(b)...........
                                     controls.
23.1163...........................  Powerplant accessories....  23.910(a)............  Powerplant installation
                                                                                        hazard assessment.
(a), (c), (e).....................  ..........................  23.910(a)............
(b) and (d).......................  ..........................  23.910(a)............
23.1165...........................  Engine ignition systems...  Means of Compliance..
23.1181...........................  Designated fire zones:      23.1000(a)...........  Powerplant fire
                                     regions included.                                  protection.
23.1182...........................  Nacelle areas behind        23.1000(b)...........
                                     firewalls.
23.1183...........................  Lines, fittings, and        23.1000(b)...........
                                     components.
23.1189...........................  Shutoff means.............  23.1000(c)...........
23.1191...........................  Firewalls.................  23.1000(d)...........
(a) thru (e), (g), (h)............  ..........................  23.1000(d)...........
(f)...............................  ..........................  23.910...............  Powerplant installation
                                                                                        hazard assessment.
23.1192...........................  Engine accessory            23.1000(d)...........
                                     compartment diaphragm.
23.1193...........................  Cowling and nacelle.......  23.1000(d)...........
(a) thru (e)......................  ..........................  23.1000(d)...........
(f) and (g).......................  ..........................  23.1000(d)...........  Hazard assessment.
23.1195...........................  Fire extinguishing systems  23.1000(e)...........
23.1197...........................  Fire extinguishing agents.  23.1000(e)...........
23.1199...........................  Extinguishing agent         23.1000(e)...........
                                     containers.
23.1201...........................  Fire extinguishing system   23.1000(e)...........
                                     materials.
(a)...............................  ..........................  23.1000(e)...........  Hazard assessment.
(b)...............................  ..........................  23.1000(e)...........
23.1203...........................  Fire detector system......  23.1000(f)...........
(a), (d), (e).....................  ..........................  23.1000(f)...........
(b) and (c).......................  ..........................  23.1000(f)...........  Hazard assessment.
----------------------------------------------------------------------------------------------------------------

[[Page 13512]]

 
                                              Subpart F--Equipment
----------------------------------------------------------------------------------------------------------------
23.1301...........................  Function and installation.
(a)...............................  ..........................  23.1300(a) and         Airplane level systems
                                                                 23.1305(a).            requirements; Function
                                                                                        and installation.
(b)...............................  ..........................  23.1305(a)(3)........  Function and
                                                                                        installation.
(c)...............................  ..........................  23.1305(a)(2)........  Function and
                                                                                        installation.
23.1303...........................  Flight and navigation       23.1300, 23.1310,      Airplane level systems
                                     instruments.                23.1305(b) and (c),    requirements; Flight,
                                                                 and 23.1330(c).        navigation, and
                                                                                        powerplant instruments;
                                                                                        Function and
                                                                                        installation; System
                                                                                        power generation,
                                                                                        storage, and
                                                                                        distribution.
23.1305...........................  Powerplant instruments....  23.1300, 23.1310 and   Airplane level systems
                                                                 23.1305(c).            requirements; Flight,
                                                                                        navigation, and
                                                                                        powerplant instruments;
                                                                                        Function and
                                                                                        installation.
23.1306...........................  Electrical and electronic   23.1320..............  Electrical and electronic
                                     system lightning                                   system lightning
                                     protection.                                        protection.
23.1307...........................  Miscellaneous equipment...  23.1300 and 23.1310..  Airplane level systems
                                                                                        requirements; Flight,
                                                                                        navigation, and
                                                                                        powerplant instruments.
23.1308...........................  High-Intensity Radiated     23.1325..............  High-intensity Radiated
                                     Fields (HIRF) protection.                          Fields (HIRF)
                                                                                        protection.
23.1309...........................  Equipment, systems, and     23.1315..............  Equipment, systems, and
                                     installations.                                     installations.
(a)(1)............................  ..........................  23.1300(a)...........  Airplane level systems
                                                                                        requirements.
(a)(2)............................  ..........................  23.1300(b)...........  Airplane level systems
                                                                                        requirements.
(b)...............................  ..........................  .....................  --Deleted--.
(c)...............................  ..........................  23.1315(b)...........  Equipment, systems, and
                                                                                        installations.
(b)...............................  ..........................  23.1305(c)...........  Function and
                                                                                        installation.
23.1310...........................  Power source capacity and   23.1330..............  System power generation,
                                     distribution.                                      storage, and
                                                                                        distribution.
23.1311...........................  Electronic display          23.1300 and 23.1310..  Airplane level systems
                                     instrument systems.                                requirements; Flight,
                                                                                        navigation, and
                                                                                        powerplant instruments.
23.1321...........................  Arrangement and visibility  23.1300 and 23.1310..  Airplane level systems
                                                                                        requirements; Flight,
                                                                                        navigation, and
                                                                                        powerplant instruments.
23.1322...........................  Warning, caution, and       23.1305(b) and (c)...  Flight, navigation, and
                                     advisory lights.                                   powerplant instruments.
23.1323...........................  Airspeed indicating system  23.1300, 23.1305,      Airplane level systems
                                                                 23.1310, and 1315.     requirements; Function
                                                                                        and installation;
                                                                                        Flight, navigation, and
                                                                                        powerplant instruments;
                                                                                        and Equipment, systems,
                                                                                        and installations.
(d)...............................  ..........................  23.1405..............  Flight in icing
                                                                                        conditions.
23.1325...........................  Static pressure system....  23.1300, 23.1310, and  Airplane level systems
                                                                 23.1315.               requirements; Flight,
                                                                                        navigation, and
                                                                                        powerplant instruments;
                                                                                        and Equipment, systems,
                                                                                        and installations.
(b)(3) and (g)....................  ..........................  1405.................  Flight in icing
                                                                                        conditions.
23.1326...........................  Pitot heat indication       23.1305..............  Function and
                                     systems.                                           installation.
23.1327...........................  Magnetic direction          23.1300, 23.1305 and   Airplane level systems
                                     indicator.                  23.1310.               requirements; Function
                                                                                        and installation;
                                                                                        Flight, navigation, and
                                                                                        powerplant instruments.
23.1329...........................  Automatic pilot system....  23.1300, 23.1305 and   Airplane level systems
                                                                 23.1315.               requirements; Function
                                                                                        and installation;
                                                                                        Equipment, systems, and
                                                                                        installations.
(a)...............................  ..........................  23.1300 and 23.1315..  Airplane level systems
                                                                                        requirements; Equipment,
                                                                                        systems, and
                                                                                        installations.
(b)...............................  ..........................  23.700 and 23.1500...  Flight control systems;
                                                                                        Flightcrew interface.
(c)...............................  ..........................  23.1305..............  Function and
                                                                                        installation.
(d)...............................  ..........................  23.700 and 23.1500...  Flight control systems;
                                                                                        Flightcrew interface.
(e), (f), (g).....................  ..........................  23.1300 and 23.1315..  Airplane level systems
                                                                                        requirements; Equipment,
                                                                                        systems, and
                                                                                        installations.
(h)...............................  ..........................  23.1305..............  Function and
                                                                                        installation.
23.1331...........................  Instruments using a power
                                     source.
(a)...............................  ..........................  23.1305(c)...........  Function and
                                                                                        installation.
(b)...............................  ..........................  23.1315(b) and         Equipment, systems, and
                                                                 23.1330(b).            installations; System
                                                                                        power generation,
                                                                                        storage, and
                                                                                        distribution.
(c)...............................  ..........................  23.1310(b)...........  Flight, navigation, and
                                                                                        powerplant instruments.
23.1335...........................  Flight director systems...  23.1300, 23.1305,      Airplane level systems;
                                                                 23.1315, and 23.1500.  Function and
                                                                                        installation; Equipment
                                                                                        systems and
                                                                                        installations; and
                                                                                        Flightcrew interface.
23.1337...........................  Powerplant instruments
                                     installation.
(a)...............................  ..........................  23.800(g)............  Fire protection outside
                                                                                        designated fire zones.
                                                                23.930...............  Fuel systems.
(b)...............................  ..........................  23.1305(c) and (d)...  Function and
                                                                                        installation.

[[Page 13513]]

 
                                                                23.1310(a)...........  Flight, navigation, and
                                                                                        powerplant instruments.
                                                                23.1315(b)...........  Equipment, systems, and
                                                                                        installations.
(c)...............................  ..........................  23.1315(b)...........  Equipment, systems, and
                                                                                        installations.
(d)...............................  ..........................  23.1305(c)...........  Function and
                                                                                        installation.
                                                                23.1310(a)...........  Flight, navigation, and
                                                                                        powerplant instruments.
23.1351...........................  Electrical Systems--        23.1300..............  Airplane level systems
                                     General.                                           requirements.
                                                                23.1305..............  Function and
                                                                                        installation.
                                                                23.1315..............  Equipment, systems, and
                                                                                        installations.
                                                                23.1330..............  System power generation,
                                                                                        storage, and
                                                                                        distribution.
23.1353...........................  Storage battery design and  23.1300..............  Airplane level systems
                                     installation.                                      requirements.
                                                                23.1305..............  Function and
                                                                                        installation.
                                                                23.1315..............  Equipment, systems, and
                                                                                        installations.
                                                                23.1330..............  System power generation,
                                                                                        storage, and
                                                                                        distribution.
23.1357...........................  Circuit protective devices  23.1300..............  Airplane level systems
                                                                                        requirements.
                                                                23.1305..............  Function and
                                                                                        installation.
                                                                23.1315..............  Equipment, systems, and
                                                                                        installations.
                                                                23.1330..............  System power generation,
                                                                                        storage, and
                                                                                        distribution.
23.1359...........................  Electrical system fire
                                     protection.
(a)...............................  ..........................  Means of Compliance..
(b)...............................  ..........................  805..................  Flammability in
                                                                                        designated fire zones.
(c)...............................  ..........................  800..................  Fire protection outside
                                                                                        designated fire zones.
23.1361...........................  Master switch arrangement.  23.1300 and 23.1305..  Airplane level systems
                                                                                        requirements; Function
                                                                                        and installation.
23.1365...........................  Electrical cables and       23.1305..............  Function and
                                     equipment.                                         installation.
(b)...............................  ..........................  23.805...............  Flammability in
                                                                                        designated fire zones.
(a), (c) thru (f).................  ..........................  Means of Compliance..
23.1367...........................  Switches..................
(a) and (b).......................  ..........................  23.1305..............  Function and
                                                                                        installation.
(c) and (d).......................  ..........................  23.1500..............  Flightcrew interface.
23.1381...........................  Instrument lights.........
(a) and (b).......................  ..........................  23.1500..............  Flightcrew interface.
(c)...............................  ..........................  23.1335..............  External and cockpit
                                                                                        lighting.
23.1383(a), (b), (c)..............  Taxi and landing lights...  23.1335..............  External and cockpit
                                                                                        lighting.
(d)...............................  Taxi and landing lights...  23.800...............  Fire protection outside
                                                                                        designated fire zones.
23.1385(a), (b), (c)..............  Position light system       23.1335..............  External and cockpit
                                     installation.                                      lighting.
(d)...............................  Position light system       23.800...............  Fire protection outside
                                     installation.                                      designated fire zones.
23.1387...........................  Position light system       23.1335..............  External and cockpit
                                     dihedral angles.                                   lighting.
23.1389...........................  Position light              23.1335..............  External and cockpit
                                     distribution and                                   lighting.
                                     intensities.
23.1391...........................  Minimum intensities in the  23.1335..............  External and cockpit
                                     horizontal plane of                                lighting.
                                     position lights.
23.1393...........................  Minimum intensities in any  23.1335..............  External and cockpit
                                     vertical plane of                                  lighting.
                                     position lights.
23.1395...........................  Maximum intensities in      23.1335..............  External and cockpit
                                     overlapping beams of                               lighting.
                                     position lights.
23.1397...........................  Color specifications......  23.1335..............  External and cockpit
                                                                                        lighting.
23.1399...........................  Riding light..............  23.1335..............  External and cockpit
                                                                                        lighting.
23.1401...........................  Anticollision light system
(a), (a)(1).......................  ..........................  23.1335..............  External and cockpit
                                                                                        lighting.
(a)(2)............................  ..........................  Means of Compliance..
(b) thru (f)......................  ..........................  23.1335..............  External and cockpit
                                                                                        lighting.
23.1411...........................  Safety Equipment-General..
(a), (b)(1).......................  ..........................  23.1400..............  Safety equipment.
(b)(2)............................  ..........................  23.600...............  Emergency conditions.
23.1415...........................  Ditching equipment........  23.1400..............  Safety equipment.
(a), (c), (d).....................  ..........................  23.1400..............  Safety equipment.
(b)...............................  ..........................  Means of Compliance..
23.1416...........................  Pneumatic de-icer boot      23.1300..............  Airplane level systems
                                     system.                                            requirements.
                                    ..........................  23.1305..............  Function and
                                                                                        installation.
23.1419...........................  Ice protection............  23.230...............  Flight in icing
                                                                                        conditions.
                                                                23.1405..............  Performance and flight
                                                                                        characteristics
                                                                                        requirements for flight
                                                                                        in icing conditions.
23.1431...........................  Electronic equipment......  23.1315..............  Equipment, systems and
                                                                                        installations.
23.1435...........................  Hydraulic systems.........
(a)(4) and (b)....................  ..........................  23.1410..............  Pressurized system
                                                                                        elements.

[[Page 13514]]

 
(a), (a)(1) through (3), (c)......  ..........................  Means of Compliance..
23.1437...........................  Accessories for             23.1410..............  Pressurized system
                                     multiengine airplanes.                             elements.
23.1438...........................  Pressurization and
                                     pneumatic systems.
(a), (b)..........................  ..........................  23.1410..............  Pressurized system
                                                                                        elements.
(c)...............................  ..........................  Means of Compliance..
                                                                23.1410(e)...........  Pressurized system
                                                                                        elements.
23.1441...........................  Oxygen equipment and
                                     supply.
(a)...............................  ..........................  Means of Compliance..
(b)...............................  ..........................  23.1315..............  Equipment, systems and
                                                                                        installation.
(c), (d), (e).....................  ..........................  23.755...............  Occupant physical
                                                                                        environment.
23.1443(a), (b), (c)..............  Minimum mass flow of        23.755...............  Occupant physical
                                     supplemental oxygen.                               environment.
(d)...............................  ..........................  Definition...........
23.1445...........................  Oxygen distribution system  23.755...............  Occupant physical
                                                                                        environment.
23.1447...........................  Equipment standards for
                                     oxygen dispensing units.
(a), (b), (c), (d), (f)...........  ..........................  23.755...............  Occupant physical
                                                                                        environment.
(e)...............................  ..........................  Means of Compliance..
23.1449...........................  Means for determining use   23.755...............  Occupant physical
                                     of oxygen.                                         environment.
23.1450...........................  Chemical oxygen generators
(a)...............................  ..........................  Means of Compliance..
(b)...............................  ..........................  23.1315..............  Equipment, systems and
                                                                                        installation.
(c)...............................  ..........................  23.1505..............  Instrument markings,
                                                                                        control markings, and
                                                                                        placards.
23.1451...........................  Fire protection for oxygen  23.1315..............  Equipment, systems and
                                     equipment.                                         installation.
23.1453...........................  Protection of oxygen        23.1315..............  Equipment, systems and
                                     equipment from rupture.                            installation.
23.1457...........................  Cockpit voice recorders...  23.1457..............  No Change.
23.1459...........................  Flight recorders..........
(a)(1)............................  ..........................  23.1459..............  Flight data recorders.
(a)(2) thru (d)...................  ..........................  23.1459..............  No Change.
23.1461...........................  Equipment containing high   23.755...............  Occupant physical
                                     energy rotors.                                     environment.
----------------------------------------------------------------------------------------------------------------
                                Subpart G--Operating Limitations and Information
----------------------------------------------------------------------------------------------------------------
23.1501...........................  General...................  23.1505..............  Instrument markings,
                                                                                        control markings, and
                                                                                        placards.
23.1505...........................  Airspeed limitations......  23.1505..............  Instrument markings,
                                                                                        control markings, and
                                                                                        placards.
23.1507...........................  Operating maneuvering       23.1505..............  Instrument markings,
                                     speed.                                             control markings, and
                                                                                        placards.
23.1511...........................  Flap extended speed.......  23.1505..............  Instrument markings,
                                                                                        control markings, and
                                                                                        placards.
23.1513...........................  Minimum control speed.....  23.1505..............  Instrument markings,
                                                                                        control markings, and
                                                                                        placards.
23.1519...........................  Weight and center of        23.1505..............  Instrument markings,
                                     gravity.                                           control markings, and
                                                                                        placards.
23.1521...........................  Powerplant limitations....  23.1505..............  Instrument markings,
                                                                                        control markings, and
                                                                                        placards.
23.1522...........................  Auxiliary power unit        23.1505..............  Instrument markings,
                                     limitations.                                       control markings, and
                                                                                        placards.
23.1523...........................  Minimum flight crew.......  23.1505..............  Instrument markings,
                                                                                        control markings, and
                                                                                        placards.
23.1524...........................  Maximum passenger seating   23.1505..............  Instrument markings,
                                     configuration.                                     control markings, and
                                                                                        placards.
23.1525...........................  Kinds of operation........  23.1300..............  Airplane level system
                                                                                        requirements.
                                                                23.1505..............  Instrument markings,
                                                                                        control markings, and
                                                                                        placards.
23.1527...........................  Maximum operating altitude  23.1505..............  Instrument markings,
                                                                                        control markings, and
                                                                                        placards.
23.1529...........................  Instructions for continued  23.1515..............  Instructions for
                                     airworthiness.                                     continued airworthiness.
23.1541...........................  Marking and Placards--      23.1505..............  Instrument markings,
                                     General.                                           control markings, and
                                                                                        placards.
23.1543...........................  Instrument marking:         23.1505..............  Instrument markings,
                                     general.                                           control markings, and
                                                                                        placards.
23.1545...........................  Airspeed indicator........  23.1505..............  Instrument markings,
                                                                                        control markings, and
                                                                                        placards.
23.1547...........................  Magnetic direction          23.1505..............  Instrument markings,
                                     indicator.                                         control markings, and
                                                                                        placards.
23.1549...........................  Powerplant and auxiliary    23.1505..............  Instrument markings,
                                     power unit instruments.                            control markings, and
                                                                                        placards.
23.1551...........................  Oil quantity indicator....  23.1505..............  Instrument markings,
                                                                                        control markings, and
                                                                                        placards.

[[Page 13515]]

 
23.1553...........................  Fuel quantity indicator...  23.1505..............  Instrument markings,
                                                                                        control markings, and
                                                                                        placards.
23.1555...........................  Control markings..........  23.1505..............  Instrument markings,
                                                                                        control markings, and
                                                                                        placards.
23.1557...........................  Miscellaneous marking and   23.1505..............  Instrument markings,
                                     placards.                                          control markings, and
                                                                                        placards.
23.1559...........................  Operating limitations       23.1505..............  Instrument markings,
                                     placard.                                           control markings, and
                                                                                        placards.
23.1561...........................  Safety equipment..........  23.1505..............  Instrument markings,
                                                                                        control markings, and
                                                                                        placards.
23.1563...........................  Airspeed placards.........  23.1505..............  Instrument markings,
                                                                                        control markings, and
                                                                                        placards.
23.1567...........................  Flight maneuver placard...  23.1505..............  Instrument markings,
                                                                                        control markings, and
                                                                                        placards.
23.1581...........................  Airplane Flight Manual and  23.1510..............  Airplane flight manual.
                                     Approved Manual Material--
                                     General.
23.1583...........................  Operating limitations.....  23.1510..............  Airplane flight manual.
23.1585...........................  Operating procedures......  23.1510..............  Airplane flight manual.
23.1587...........................  Performance information...  23.1510..............  Airplane flight manual.
23.1589...........................  Loading information.......  23.1510..............  Airplane flight manual.
Appendix A........................  Simplified Design Load      Means of Compliance..
                                     Criteria.
Appendix B........................  [Reserved]................  .....................  --Deleted--
Appendix C........................  Basic Landing Conditions..  Means of Compliance..
Appendix D........................  Wheel Spin-Up and Spring-   Means of Compliance..
                                     Back Loads.
Appendix E........................  [Reserved]................  .....................  --Deleted--
Appendix F........................  Test Procedure............  Means of Compliance..
Appendix G........................  Instructions for Continued  Appendix A...........  Instructions for
                                     Airworthiness.                                     Continued Airworthiness.
Appendix H........................  Installation of An          Means of Compliance..
                                     Automatic Power Reserve
                                     (APR) System.
Appendix I........................  Seaplane Loads............  Means of Compliance..
Appendix J........................  HIRF Environments and       Means of Compliance..
                                     Equipment HIRF Test
                                     Levels.
----------------------------------------------------------------------------------------------------------------

Appendix 2 to the Preamble--Abbreviations and Acronyms Frequently Used 
in This Document

AD Airworthiness Directive
AFM Airplane Flight Manual
ARC Aviation Rulemaking Committee
ASTM ASTM International
CAA Civil Aviation Authority
CAR Civil Aviation Regulations
Cf Confer (to identify a source or a usage citation for a word or 
phrase)
CPS Certification Process Study
CS Certification Specification
CS-VLA Certification Specification--Very Light Aeroplanes
EASA European Aviation Safety Agency
ELOS Equivalent Level of Safety
FR Federal Register
GA General Aviation
HIRF High-Intensity Radiated Field
IFR Instrument Flight Rules
KCAS Knots Calibrated Airspeeds
LOC Loss of Control
NPRM Notice of Proposed Rulemaking
NTSB National Transportation Safety Board
OMB Office of Management and Budget
SAE SAE International
SLD Supercooled Large Droplet
TCDS Type Certificate Data Sheet
VA Design Maneuvering Speed
VC Design Cruising Speed
VD Design Dive Speed
VMC Minimum Control Speed
VMO/MMO Maximum Operating Limit Speed
VFR Visual Flight Rules
VSO Stalling speed or the minimum steady flight speed in the 
landing configuration

List of Subjects

14 CFR Part 21

    Aircraft, Aviation safety, Recording and recordkeeping 
requirements.

14 CFR Part 23

    Aircraft, Aviation Safety, Signs and symbols.

14 CFR Part 35

    Aircraft, Aviation safety.

14 CFR Part 43

    Aircraft, Aviation safety, Reporting and recordkeeping 
requirements.

14 CFR Part 91

    Air traffic control, Aircraft, Airmen, Airports, Aviation safety, 
Reporting and recordkeeping requirements.

14 CFR Part 121

    Aircraft, Airmen, Aviation safety, Reporting and recordkeeping 
requirements.

14 CFR Part 135

    Aircraft, Airmen, Aviation safety, Reporting and recordkeeping 
requirements.

The Proposed Amendment

    In consideration of the foregoing, the Federal Aviation 
Administration proposes to amend chapter I of title 14, Code of Federal 
Regulations as follows:

PART 21--CERTIFICATION PROCEDURES FOR PRODUCTS AND ARTICLES

0
1. The authority citation for part 21 is revised to read as follows:

    Authority: 42 U.S.C. 7572; 49 U.S.C. 106(f), 106(g), 40105, 
40113, 44701-44702, 44704, 44707, 44709, 44711, 44713, 44715, 45303.

0
2. In Sec.  21.9, revise paragraphs (a)(5), (a)(6), (b), and (c) 
introductory text, and add paragraph (a)(7) to read as follows:


Sec.  21.9  Replacement and modification articles.

    (a) * * *
    (5) Produced by an owner or operator for maintaining or altering 
that owner or operator's product;
    (6) Fabricated by an appropriately rated certificate holder with a 
quality system, and consumed in the repair or alteration of a product 
or article in

[[Page 13516]]

accordance with part 43 of this chapter; or
    (7) Produced in any other manner approved by the FAA.
    (b) Except as provided in paragraphs (a)(1), (a)(2) and (a)(7) of 
this section, a person who produces a replacement or modification 
article for sale may not represent that part as suitable for 
installation on a type-certificated product.
    (c) Except as provided in paragraphs (a)(1), (a)(2) and (a)(7) of 
this section, a person may not sell or represent an article as suitable 
for installation on an aircraft type-certificated under Sec.  
21.25(a)(2) or Sec.  21.27 unless that article--
* * * * *
0
3. In Sec.  21.17, revise paragraph (a) introductory text to read as 
follows:


Sec.  21.17  Designation of applicable regulations.

    (a) Except as provided in Sec. Sec.  25.2, 27.2, 29.2, and in parts 
26, 34, and 36 of this subchapter, an applicant for a type certificate 
must show that the aircraft, aircraft engine, or propeller concerned 
meets--
* * * * *
0
4. In Sec.  21.24, revise paragraph (a)(1)(i) to read as follows:


Sec.  21.24  Issuance of type certificate: primary category aircraft.

    (a) * * *
    (1) * * *
    (i) Is unpowered; is an airplane powered by a single, naturally 
aspirated engine with a 61-knot or less Vso stall speed as 
defined in Sec.  23.49 of this chapter, at amendment 23-62, effective 
on Jan 31, 2012; or is a rotorcraft with a 6-pound per square foot main 
rotor disc loading limitation, under sea level standard day conditions;
* * * * *
0
5. In Sec.  21.35, revise paragraph (b)(2) to read as follows:


Sec.  21.35  Flight tests.

* * * * *
    (b) * * *
    (2) For aircraft to be certificated under this subchapter, except 
gliders, and except for low-speed airplanes, as defined in part 23 of 
this chapter, of 6,000 pounds or less maximum weight that are to be 
certificated under part 23 of this chapter, to determine whether there 
is reasonable assurance that the aircraft, its components, and its 
equipment are reliable and function properly.
* * * * *
0
6. In Sec.  21.50, revise paragraph (b) to read as follows:


Sec.  21.50  Instructions for continued airworthiness and 
manufacturer's maintenance manuals having airworthiness limitations 
sections.

* * * * *
    (b) The holder of a design approval, including either a type 
certificate or supplemental type certificate for an aircraft, aircraft 
engine, or propeller for which application was made after January 28, 
1981, must furnish at least one set of complete Instructions for 
Continued Airworthiness to the owner of each type aircraft, aircraft 
engine, or propeller upon its delivery, or upon issuance of the first 
standard airworthiness certificate for the affected aircraft, whichever 
occurs later. The Instructions for Continued Airworthiness must be 
prepared in accordance with Sec. Sec.  23.1515, 25.1529, 25.1729, 
27.1529, 29.1529, 31.82, 33.4, 35.4, or part 26 of this subchapter, or 
as specified in the applicable airworthiness criteria for special 
classes of aircraft defined in Sec.  21.17(b), as applicable. If the 
holder of a design approval chooses to designate parts as commercial, 
it must include in the Instructions for Continued Airworthiness a list 
of commercial parts submitted in accordance with the provisions of 
paragraph (c) of this section. Thereafter, the holder of a design 
approval must make those instructions available to any other person 
required by this chapter to comply with any of the terms of those 
instructions. In addition, changes to the Instructions for Continued 
Airworthiness shall be made available to any person required by this 
chapter to comply with any of those instructions.
* * * * *
0
7. In Sec.  21.101 revise paragraphs (b) introductory text, and (c) to 
read as follows:


Sec.  21.101  Designation of applicable regulations.

* * * * *
    (b) Except as provided in paragraph (g) of this section, if 
paragraphs (b)(1), (2), or (3) of this section apply, an applicant may 
show that the change and areas affected by the change comply with an 
earlier amendment of a regulation required by paragraph (a) of this 
section, and of any other regulation the FAA finds is directly related. 
However, the earlier amended regulation may not precede either the 
corresponding regulation incorporated by reference in the type 
certificate, or any regulation in Sec. Sec.  25.2, 27.2, or Sec.  29.2 
of this chapter that is related to the change. The applicant may show 
compliance with an earlier amendment of a regulation for any of the 
following:
* * * * *
    (c) An applicant for a change to an aircraft (other than a 
rotorcraft) of 6,000 pounds or less maximum weight, to a non-turbine 
rotorcraft of 3,000 pounds or less maximum weight, to a simple, to a 
level 1 low speed, or to a level 2 low speed airplane may show that the 
change and areas affected by the change comply with the regulations 
incorporated by reference in the type certificate. However, if the FAA 
finds that the change is significant in an area, the FAA may designate 
compliance with an amendment to the regulation incorporated by 
reference in the type certificate that applies to the change and any 
regulation that the FAA finds is directly related, unless the FAA also 
finds that compliance with that amendment or regulation would not 
contribute materially to the level of safety of the product or would be 
impractical.
* * * * *
0
8. Revise part 23 to read as follows:

PART 23--AIRWORTHINESS STANDARDS: NORMAL CATEGORY AIRPLANES

Sec.
Subpart A--General
23.1 Applicability and definitions.
23.5 Certification of normal category airplanes.
23.10 Accepted means of compliance.
Subpart B--Flight

Performance

23.100 Weight and center of gravity.
23.105 Performance data.
23.110 Stall speed.
23.115 Takeoff performance.
23.120 Climb requirements.
23.125 Climb information.
23.130 Landing.

Flight Characteristics

23.200 Controllability.
23.205 Trim.
23.210 Stability.
23.215 Stall characteristics, stall warning, and spins.
23.220 Ground and water handling characteristics.
23.225 Vibration, buffeting, and high-speed characteristics.
23.230 Performance and flight characteristics requirements for 
flight in icing conditions.
Subpart C--Structures
23.300 Structural design envelope.
23.305 Interaction of systems and structures.

Structural Loads

23.310 Structural design loads.

[[Page 13517]]

23.315 Flight load conditions.
23.320 Ground and water load conditions.
23.325 Component loading conditions.
23.330 Limit and ultimate loads.

Structural Performance

23.400 Structural strength.
23.405 Structural durability.
23.410 Aeroelasticity.

Design

23.500 Structural design.
23.505 Protection of structure.
23.510 Materials and processes.
23.515 Special factors of safety.

Structural Occupant Protection

23.600 Emergency conditions.
Subpart D--Design and Construction
23.700 Flight control systems.
23.705 Landing gear systems.
23.710 Buoyancy for seaplanes and amphibians.

Occupant System Design Protection

23.750 Means of egress and emergency exits.
23.755 Occupant physical environment.

Fire and High Energy Protection

23.800 Fire protection outside designated fire zones.
23.805 Fire protection in designated fire zones.
23.810 Lightning protection of structure.
Subpart E--Powerplant
23.900 Powerplant installation.
23.905 Propeller installation.
23.910 Powerplant installation hazard assessment.
23.915 Automatic power control systems.
23.920 Reversing systems.
23.925 Powerplant operational characteristics.
23.930 Fuel system.
23.935 Powerplant induction and exhaust systems.
23.940 Powerplant ice protection.
23.1000 Powerplant fire protection.
Subpart F--Equipment
23.1300 Airplane level systems requirements.
23.1305 Function and installation.
23.1310 Flight, navigation, and powerplant instruments.
23.1315 Equipment, systems, and installations.
23.1320 Electrical and electronic system lightning protection.
23.1325 High-intensity Radiated Fields (HIRF) protection.
23.1330 System power generation, storage, and distribution.
23.1335 External and cockpit lighting.
23.1400 Safety equipment.
23.1405 Flight in icing conditions.
23.1410 Pressurized system elements.
23.1457 Cockpit voice recorders.
23.1459 Flight data recorders.
Subpart G--Flightcrew Interface and Other Information
23.1500 Flightcrew interface.
23.1505 Instrument markings, control markings and placards.
23.1510 Airplane flight manual.
23.1515 Instructions for continued airworthiness.
Appendix A to Part 23--Instructions for Continued Airworthiness

    Authority: 49 U.S.C. 106(f), 106(g), 40113, 44701-44702, 44704, 
Pub. L. 113-53, 127 Stat. 584 (49 U.S.C. 44704) note.

Subpart A--General


Sec.  23.1  Applicability and definitions.

    (a) This part prescribes airworthiness standards for the issuance 
of type certificates, and changes to those certificates, for airplanes 
in the normal category.
    (b) For the purposes of this part, the following definitions apply:
    (1) Continued safe flight and landing means an airplane is capable 
of continued controlled flight and landing, possibly using emergency 
procedures, without requiring exceptional pilot skill or strength. Upon 
landing, some airplane damage may occur as a result of a failure 
condition.
    (2) Designated fire zone means a zone where catastrophic 
consequences from fire in that zone must be mitigated by containing the 
fire in that zone.
    (3) Empty weight means the weight of the airplane with fixed 
ballast, unusable fuel, full operating fluids, and other fluids 
required for normal operation of airplane systems.


Sec.  23.5  Certification of normal category airplanes.

    (a) Certification in the normal category applies to airplanes with 
a passenger-seating configuration of 19 or less and a maximum 
certificated takeoff weight of 19,000 pounds or less.
    (b) Airplane certification levels are:
    (1) Level 1--for airplanes with a maximum seating configuration of 
0 to 1 passengers.
    (2) Level 2--for airplanes with a maximum seating configuration of 
2 to 6 passengers.
    (3) Level 3--for airplanes with a maximum seating configuration of 
7 to 9 passengers.
    (4) Level 4--for airplanes with a maximum seating configuration of 
10 to 19 passengers.
    (c) Airplane performance levels are:
    (1) Low speed--for airplanes with a VC or VMO 
<= 250 Knots Calibrated Airspeed (KCAS) (and MMO <= 0.6).
    (2) High speed--for airplanes with a VC or 
VMO > 250 KCAS (or MMO > 0.6).
    (d) Simple--Simple is defined as a level 1 airplane with a 
VC or VMO <= 250 KCAS (and MMO <= 
0.6), a VSO <= 45 KCAS and approved only for VFR operations.
    (e) Airplanes not certified for aerobatics may be used to perform 
any maneuver incident to normal flying, including--
    (1) Stalls (except whip stalls); and
    (2) Lazy eights, chandelles, and steep turns, in which the angle of 
bank is not more than 60 degrees.
    (f) Airplanes certified for aerobatics may be used to perform 
maneuvers without limitations, other than those limitations necessary 
to avoid damage or injury.


Sec.  23.10  Accepted means of compliance.

    (a) An applicant must show the FAA how it will demonstrate 
compliance with this part using a means of compliance, which may 
include consensus standards, accepted by the Administrator.
    (b) A person requesting acceptance of a means of compliance must 
provide the means of compliance to the FAA in a form and manner 
specified by the Administrator.

Subpart B--Flight

Performance


Sec.  23.100  Weight and center of gravity.

    (a) The applicant must determine weights and centers of gravity 
that provide limits for the safe operation of the airplane.
    (b) The applicant must show compliance with each requirement of 
this subpart at each combination of weight and center of gravity within 
the airplane's range of loading conditions using tolerances acceptable 
to the Administrator.
    (c) The condition of the airplane at the time of determining its 
empty weight and center of gravity must be well defined and easily 
repeatable.


Sec.  23.105  Performance data.

    (a) Unless otherwise prescribed, an airplane must meet the 
performance requirements of this subpart in--
    (1) Still air and standard atmospheric conditions at sea level for 
all airplanes; and
    (2) Ambient atmospheric conditions within the operating envelope 
for--
    (i) Level 1 high-speed and level 2 high-speed airplanes; and
    (ii) Levels 3 and 4 airplanes.
    (b) Unless otherwise prescribed, the applicant must develop the 
performance data required by this subpart for the following conditions:
    (1) Airport altitudes from sea level to 10,000 feet (3,048 meters); 
and
    (2) Temperatures from standard to 30[deg] Celsius above standard or 
the maximum ambient atmospheric temperature at which compliance with 
propulsion cooling requirements in climb is shown, if lower.

[[Page 13518]]

    (c) The procedures used for determining takeoff and landing 
distances must be executable consistently by pilots of average skill in 
atmospheric conditions expected to be encountered in service.
    (d) Performance data determined in accordance with paragraph (b) of 
this section must account for losses due to atmospheric conditions, 
cooling needs, and other demands on power sources.


Sec.  23.110  Stall speed.

    The applicant must determine the airplane stall speed or the 
minimum steady flight speed for each flight configuration used in 
normal operations, including takeoff, climb, cruise, descent, approach, 
and landing. Each determination must account for the most adverse 
conditions for each flight configuration with power set at idle or zero 
thrust.


Sec.  23.115  Takeoff performance.

    (a) The applicant must determine airplane takeoff performance 
accounting for--
    (1) Stall speed safety margins;
    (2) Minimum control speeds; and
    (3) Climb gradients.
    (b) For all airplanes, takeoff performance includes the 
determination of ground roll and initial climb distance to 50 feet (15 
meters) above the takeoff surface.
    (c) For levels 1, 2, and 3 high-speed multiengine airplanes, 
multiengine airplanes with a maximum takeoff weight greater than 12,500 
pounds and level 4 multiengine airplanes, takeoff performance includes 
a determination the following distances after a sudden critical loss of 
thrust:
    (1) Accelerate-stop;
    (2) Ground roll and initial climb to 50 feet (15 meters) above the 
takeoff surface; and
    (3) Net takeoff flight path.


Sec.  23.120  Climb requirements.

    The applicant must demonstrate the following minimum climb 
performance out of ground effect:
    (a) With all engines operating and in the initial climb 
configuration--
    (1) For levels 1 and 2 low speed airplanes, a climb gradient at sea 
level of 8.3 percent for landplanes and 6.7 percent for seaplanes and 
amphibians; and
    (2) For levels 1 and 2 high-speed airplanes and all level 3 
airplanes, a climb gradient at takeoff of 4 percent.
    (b) After a critical loss of thrust on multiengine airplanes--
    (1) For levels 1and 2 low-speed airplanes that do not meet single 
engine crashworthiness requirements, a 1.5 percent climb gradient at a 
pressure altitude of 5,000 feet (1,524 meters) in the cruise 
configuration;
    (2) For levels 1 and 2 high-speed airplanes, and level 3 low-speed 
airplanes, a 1 percent climb gradient at 400 feet (122 meters) above 
the takeoff surface with the landing gear retracted and flaps in the 
takeoff configuration;
    (3) For level 3 high-speed airplanes and all level 4 airplanes, a 2 
percent climb gradient at 400 feet (122 meters) above the takeoff 
surface with the landing gear retracted and flaps in the approach 
configuration;
    (4) At sea level for level 1 and level 2 low-speed airplanes; and
    (5) At the landing surface for all other airplanes.
    (c) For a balked landing, a climb gradient of 3 percent with--
    (1) Takeoff power on each engine;
    (2) Landing gear extended; and
    (3) Flaps in the landing configuration.


Sec.  23.125  Climb information.

    (a) The applicant must determine climb performance--
    (1) For all single engine airplanes;
    (2) For level 3 multiengine airplanes, following a critical loss of 
thrust on takeoff in the initial climb configuration; and
    (3) For all multiengine airplanes, during the enroute phase of 
flight with all engines operating and after a critical loss of thrust 
in the cruise configuration.
    (b) For single engine airplanes, the applicant must determine the 
glide performance of the airplane after a complete loss of thrust.


Sec.  23.130  Landing.

    The applicant must determine the following, for standard 
temperatures at each weight and altitude within the operational limits 
for landing:
    (a) The distance, starting from a height of 50 feet (15 meters) 
above the landing surface, required to land and come to a stop, or for 
water operations, reach a speed of 3 knots.
    (b) The approach and landing speeds, configurations, and 
procedures, which allow a pilot of average skill to meet the landing 
distance consistently and without causing damage or injury.

Flight Characteristics


Sec.  23.200  Controllability.

    (a) The airplane must be controllable and maneuverable, without 
requiring exceptional piloting skill, alertness, or strength, within 
the operating envelope--
    (1) At all loading conditions for which certification is requested;
    (2) During low-speed operations, including stalls;
    (3) With any probable flight control or propulsion system failure; 
and
    (4) During configuration changes.
    (b) The airplane must be able to complete a landing without causing 
damage or serious injury, in the landing configuration at a speed of 
VREF minus 5 knots using the approach gradient equal to the 
steepest used in the landing distance determination.
    (c) For levels 1 and 2 multiengine airplanes that cannot climb 
after a critical loss of thrust, VMC must not exceed 
VS1 or VS0 for all practical weights and 
configurations within the operating envelope of the airplane.
    (d) If the applicant requests certification of an airplane for 
aerobatics, the applicant must demonstrate those aerobatic maneuvers 
for which certification is requested and determine entry speeds.


Sec.  23.205  Trim.

    (a) The airplane must maintain longitudinal, lateral, and 
directional trim under the following conditions:
    (1) For levels 1, 2, and 3 airplanes, in cruise, without further 
force upon, or movement of, the primary flight controls or 
corresponding trim controls by the pilot, or the flight control system.
    (2) For level 4 airplanes in normal operations, without further 
force upon, or movement of, the primary flight controls or 
corresponding trim controls by the pilot, or the flight control system.
    (b) The airplane must maintain longitudinal trim under the 
following conditions:
    (1) Climb.
    (2) Level flight.
    (3) Descent.
    (4) Approach.
    (c) Residual forces must not fatigue or distract the pilot during 
likely emergency operations, including a critical loss of thrust on 
multiengine airplanes.


Sec.  23.210  Stability.

    (a) Airplanes not certified for aerobatics must--
    (1) Have static longitudinal, lateral, and directional stability in 
normal operations;
    (2) Have dynamic short period and combined lateral-directional 
stability in normal operations; and
    (3) Provide stable control force feedback throughout the operating 
envelope.
    (b) No airplane may exhibit any divergent longitudinal stability 
characteristic so unstable as to increase the pilot's workload or 
otherwise endanger the airplane and its occupants.

[[Page 13519]]

Sec.  23.215  Stall characteristics, stall warning, and spins.

    (a) The airplane must have controllable stall characteristics in 
straight flight, turning flight, and accelerated turning flight with a 
clear and distinctive stall warning that provides sufficient margin to 
prevent inadvertent stalling.
    (b) Levels 1 and 2 airplanes and level 3 single-engine airplanes, 
not certified for aerobatics, must not have a tendency to inadvertently 
depart controlled flight.
    (c) Airplanes certified for aerobatics must have controllable stall 
characteristics and the ability to recover within one and one-half 
additional turns after initiation of the first control action from any 
point in a spin, not exceeding six turns or any greater number of turns 
for which certification is requested, while remaining within the 
operating limitations of the airplane.
    (d) Spin characteristics in airplanes certified for aerobatics must 
not result in unrecoverable spins--
    (1) With any use of the flight or engine power controls; or
    (2) Due to pilot disorientation or incapacitation.


Sec.  23.220  Ground and water handling characteristics.

    (a) For airplanes intended for operation on land or water, the 
airplane must have controllable longitudinal and directional handling 
characteristics during taxi, takeoff, and landing operations.
    (b) For airplanes intended for operation on water, the following 
must be established and included in the Airplane Flight Manual (AFM):
    (1) The maximum wave height at which the aircraft demonstrates 
compliance to paragraph (a) of this section. This wave height does not 
constitute an operating limitation.
    (2) Any necessary water handling procedures.


Sec.  23.225  Vibration, buffeting, and high-speed characteristics.

    (a) Vibration and buffeting, for operations up to VD/
MD, must not interfere with the control of the airplane or 
cause fatigue to the flightcrew. Stall warning buffet within these 
limits is allowable.
    (b) For high-speed airplanes and all airplanes with a maximum 
operating altitude greater than 25,000 feet (7,620 meters) pressure 
altitude, there must be no perceptible buffeting in cruise 
configuration at 1g and at any speed up to VMO/
MMO, except stall buffeting.
    (c) For high-speed airplanes, the applicant must determine the 
positive maneuvering load factors at which the onset of perceptible 
buffet occurs in the cruise configuration within the operational 
envelope. Likely inadvertent excursions beyond this boundary must not 
result in structural damage.
    (d) High-speed airplanes must have recovery characteristics that do 
not result in structural damage or loss of control, beginning at any 
likely speed up to VMO/MMO, following--
    (1) An inadvertent speed increase; and
    (2) A high-speed trim upset.


Sec.  23.230  Performance and flight characteristics requirements for 
flight in icing conditions.

    (a) If an applicant requests certification for flight in icing 
conditions as specified in part 1 of appendix C to part 25 of this 
chapter and any additional atmospheric icing conditions for which an 
applicant requests certification, the applicant must demonstrate the 
following:
    (1) Compliance with each requirement of this subpart, except those 
applicable to spins and any that must be demonstrated at speeds in 
excess of--
    (i) 250 knots CAS;
    (ii) VMO or MMO; or
    (iii) A speed at which the applicant demonstrates the airframe will 
be free of ice accretion.
    (2) The stall warning for flight in icing conditions and non-icing 
conditions is the same.
    (b) If an applicant requests certification for flight in icing 
conditions, the applicant must provide a means to detect any icing 
conditions for which certification is not requested and demonstrate the 
aircraft's ability to avoid or exit those conditions.
    (c) The applicant must develop an operating limitation to prohibit 
intentional flight, including takeoff and landing, into icing 
conditions for which the airplane is not certified to operate.

Subpart C--Structures


Sec.  23.300  Structural design envelope.

    The applicant must determine the structural design envelope, which 
describes the range and limits of airplane design and operational 
parameters for which the applicant will show compliance with the 
requirements of this subpart. The applicant must account for all 
airplane design and operational parameters that affect structural 
loads, strength, durability, and aeroelasticity, including:
    (a) Structural design airspeeds and Mach numbers, including--
    (1) The design maneuvering airspeed, VA, which may be no 
less than the airspeed at which the airplane will stall at the maximum 
design maneuvering load factor;
    (2) The design cruising airspeed, VC or MC, 
which may be no less than the maximum speed expected in normal 
operations;
    (3) The design dive airspeed, VD or MD, which 
is the airspeed that will not be exceeded by inadvertent airspeed 
increases when operating at VC or MC;
    (4) Any other design airspeed limitations required for the 
operation of high lift devices, landing gear, and other equipment or 
devices; and
    (5) For level 4 airplanes, a rough air penetration speed, 
VB.
    (b) Design maneuvering load factors not less than those, which 
service history shows, may occur within the structural design envelope.
    (c) Inertial properties including weight, center of gravity, and 
mass moments of inertia, accounting for--
    (1) All weights from the airplane empty weight to the maximum 
weight; and
    (2) The weight and distribution of occupants, payload, and fuel.
    (d) Range of motion for control surfaces, high lift devices, or 
other moveable surfaces, including tolerances.
    (e) All altitudes up to the maximum altitude.


Sec.  23.305  Interaction of systems and structures.

    For airplanes equipped with systems that affect structural 
performance, either directly or as a result of failure or malfunction, 
the applicant must account for the influence and failure conditions of 
these systems when showing compliance with the requirements of this 
subpart.

Structural Loads


Sec.  23.310  Structural design loads.

    The applicant must:
    (a) Determine structural design loads resulting from any externally 
or internally applied pressure, force, or moment which may occur in 
flight, ground and water operations, ground and water handling, and 
while the airplane is parked or moored.
    (b) Determine the loads required by paragraph (a) of this section 
at all critical combinations of parameters, on and within the 
boundaries of the structural design envelope.
    (c) The magnitude and distribution of these loads must be based on 
physical principles and may be no less than service history shows will 
occur within the structural design envelope.


Sec.  23.315  Flight load conditions.

    The applicant must determine the structural design loads resulting 
from the following flight conditions:

[[Page 13520]]

    (a) Vertical and horizontal atmospheric gusts where the magnitude 
and gradient of these gusts are based on measured gust statistics.
    (b) Symmetric and asymmetric maneuvers.
    (c) For canted lifting surfaces, vertical and horizontal loads 
acting simultaneously resulting from gust and maneuver conditions.
    (d) For multiengine airplanes, failure of the powerplant unit which 
results in the most severe structural loads.


Sec.  23.320  Ground and water load conditions.

    The applicant must determine the structural design loads resulting 
from the following ground and water operations:
    (a) For airplanes intended for operation on land--taxi, takeoff, 
landing, and ground handling conditions occurring in normal and adverse 
attitudes and configurations.
    (b) For airplanes intended for operation on water--taxi, takeoff, 
landing, and water handling conditions occurring in normal and adverse 
attitudes and configurations in the most severe sea conditions expected 
in operation.
    (c) Jacking and towing conditions.


Sec.  23.325  Component loading conditions.

    The applicant must determine the structural design loads acting on:
    (a) Each engine mount and its supporting structure resulting from 
engine operation combined with gusts and maneuvers.
    (b) Each flight control and high lift surface, their associated 
system and supporting structure resulting from--
    (1) The inertia of each surface and mass balance attachment;
    (2) Gusts and maneuvers;
    (3) Pilot or automated system inputs;
    (4) System induced conditions, including jamming and friction; and
    (5) Ground operations, including downwind taxi and ground gusts.
    (c) A pressurized cabin resulting from the pressurization 
differential--
    (1) From zero up to the maximum relief valve setting combined with 
gust and maneuver loads;
    (2) From zero up to the maximum relief valve setting combined with 
ground and water loads if the airplane may land with the cabin 
pressurized; and
    (3) At the maximum relief valve setting multiplied by 1.33, 
omitting all other loads.


Sec.  23.330  Limit and ultimate loads.

    Unless special or other factors of safety are necessary to meet the 
requirements of this subpart, the applicant must determine--
    (a) The limit loads, which are equal to the structural design 
loads; and
    (b) The ultimate loads, which are equal to the limit loads 
multiplied by a 1.5 factor of safety.

Structural Performance


Sec.  23.400  Structural strength.

    The applicant must demonstrate that the structure will support:
    (a) Limit loads without--
    (1) Interference with the operation of the airplane; and
    (2) Detrimental permanent deformation.
    (b) Ultimate loads.


Sec.  23.405  Structural durability.

    (a) The applicant must develop and implement procedures to prevent 
structural failures due to foreseeable causes of strength degradation, 
which could result in serious or fatal injuries, loss of the airplane, 
or extended periods of operation with reduced safety margins. The 
Instructions for Continued Airworthiness must include procedures 
developed under this section.
    (b) If a pressurized cabin has two or more compartments separated 
by bulkheads or a floor, the applicant must design the structure for a 
sudden release of pressure in any compartment that has a door or 
window, considering failure of the largest door or window opening in 
the compartment.
    (c) For airplanes with maximum operating altitude greater than 
41,000 feet, the procedures developed for compliance to paragraph (a) 
of this section must be capable of detecting damage to the pressurized 
cabin structure before the damage could result in rapid decompression 
that would result in serious or fatal injuries.
    (d) The airplane must be capable of continued safe flight and 
landing with structural damage caused by high-energy fragments from an 
uncontained engine or rotating machinery failure.


Sec.  23.410  Aeroelasticity.

    (a) The airplane must be free from flutter, control reversal, and 
divergence--
    (1) At all speeds within and sufficiently beyond the structural 
design envelope;
    (2) For any configuration and condition of operation;
    (3) Accounting for critical degrees of freedom; and
    (4) Accounting for any critical failures or malfunctions.
    (b) The applicant must establish and account for tolerances for all 
quantities that affect flutter.

Design


Sec.  23.500  Structural design.

    (a) The applicant must design each part, article, and assembly for 
the expected operating conditions of the airplane.
    (b) Design data must adequately define the part, article, or 
assembly configuration, its design features, and any materials and 
processes used.
    (c) The applicant must determine the suitability of each design 
detail and part having an important bearing on safety in operations.
    (d) The control system must be free from jamming, excessive 
friction, and excessive deflection when--
    (1) The control system and its supporting structure are subjected 
to loads corresponding to the limit airloads;
    (2) The primary controls are subjected to the lesser of the limit 
airloads or limit pilot forces; and
    (3) The secondary controls are subjected to loads not less than 
those corresponding to maximum pilot effort.


Sec.  23.505  Protection of structure.

    (a) The applicant must protect each part of the airplane, including 
small parts such as fasteners, against deterioration or loss of 
strength due to any cause likely to occur in the expected operational 
environment.
    (b) Each part of the airplane must have adequate provisions for 
ventilation and drainage.
    (c) For each part that requires maintenance, preventive 
maintenance, or servicing, the applicant must incorporate a means into 
the aircraft design to allow such actions to be accomplished.


Sec.  23.510  Materials and processes.

    (a) The applicant must determine the suitability and durability of 
materials used for parts, articles, and assemblies, the failure of 
which could prevent continued safe flight and landing. The applicant 
must account for the effects of likely environmental conditions 
expected in service.
    (b) The methods and processes of fabrication and assembly used must 
produce consistently sound structures. If a fabrication process 
requires close control to reach this objective, the applicant must 
perform the process under an approved process specification.
    (c) Except as provided in paragraphs (f) and (g) of this section, 
the applicant must select design values that ensure material strength 
with probabilities that account for the criticality of the structural 
element. Design values must

[[Page 13521]]

account for the probability of structural failure due to material 
variability.
    (d) If material strength properties are required, a determination 
of those properties must be based on sufficient tests of material 
meeting specifications to establish design values on a statistical 
basis.
    (e) If thermal effects are significant on an essential component or 
structure under normal operating conditions, the applicant must 
determine those effects on allowable stresses used for design.
    (f) Design values, greater than the minimums specified by this 
section, may be used, where only guaranteed minimum values are normally 
allowed, if a specimen of each individual item is tested before use to 
determine that the actual strength properties of that particular item 
will equal or exceed those used in the design.
    (g) An applicant may use other material design values if approved 
by the Administrator.


Sec.  23.515  Special factors of safety.

    (a) The applicant must determine a special factor of safety for any 
critical design value that is--
    (1) Uncertain;
    (2) Used for a part, article, or assembly that is likely to 
deteriorate in service before normal replacement; or
    (3) Subject to appreciable variability because of uncertainties in 
manufacturing processes or inspection methods.
    (b) The applicant must determine a special factor of safety using 
quality controls and specifications that account for each--
    (1) Structural application;
    (2) Inspection method;
    (3) Structural test requirement;
    (4) Sampling percentage; and
    (5) Process and material control.
    (c) The applicant must apply any special factor of safety in the 
design for each part of the structure by multiplying each limit load 
and ultimate load by the special factor of safety.

Structural Occupant Protection


Sec.  23.600  Emergency conditions.

    (a) The airplane, even when damaged in an emergency landing, must 
protect each occupant against injury that would preclude egress when--
    (1) Properly using safety equipment and features provided for in 
the design;
    (2) The occupant experiences ultimate static inertia loads likely 
to occur in an emergency landing; and
    (3) Items of mass, including engines or auxiliary power units 
(APUs), within or aft of the cabin, that could injure an occupant, 
experience ultimate static inertia loads likely to occur in an 
emergency landing.
    (b) The emergency landing conditions specified in paragraph (a) of 
this section, must--
    (1) Include dynamic conditions that are likely to occur with an 
impact at stall speed, accounting for variations in aircraft mass, 
flight path angle, flight pitch angle, yaw, and airplane configuration, 
including likely failure conditions at impact; and
    (2) Not exceed established human injury criteria for human 
tolerance due to restraint or contact with objects in the airplane.
    (c) The airplane must have seating and restraints for all 
occupants. The airplane seating, restraints, and cabin interior must 
account for likely flight and emergency landing conditions.
    (d) Each occupant restraint system must consist of a seat, a method 
to restrain the occupant's pelvis and torso, and a single action 
restraint release. For all flight and ground loads during normal 
operation and any emergency landing conditions, the restraint system 
must perform its intended function and not create a hazard that could 
cause a secondary injury to an occupant. The restraint system must not 
prevent occupant egress or interfere with the operation of the airplane 
when not in use.
    (e) Each baggage and cargo compartment must--
    (1) Be designed for its maximum weight of contents and for the 
critical load distributions at the maximum load factors corresponding 
to the flight and ground load conditions determined under this part;
    (2) Have a means to prevent the contents of the compartment from 
becoming a hazard by impacting occupants or shifting; and
    (3) Protect any controls, wiring, lines, equipment, or accessories 
whose damage or failure would affect operations.

Subpart D--Design and Construction


Sec.  23.700  Flight control systems.

    (a) The applicant must design airplane flight control systems to:
    (1) Prevent major, hazardous, and catastrophic hazards, including--
    (i) Failure;
    (ii) Operational hazards;
    (iii) Flutter;
    (iv) Asymmetry; and
    (v) Misconfiguration.
    (2) Operate easily, smoothly, and positively enough to allow normal 
operation.
    (b) The applicant must design trim systems to:
    (1) Prevent inadvertent, incorrect, or abrupt trim operation.
    (2) Provide a means to indicate--
    (i) The direction of trim control movement relative to airplane 
motion;
    (ii) The trim position with respect to the trim range;
    (iii) The neutral position for lateral and directional trim; and
    (iv) For all airplanes, except simple airplanes, the range for 
takeoff for all applicant requested center of gravity ranges and 
configurations.
    (3) Except for simple airplanes, provide control for continued safe 
flight and landing when any one connecting or transmitting element in 
the primary flight control system fails.
    (4) Limit the range of travel to allow safe flight and landing, if 
an adjustable stabilizer is used.
    (c) For an airplane equipped with an artificial stall barrier 
system, the system must--
    (1) Prevent uncommanded control or thrust action; and
    (2) Provide for a preflight check.
    (d) For level 3 high-speed and all level 4 airplanes, an applicant 
must install a takeoff warning system on the airplane unless the 
applicant demonstrates the airplane, for each configuration, can 
takeoff at the limits of the trim and flap ranges.


Sec.  23.705  Landing gear systems.

    (a) For airplanes with retractable landing gear:
    (1) The landing gear and retracting mechanism, including the wheel 
well doors, must be able to withstand operational and flight loads.
    (2) The airplane must have--
    (i) A positive means to keep the landing gear extended;
    (ii) A secondary means of extension for landing gear that cannot be 
extended using the primary means;
    (iii) A means to inform the pilot that each landing gear is secured 
in the extended and retracted positions; and
    (iv) Except for airplanes intended for operation on water, a 
warning to the pilot if the thrust and configuration is selected for 
landing and the landing gear is not fully extended and locked.
    (3) If the landing gear bay is used as the location for equipment 
other than the landing gear, that equipment must be designed and 
installed to avoid damage from tire burst and from items that may enter 
the landing gear bay.
    (b) The design of each landing gear wheel, tire, and ski must 
account for critical loads, including those experienced during landing 
and rejected takeoff.
    (c) A reliable means of stopping the airplane must provide kinetic 
energy absorption within the airplane's design specifications for 
landing.

[[Page 13522]]

    (d) For levels 3 and 4 multiengine airplanes, the braking system 
must provide kinetic energy absorption within the airplane's design 
specifications for rejected takeoff.


Sec.  23.710  Buoyancy for seaplanes and amphibians.

    Airplanes intended for operations on water, must--
    (a) Provide buoyancy of 80 percent in excess of the buoyancy 
required to support the maximum weight of the airplane in fresh water; 
and
    (b) Have sufficient watertight compartments so the airplane will 
stay afloat at rest in calm water without capsizing if any two 
compartments of any main float or hull are flooded.
Occupant System Design Protection


Sec.  23.750  Means of egress and emergency exits.

    (a) The airplane cabin exit design must provide for evacuation of 
the airplane within 90 seconds in conditions likely to occur following 
an emergency landing. Likely conditions exclude ditching for all but 
levels 3 and 4 multiengine airplanes.
    (b) Each exit must have a means to be opened from both inside and 
outside the airplane, when the internal locking mechanism is in the 
locked and unlocked position. The means of opening must be simple, 
obvious, and marked inside and outside the airplane.
    (c) Airplane evacuation paths must protect occupants from serious 
injury from the propulsion system.
    (d) Each exit must not be obstructed by a seat or seat back, unless 
the seat or seat back can be easily moved in one action to clear the 
exit.
    (e) Airplanes certified for aerobatics must have a means to egress 
the airplane in flight.
    (f) Doors, canopies, and exits must be protected from opening 
inadvertently in flight.


Sec.  23.755  Occupant physical environment.

    (a) The applicant must design the airplane to--
    (1) Allow clear communication between the flightcrew and 
passengers;
    (2) Provide a clear, sufficiently undistorted external view to 
enable the flightcrew to perform any maneuvers within the operating 
limitations of the airplane;
    (3) Protect the pilot from serious injury due to high energy 
rotating failures in systems and equipment; and
    (4) Protect the occupants from serious injury due to damage to 
windshields, windows, and canopies.
    (b) For level 4 airplanes, each windshield and its supporting 
structure directly in front of the pilot must--
    (1) Withstand, without penetration, the impact equivalent to a two-
pound bird when the velocity of the airplane is equal to the airplane's 
maximum approach flap speed; and
    (2) Allow for continued safe flight and landing after the loss of 
vision through any one panel.
    (c) The airplane must provide each occupant with air at a 
breathable pressure, free of hazardous concentrations of gases and 
vapors, during normal operations and likely failures.
    (d) If an oxygen system is installed in the airplane, it must 
include--
    (1) A means to allow the flightcrew to determine the quantity of 
oxygen available in each source of supply on the ground and in flight;
    (2) A means to determine whether oxygen is being delivered; and
    (3) A means to permit the flightcrew to turn on and shut off the 
oxygen supply at any high-pressure source in flight.
    (e) If a pressurization system is installed in the airplane, it 
must include--
    (1) A warning if an unsafe condition exists; and
    (2) A pressurization system test.
Fire and High Energy Protection


Sec.  23.800  Fire protection outside designated fire zones.

    Outside designated fire zones:
    (a) The following materials must be self-extinguishing--
    (1) Insulation on electrical wire and electrical cable;
    (2) For levels 1, 2, and 3 airplanes, materials in the baggage and 
cargo compartments inaccessible in flight; and
    (3) For level 4 airplanes, materials in the cockpit, cabin, 
baggage, and cargo compartments.
    (b) The following materials must be flame resistant--
    (1) For levels 1, 2 and 3 airplanes, materials in each compartment 
accessible in flight; and
    (2) Any electrical cable installation that would overheat in the 
event of circuit overload or fault.
    (c) Thermal acoustic materials, if installed, must not be a flame 
propagation hazard.
    (d) Sources of heat that are capable of igniting adjacent objects 
must be shielded and insulated to prevent such ignition.
    (e) For level 4 airplanes, each baggage and cargo compartment 
must--
    (1) Be located where a fire would be visible to the pilots, or 
equipped with a fire detection system and warning system; and
    (2) Be accessible for the manual extinguishing of a fire, have a 
built-in fire extinguishing system, or be constructed and sealed to 
contain any fire within the compartment.
    (f) There must be a means to extinguish any fire in the cabin such 
that--
    (1) The pilot, while seated, can easily access the fire 
extinguishing means; and
    (2) For levels 3 and 4 airplanes, passengers have a fire 
extinguishing means available within the passenger compartment.
    (g) Each area where flammable fluids or vapors might escape by 
leakage of a fluid system must--
    (1) Be defined; and
    (2) Have a means to make fluid and vapor ignition, and the 
resultant hazard, if ignition occurs, improbable.
    (h) Combustion heater installations must be protected from 
uncontained fire.


Sec.  23.805  Fire protection in designated fire zones.

    Inside designated fire zones:
    (a) Flight controls, engine mounts, and other flight structures 
within or adjacent to those zones must be capable of withstanding the 
effects of a fire.
    (b) Engines must remain attached to the airplane in the event of a 
fire or electrical arcing.
    (c) Terminals, equipment, and electrical cables used during 
emergency procedures must be fire-resistant.


Sec.  23.810  Lightning protection of structure.

    (a) For airplanes approved for instrument flight rules, no 
structural failure preventing continued safe flight and landing may 
occur from exposure to the direct effects of lightning.
    (b) Airplanes approved only for visual flight rules must achieve 
lightning protection by following FAA accepted design practices.

Subpart E--Powerplant


Sec.  23.900  Powerplant installation.

    (a) For the purpose of this subpart, the airplane powerplant 
installation must include each component necessary for propulsion, 
affects propulsion safety, or provides auxiliary power to the airplane.
    (b) The applicant must construct and arrange each powerplant 
installation to account for likely hazards in operation and 
maintenance.
    (c) Except for simple airplanes, each aircraft power unit must be 
type certificated.


Sec.  23.905  Propeller installation.

    (a) Except for simple airplanes, each propeller must be type 
certificated.

[[Page 13523]]

    (b) Each pusher propeller must be marked so that it is conspicuous 
under daylight conditions.
    (c) Each propeller installation must account for vibration and 
fatigue.


Sec.  23.910  Powerplant installation hazard assessment.

    The applicant must assess each powerplant separately and in 
relation to other airplane systems and installations to show that a 
failure of any powerplant system component or accessory will not--
    (a) Prevent continued safe flight and landing;
    (b) Cause serious injury that may be avoided; and
    (c) Require immediate action by crewmembers for continued operation 
of any remaining powerplant system.


Sec.  23.915  Automatic power control systems.

    A power or thrust augmentation system that automatically controls 
the power or thrust on the operating powerplant, must--
    (a) Provide indication to the flightcrew when the system is 
operating;
    (b) Provide a means for the pilot to deactivate the automatic 
function; and
    (c) Prevent inadvertent deactivation.


Sec.  23.920  Reversing systems.

    The airplane must be capable of continued safe flight and landing 
under any available reversing system setting.


Sec.  23.925  Powerplant operational characteristics.

    (a) The powerplant must operate at any negative acceleration that 
may occur during normal and emergency operation, within the airplane 
operating limitations.
    (b) The pilot must have the capability to stop and restart the 
powerplant in flight.
    (c) The airplane must have an independent power source for 
restarting each powerplant following an in-flight shutdown.


Sec.  23.930  Fuel system

    (a) Each fuel system must--
    (1) Provide an independent fuel supply to each powerplant in at 
least one configuration;
    (2) Avoid ignition from unplanned sources;
    (3) Provide the fuel required to achieve maximum power or thrust 
plus a margin for likely variables, in all temperature and altitude 
conditions within the airplane operating envelope;
    (4) Provide a means to remove the fuel from the airplane;
    (5) Be capable of retaining fuel when subject to inertia loads 
under expected operating conditions; and
    (6) Prevent hazardous contamination of the fuel supply.
    (b) Each fuel storage system must--
    (1) Withstand the loads and pressures under expected operating 
conditions;
    (2) Provide a means to prevent loss of fuel during any maneuver 
under operating conditions for which certification is requested;
    (3) Prevent discharge when transferring fuel;
    (4) Provide fuel for at least one-half hour of operation at maximum 
continuous power or thrust; and
    (5) Be capable of jettisoning fuel if required for landing.
    (c) If a pressure refueling system is installed, it must have a 
means to--
    (1) Prevent the escape of hazardous quantities of fuel;
    (2) Automatically shut-off before exceeding the maximum fuel 
quantity of the airplane; and
    (3) Provide an indication of a failure at the fueling station.


Sec.  23.935  Powerplant induction and exhaust systems.

    The air induction system for each power unit and its accessories 
must--
    (a) Supply the air required by that power unit and its accessories 
under expected operating conditions; and
    (b) Provide a means to discharge potential harmful material.


Sec.  23.940  Powerplant ice protection.

    (a) The airplane design must prevent foreseeable accumulation of 
ice or snow that adversely affects powerplant operation.
    (b) The powerplant design must prevent any accumulation of ice or 
snow that adversely affects powerplant operation, in those icing 
conditions for which certification is requested.


Sec.  23.1000  Powerplant fire protection.

    (a) A powerplant may only be installed in a designated fire zone.
    (b) Each component, line, and fitting carrying flammable fluids, 
gases, or air subject to fire conditions must be fire resistant, except 
components storing concentrated flammable material must be fireproof or 
enclosed by a fireproof shield.
    (c) The applicant must provide a means to shut off fuel or 
flammable material for each powerplant that must--
    (1) Not restrict fuel to remaining units; and
    (2) Prevent inadvertent operation.
    (d) For levels 3 and 4 airplanes with a powerplant located outside 
the pilot's view that uses combustible fuel, the applicant must install 
a fire extinguishing system.
    (e) For levels 3 and 4 airplanes, the applicant must install a fire 
detection system in each designated fire zone.
    (f) Each fire detection system must provide a means to alert the 
flightcrew in the event of a detection of fire or failure of the 
system.
    (g) There must be a means to check the fire detection system in 
flight.

Subpart F--Equipment


Sec.  23.1300  Airplane level systems requirements.

    (a) The equipment and systems required for an airplane to operate 
safely in the kinds of operations for which certification is requested 
(Day VFR, Night VFR, IFR) must be designed and installed to--
    (1) Meet the level of safety applicable to the certification and 
performance level of the airplane; and
    (2) Perform their intended function throughout the operating and 
environmental limits specified by the applicant.
    (b) Non[hyphen]required airplane equipment and systems, considered 
separately and in relation to other systems, must be designed and 
installed so their operation or failure does not have an adverse effect 
on the airplane or its occupants.


Sec.  23.1305  Function and installation.

    (a) Each item of installed equipment must--
    (1) Perform its intended function;
    (2) Be installed according to limitations specified for that 
equipment; and
    (3) Be labeled, if applicable, as to its identification, function 
or operating limitations, or any combination of these factors.
    (b) There must be a discernable means of providing system operating 
parameters required to operate the airplane, including warnings, 
cautions, and normal indications to the responsible crewmember.
    (c) Information concerning an unsafe system operating condition 
must be provided in a timely manner to the crewmember responsible for 
taking corrective action. Presentation of this information must be 
clear enough to avoid likely crewmember errors.


Sec.  23.1310  Flight, navigation, and powerplant instruments.

    (a) Installed systems must provide the flightcrew member who sets 
or monitors flight parameters for the flight, navigation, and 
powerplant the information necessary to do so during each phase of 
flight. This information must include--

[[Page 13524]]

    (1) Parameters and trends, as needed for normal, abnormal, and 
emergency operation; and
    (2) Limitations, unless the applicant shows each limitation will 
not be exceeded in all intended operations.
    (b) Indication systems that integrate the display of flight or 
powerplant parameters to operate the airplane or are required by the 
operating rules of this chapter must--
    (1) Not inhibit the primary display of flight or powerplant 
parameters needed by any flightcrew member in any normal mode of 
operation; and
    (2) In combination with other systems, be designed and installed so 
information essential for continued safe flight and landing will be 
available to the flightcrew in a timely manner after any single failure 
or probable combination of failures.


Sec.  23.1315  Equipment, systems, and installations.

    For any airplane system or equipment whose failure or abnormal 
operation has not been specifically addressed by another requirement in 
this part, the applicant must:
    (a) Examine the design and installation of airplane systems and 
equipment, separately and in relation to other airplane systems and 
equipment to determine--
    (1) If a failure would prevent continued safe flight and landing; 
and
    (2) If any other failure would significantly reduce the capability 
of the airplane or the ability of the flightcrew to cope with adverse 
operating conditions.
    (b) Design and install each system and equipment, examined 
separately and in relation to other airplane systems and equipment, 
such that--
    (1) Each catastrophic failure condition is extremely improbable;
    (2) Each hazardous failure condition is extremely remote; and
    (3) Each major failure condition is remote.


Sec.  23.1320  Electrical and electronic system lightning protection.

    For an airplane approved for IFR operations:
    (a) Each electrical or electronic system that performs a function, 
the failure of which would prevent the continued safe flight and 
landing of the airplane, must be designed and installed such that--
    (1) The airplane system level function continues to perform during 
and after the time the airplane is exposed to lightning; and
    (2) The system automatically recovers normal operation of that 
function in a timely manner after the airplane is exposed to lightning 
unless the system's recovery conflicts with other operational or 
functional requirements of the system.
    (b) Each electrical and electronic system that performs a function, 
the failure of which would reduce the capability of the airplane or the 
ability of the flightcrew to respond to an adverse operating condition, 
must be designed and installed such that the function recovers normal 
operation in a timely manner after the airplane is exposed to 
lightning.


Sec.  23.1325  High-intensity Radiated Fields (HIRF) protection.

    (a) Electrical and electronic systems that perform a function, the 
failure of which would prevent the continued safe flight and landing of 
the airplane, must be designed and installed such that--
    (1) The airplane system level function is not adversely affected 
during and after the time the airplane is exposed to the HIRF 
environment; and
    (2) The system automatically recovers normal operation of that 
function in a timely manner after the airplane is exposed to the HIRF 
environment, unless the system's recovery conflicts with other 
operational or functional requirements of the system.
    (b) For airplanes approved for IFR operations, the applicant must 
design and install each electrical and electronic system that performs 
a function, the failure of which would reduce the capability of the 
airplane or the ability of the flightcrew to respond to an adverse 
operating condition, so the function recovers normal operation in a 
timely manner after the airplane is exposed to the HIRF environment.


Sec.  23.1330  System power generation, storage, and distribution.

    The power generation, storage, and distribution for any system must 
be designed and installed to--
    (a) Supply the power required for operation of connected loads 
during all likely operating conditions;
    (b) Ensure no single failure or malfunction will prevent the system 
from supplying the essential loads required for continued safe flight 
and landing; and
    (c) Have enough capacity, if the primary source fails, to supply 
essential loads, including non-continuous essential loads for the time 
needed to complete the function, for--
    (1) At least 30 minutes for airplanes certificated with a maximum 
altitude of 25,000 feet (7,620 meters) or less; and
    (2) At least 60 minutes for airplanes certificated with a maximum 
altitude over 25,000 feet (7,620 meters).


Sec.  23.1335  External and cockpit lighting.

    (a) The applicant must design and install all lights to prevent 
adverse effects on the performance of flightcrew duties.
    (b) Any position and anti-collision lights, if required by part 91 
of this chapter, must have the intensities, flash rate, colors, fields 
of coverage, and other characteristics to provide sufficient time for 
another aircraft to avoid a collision.
    (c) Any position lights, if required by part 91 of this chapter, 
must include a red light on the left side of the airplane, a green 
light on the right side of the airplane, spaced laterally as far apart 
as space allows, and a white light facing aft, located on an aft 
portion of the airplane or on the wing tips.
    (d) The applicant must design and install taxi and landing lights 
so they provide sufficient light for night operations.
    (e) For seaplanes or amphibian airplanes, riding lights must 
provide a white light visible in clear atmospheric conditions.


Sec.  23.1400  Safety equipment.

    Safety and survival equipment, required by the operating rules of 
this chapter, must be reliable, readily accessible, easily 
identifiable, and clearly marked to identify its method of operation.


Sec.  23.1405  Flight in icing conditions.

    (a) If an applicant requests certification for flight in icing 
conditions, the applicant must demonstrate that--
    (1) The ice protection system provides for safe operation; and
    (2) The airplane is protected from stalling when the autopilot is 
operating in a vertical mode.
    (b) The demonstration specified in paragraph (a) of this section, 
must be conducted in atmospheric icing conditions specified in part 1 
of appendix C to part 25 of this chapter, and any additional icing 
conditions for which certification is requested.


Sec.  23.1410  Pressurized systems elements.

    (a) The minimum burst pressure of hydraulic systems must be at 
least 2.5 times the design operating pressure. The proof pressure must 
be at least 1.5 times the maximum operating pressure.
    (b) On multiengine airplanes, engine driven accessories essential 
to safe operation must be distributed among multiple engines.
    (c) The minimum burst pressure of cabin pressurization system 
elements must be at least 2.0 times, and proof pressure must be at 
least 1.5 times, the maximum normal operating pressure.

[[Page 13525]]

    (d) The minimum burst pressure of pneumatic system elements must be 
at least 3.0 times, and proof pressure must be at least 1.5 times, the 
maximum normal operating pressure.
    (e) Other pressurized system elements must have pressure margins 
that take into account system design and operating conditions.


Sec.  23.1457  Cockpit voice recorders.

    (a) Each cockpit voice recorder required by the operating rules of 
this chapter must be approved and must be installed so that it will 
record the following:
    (1) Voice communications transmitted from or received in the 
airplane by radio.
    (2) Voice communications of flightcrew members on the flight deck.
    (3) Voice communications of flightcrew members on the flight deck, 
using the airplane's interphone system.
    (4) Voice or audio signals identifying navigation or approach aids 
introduced into a headset or speaker.
    (5) Voice communications of flightcrew members using the passenger 
loudspeaker system, if there is such a system and if the fourth channel 
is available in accordance with the requirements of paragraph 
(c)(4)(ii) of this section.
    (6) If datalink communication equipment is installed, all datalink 
communications, using an approved data message set. Datalink messages 
must be recorded as the output signal from the communications unit that 
translates the signal into usable data.
    (b) The recording requirements of paragraph (a)(2) of this section 
must be met by installing a cockpit-mounted area microphone, located in 
the best position for recording voice communications originating at the 
first and second pilot stations and voice communications of other 
crewmembers on the flight deck when directed to those stations. The 
microphone must be so located and, if necessary, the preamplifiers and 
filters of the recorder must be so adjusted or supplemented, so that 
the intelligibility of the recorded communications is as high as 
practicable when recorded under flight cockpit noise conditions and 
played back. Repeated aural or visual playback of the record may be 
used in evaluating intelligibility.
    (c) Each cockpit voice recorder must be installed so that the part 
of the communication or audio signals specified in paragraph (a) of 
this section obtained from each of the following sources is recorded on 
a separate channel:
    (1) For the first channel, from each boom, mask, or handheld 
microphone, headset, or speaker used at the first pilot station.
    (2) For the second channel from each boom, mask, or handheld 
microphone, headset, or speaker used at the second pilot station.
    (3) For the third channel--from the cockpit-mounted area 
microphone.
    (4) For the fourth channel from:
    (i) Each boom, mask, or handheld microphone, headset, or speaker 
used at the station for the third and fourth crewmembers.
    (ii) If the stations specified in paragraph (c)(4)(i) of this 
section are not required or if the signal at such a station is picked 
up by another channel, each microphone on the flight deck that is used 
with the passenger loudspeaker system, if its signals are not picked up 
by another channel.
    (5) And that as far as is practicable all sounds received by the 
microphone listed in paragraphs (c)(1), (2), and (4) of this section 
must be recorded without interruption irrespective of the position of 
the interphone-transmitter key switch. The design shall ensure that 
sidetone for the flightcrew is produced only when the interphone, 
public address system, or radio transmitters are in use.
    (d) Each cockpit voice recorder must be installed so that:
    (1) (i) It receives its electrical power from the bus that provides 
the maximum reliability for operation of the cockpit voice recorder 
without jeopardizing service to essential or emergency loads.
    (ii) It remains powered for as long as possible without 
jeopardizing emergency operation of the airplane.
    (2) There is an automatic means to simultaneously stop the recorder 
and prevent each erasure feature from functioning, within 10 minutes 
after crash impact.
    (3) There is an aural or visual means for preflight checking of the 
recorder for proper operation.
    (4) Any single electrical failure external to the recorder does not 
disable both the cockpit voice recorder and the flight data recorder.
    (5) It has an independent power source--
    (i) That provides 101 minutes of electrical power to 
operate both the cockpit voice recorder and cockpit-mounted area 
microphone;
    (ii) That is located as close as practicable to the cockpit voice 
recorder; and
    (iii) To which the cockpit voice recorder and cockpit-mounted area 
microphone are switched automatically in the event that all other power 
to the cockpit voice recorder is interrupted either by normal shutdown 
or by any other loss of power to the electrical power bus.
    (6) It is in a separate container from the flight data recorder 
when both are required. If used to comply with only the cockpit voice 
recorder requirements, a combination unit may be installed.
    (e) The recorder container must be located and mounted to minimize 
the probability of rupture of the container as a result of crash impact 
and consequent heat damage to the recorder from fire.
    (1) Except as provided in paragraph (e)(2) of this section, the 
recorder container must be located as far aft as practicable, but need 
not be outside of the pressurized compartment, and may not be located 
where aft-mounted engines may crush the container during impact.
    (2) If two separate combination digital flight data recorder and 
cockpit voice recorder units are installed instead of one cockpit voice 
recorder and one digital flight data recorder, the combination unit 
that is installed to comply with the cockpit voice recorder 
requirements may be located near the cockpit.
    (f) If the cockpit voice recorder has a bulk erasure device, the 
installation must be designed to minimize the probability of 
inadvertent operation and actuation of the device during crash impact.
    (g) Each recorder container must--
    (1) Be either bright orange or bright yellow;
    (2) Have reflective tape affixed to its external surface to 
facilitate its location under water; and
    (3) Have an underwater locating device, when required by the 
operating rules of this chapter, on or adjacent to the container, which 
is secured in such manner that they are not likely to be separated 
during crash impact.


Sec.  23.1459  Flight data recorders.

    (a) Each flight recorder required by the operating rules of this 
chapter must be installed so that--
    (1) It is supplied with airspeed, altitude, and directional data 
obtained from sources that meet the aircraft level system requirements 
of Sec.  23.1300 and the functionality specified in Sec.  23.1305;
    (2) The vertical acceleration sensor is rigidly attached, and 
located longitudinally either within the approved center of gravity 
limits of the airplane, or at a distance forward or aft of these limits 
that does not exceed 25 percent of the airplane's mean aerodynamic 
chord;
    (3)(i) It receives its electrical power from the bus that provides 
the

[[Page 13526]]

maximum reliability for operation of the flight data recorder without 
jeopardizing service to essential or emergency loads;
    (ii) It remains powered for as long as possible without 
jeopardizing emergency operation of the airplane;
    (4) There is an aural or visual means for preflight checking of the 
recorder for proper recording of data in the storage medium;
    (5) Except for recorders powered solely by the engine-driven 
electrical generator system, there is an automatic means to 
simultaneously stop a recorder that has a data erasure feature and 
prevent each erasure feature from functioning, within 10 minutes after 
crash impact;
    (6) Any single electrical failure external to the recorder does not 
disable both the cockpit voice recorder and the flight data recorder; 
and
    (7) It is in a separate container from the cockpit voice recorder 
when both are required. If used to comply with only the flight data 
recorder requirements, a combination unit may be installed. If a 
combination unit is installed as a cockpit voice recorder to comply 
with Sec.  23.1457(e)(2), a combination unit must be used to comply 
with this flight data recorder requirement.
    (b) Each non-ejectable record container must be located and mounted 
so as to minimize the probability of container rupture resulting from 
crash impact and subsequent damage to the record from fire. In meeting 
this requirement, the record container must be located as far aft as 
practicable, but need not be aft of the pressurized compartment, and 
may not be where aft-mounted engines may crush the container upon 
impact.
    (c) A correlation must be established between the flight recorder 
readings of airspeed, altitude, and heading and the corresponding 
readings (taking into account correction factors) of the first pilot's 
instruments. The correlation must cover the airspeed range over which 
the airplane is to be operated, the range of altitude to which the 
airplane is limited, and 360 degrees of heading. Correlation may be 
established on the ground as appropriate.
    (d) Each recorder container must--
    (1) Be either bright orange or bright yellow;
    (2) Have reflective tape affixed to its external surface to 
facilitate its location under water; and
    (3) Have an underwater locating device, when required by the 
operating rules of this chapter, on or adjacent to the container, which 
is secured in such a manner that they are not likely to be separated 
during crash impact.
    (e) Any novel or unique design or operational characteristics of 
the aircraft shall be evaluated to determine if any dedicated 
parameters must be recorded on flight recorders in addition to or in 
place of existing requirements.

Subpart G--Flightcrew Interface and Other Information


Sec.  23.1500  Flightcrew interface.

    (a) The pilot compartment and its equipment must allow each pilot 
to perform his or her duties, including taxi, takeoff, climb, cruise, 
descent, approach, landing, and perform any maneuvers within the 
operating envelope of the airplane, without excessive concentration, 
skill, alertness, or fatigue.
    (b) The applicant must install flight, navigation, surveillance, 
and powerplant controls and displays so qualified flightcrew can 
monitor and perform all tasks associated with the intended functions of 
systems and equipment. The system and equipment design must make the 
possibility that a flightcrew error could result in a catastrophic 
event highly unlikely.


Sec.  23.1505  Instrument markings, control markings, and placards.

    (a) Each airplane must display in a conspicuous manner any placard 
and instrument marking necessary for operation.
    (b) The applicant must clearly mark each cockpit control, other 
than primary flight controls, as to its function and method of 
operation.
    (c) The applicant must include instrument marking and placard 
information in the Airplane Flight Manual.


Sec.  23.1510  Airplane flight manual.

    The applicant must provide an Airplane Flight Manual that must be 
delivered with each airplane that contains the following information--
    (a) Operating limitations and procedures;
    (b) Performance information;
    (c) Loading information; and
    (d) Any other information necessary for the operation of the 
airplane.


Sec.  23.1515  Instructions for continued airworthiness.

    The applicant must prepare Instructions for Continued 
Airworthiness, in accordance with appendix A of this part, that are 
acceptable to the Administrator prior to the delivery of the first 
airplane or issuance of a standard certification of airworthiness, 
whichever occurs later.

Appendix A to Part 23--Instructions for Continued Airworthiness

A23.1 General

    (a) This appendix specifies requirements for the preparation of 
Instructions for Continued Airworthiness as required by this part.
    (b) The Instructions for Continued Airworthiness for each airplane 
must include the Instructions for Continued Airworthiness for each 
engine and propeller (hereinafter designated ``products''), for each 
appliance required by this chapter, and any required information 
relating to the interface of those appliances and products with the 
airplane. If Instructions for Continued Airworthiness are not supplied 
by the manufacturer of an appliance or product installed in the 
airplane, the Instructions for Continued Airworthiness for the airplane 
must include the information essential to the continued airworthiness 
of the airplane.
    (c) The applicant must submit to the FAA a program to show how 
changes to the Instructions for Continued Airworthiness made by the 
applicant or by the manufacturers of products and appliances installed 
in the airplane will be distributed.

A23.2 Format

    (a) The Instructions for Continued Airworthiness must be in the 
form of a manual or manuals as appropriate for the quantity of data to 
be provided.
    (b) The format of the manual or manuals must provide for a 
practical arrangement.

A23.3 Content

    The contents of the manual or manuals must be prepared in the 
English language. The Instructions for Continued Airworthiness must 
contain the following manuals or sections and information:
    (a) Airplane maintenance manual or section.
    (1) Introduction information that includes an explanation of the 
airplane's features and data to the extent necessary for maintenance or 
preventive maintenance.
    (2) A description of the airplane and its systems and installations 
including its engines, propellers, and appliances.
    (3) Basic control and operation information describing how the 
airplane components and systems are controlled and how they operate, 
including any special procedures and limitations that apply.
    (4) Servicing information that covers details regarding servicing 
points, capacities of tanks, reservoirs, types of fluids to be used, 
pressures applicable

[[Page 13527]]

to the various systems, location of access panels for inspection and 
servicing, locations of lubrication points, lubricants to be used, 
equipment required for servicing, tow instructions and limitations, 
mooring, jacking, and leveling information.

(b) Maintenance Instructions

    (1) Scheduling information for each part of the airplane and its 
engines, auxiliary power units, propellers, accessories, instruments, 
and equipment that provides the recommended periods at which they 
should be cleaned, inspected, adjusted, tested, and lubricated, and the 
degree of inspection, the applicable wear tolerances, and work 
recommended at these periods. However, the applicant may refer to an 
accessory, instrument, or equipment manufacturer as the source of this 
information if the applicant shows that the item has an exceptionally 
high degree of complexity requiring specialized maintenance techniques, 
test equipment, or expertise. The recommended overhaul periods and 
necessary cross reference to the Airworthiness Limitations section of 
the manual must also be included. In addition, the applicant must 
include an inspection program that includes the frequency and extent of 
the inspections necessary to provide for the continued airworthiness of 
the airplane.
    (2) Troubleshooting information describing probable malfunctions, 
how to recognize those malfunctions, and the remedial action for those 
malfunctions.
    (3) Information describing the order and method of removing and 
replacing products and parts with any necessary precautions to be 
taken.
    (4) Other general procedural instructions including procedures for 
system testing during ground running, symmetry checks, weighing and 
determining the center of gravity, lifting and shoring, and storage 
limitations.
    (c) Diagrams of structural access plates and information needed to 
gain access for inspections when access plates are not provided.
    (d) Details for the application of special inspection techniques 
including radiographic and ultrasonic testing where such processes are 
specified by the applicant.
    (e) Information needed to apply protective treatments to the 
structure after inspection.
    (f) All data relative to structural fasteners such as 
identification, discard recommendations, and torque values.
    (g) A list of special tools needed.
    (h) In addition, for level 4 airplanes, the following information 
must be furnished--
    (1) Electrical loads applicable to the various systems;
    (2) Methods of balancing control surfaces;
    (3) Identification of primary and secondary structures; and
    (4) Special repair methods applicable to the airplane.

A23.4 Airworthiness limitations section

    The Instructions for Continued Airworthiness must contain a section 
titled Airworthiness Limitations that is segregated and clearly 
distinguishable from the rest of the document. This section must set 
forth each mandatory replacement time, structural inspection interval, 
and related structural inspection procedure required for type 
certification. If the Instructions for Continued Airworthiness consist 
of multiple documents, the section required by this paragraph must be 
included in the principal manual. This section must contain a legible 
statement in a prominent location that reads ``The Airworthiness 
Limitations section is FAA approved and specifies maintenance required 
under Sec. Sec.  43.16 and 91.403 of Title 14 of the Code of Federal 
Regulations unless an alternative program has been FAA approved.''

PART 35--AIRWORTHINESS STANDARDS: PROPELLERS

0
9. The authority citation for part 35 is revised to read as follows:

    Authority: 49 U.S.C. 106(f), 106(g), 40113, 44701-44702, 44704.

0
10. In Sec.  35.1, revise paragraph (c) to read as follows:


Sec.  35.1  Applicability.

* * * * *
    (c) An applicant is eligible for a propeller type certificate and 
changes to those certificates after demonstrating compliance with 
subparts A, B, and C of this part. However, the propeller may not be 
installed on an airplane unless the applicant has shown compliance with 
either Sec.  23.905(c) or Sec.  25.907 of this chapter, as applicable, 
or compliance is not required for installation on that airplane.
* * * * *
0
11. In Sec.  35.37, revise paragraph (c)(1) to read as follows:


Sec.  35.37  Fatigue limits and evaluation.

* * * * *
    (c) * * *
    (1) The intended airplane by complying with Sec.  23.905(c) or 
Sec.  25.907 of this chapter, as applicable; or
* * * * *

PART 43--MAINTENANCE, PREVENTIVE MAINTENANCE, REBUILDING, AND 
ALTERATION

0
12. The authority citation for part 43 is revised to read as follows:

    Authority: 42 U.S.C. 7572; 49 U.S.C. 106(f), 106(g), 40105, 
40113, 44701-44702, 44704, 44707, 44709, 44711, 44713, 44715, 45303.

0
13. In part 43, appendix E, revise the introductory text and paragraph 
(a)(2) to read as follows:

Appendix E to Part 43--Altimeter System Test and Inspection

    Each person performing the altimeter system tests and inspections 
required by Sec.  91.411 must comply with the following:
    (a) * * *
    (2) Perform a proof test to demonstrate the integrity of the static 
pressure system in a manner acceptable to the Administrator. For 
airplanes certificated under part 25 of this chapter, determine that 
leakage is within the tolerances established by Sec.  25.1325.
* * * * *

PART 91--GENERAL OPERATING AND FLIGHT RULES

0
14. The authority citation for part 91 continues to read as follows:

    Authority: 49 U.S.C. 106(f), 106(g), 1155, 40101, 40103, 40105, 
40113, 40120, 44101, 44111, 44701, 44704, 44709, 44711, 44712, 
44715, 44716, 44717, 44722, 46306, 46315, 46316, 46504, 46506-46507, 
47122, 47508, 47528-47531, 47534, articles 12 and 29 of the 
Convention on International Civil Aviation (61 Stat. 1180), (126 
Stat. 11).

0
15. In Sec.  91.205, revise paragraphs (b)(13) and (b)(14), and remove 
paragraph (b)(16) to read as follows:


Sec.  91.205  Powered civil aircraft with standard category U.S. 
airworthiness certificates: Instrument and equipment requirements.

* * * * *
    (b) * * *
    (13) An approved safety belt with an approved metal-to-metal 
latching device, or other approved restraint system for each occupant 2 
years of age or older.
    (14) For small civil airplanes manufactured after July 18, 1978, an 
approved shoulder harness or restraint system for each front seat. For 
small civil airplanes manufactured after December 12, 1986, an approved 
shoulder harness or restraint system for all seats. Shoulder harnesses 
installed at flightcrew stations must permit the flightcrew member, 
when seated and with the safety belt and shoulder harness fastened, to 
perform all

[[Page 13528]]

functions necessary for flight operations. For purposes of this 
paragraph--
    (i) The date of manufacture of an airplane is the date the 
inspection acceptance records reflect that the airplane is complete and 
meets the FAA-approved type design data; and
    (ii) A front seat is a seat located at a flightcrew member station 
or any seat located alongside such a seat.
* * * * *
0
16. In Sec.  91.313, revise paragraph (g) introductory text to read as 
follows:


Sec.  91.313  Restricted category civil aircraft: Operating 
limitations.

* * * * *
    (g) No person may operate a small restricted-category civil 
airplane manufactured after July 18, 1978, unless an approved shoulder 
harness or restraint system is installed for each front seat. The 
shoulder harness or restraint system installation at each flightcrew 
station must permit the flightcrew member, when seated and with the 
safety belt and shoulder harness fastened or the restraint system 
engaged, to perform all functions necessary for flight operation. For 
purposes of this paragraph--
* * * * *
0
17. In Sec.  91.323, revise paragraph (b)(3) to read as follows:


Sec.  91.323  Increased maximum certificated weights for certain 
airplanes operated in Alaska.

* * * * *
    (b) * * *
    (3) The weight at which the airplane meets the positive maneuvering 
load factor n, where n = 2.1 + (24,000/(W + 10,000)) and W = design 
maximum takeoff weight, except that n need not be more than 3.8; or
* * * * *
0
18. In Sec.  91.531, revise paragraphs (a)(1) and (a)(3) to read as 
follows:


Sec.  91.531  Second in command requirements.

    (a) * * *
    (1) A large airplane or normal category level 4 airplane, except 
that a person may operate an airplane certificated under SFAR 41 
without a pilot who is designated as second in command if that airplane 
is certificated for operation with one pilot.
    * * *
    (3) A commuter category airplane or normal category level 3 
airplane, except that a person may operate those airplanes 
notwithstanding paragraph (a)(1) of this section, that have a passenger 
seating configuration, excluding pilot seats, of nine or less without a 
pilot who is designated as second in command if that airplane is type 
certificated for operations with one pilot.
* * * * *

PART 121--OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL 
OPERATIONS

0
19. The authority citation for part 121 continues to read as follows:

    Authority: 49 U.S.C. 106(f), 106(g), 40103, 40113, 40119, 41706, 
42301 preceding note added by Pub. L. 112-95, Sec. 412, 126 Stat. 
89, 44101, 44701-44702, 44705, 44709-44711, 44713, 44716-44717, 
44722, 44729, 44732; 46105; Pub. L. 111-216, 124 Stat. 2348 (49 
U.S.C. 44701 note); Pub. L. 112-95, 126 Stat. 62 (49 U.S.C. 44732 
note).

0
20. In Sec.  121.310, revise paragraph (b)(2)(iii) to read as follows:


Sec.  121.310  Additional emergency equipment.

* * * * *
    (b) * * *
    (2) * * *
    (iii) For a nontransport category turbopropeller powered airplane 
type certificated after December 31, 1964, each passenger emergency 
exit marking and each locating sign must be manufactured to meet the 
requirements of Sec.  23.811(b) of this chapter in effect on June 16, 
1994. On these airplanes, no sign may continue to be used if its 
luminescence (brightness) decreases to below 100 microlamberts.
* * * * *

PART 135--OPERATING REQUIREMENTS: COMMUTER AND ON DEMAND OPERATIONS 
AND RULES GOVERNING PERSONS ON BOARD SUCH AIRCRAFT

0
21. The authority citation for part 135 continues to read as follows:

    Authority: 49 U.S.C. 106(f), 106(g), 41706, 40113, 44701-44702, 
44705, 44709, 44711-44713, 44715-44717, 44722, 44730, 45101-45105; 
Pub. L. 112-95, 126 Stat. 58 (49 U.S.C. 44730).

0
22. In Sec.  135.169, revise paragraphs (b) introductory text, (b)(6), 
and (b)(7), and add paragraph (b)(8) to read as follows:


Sec.  135.169  Additional airworthiness requirements.

* * * * *
    (b) No person may operate a small airplane that has a passenger 
seating configuration, excluding pilot seats, of 10 seats or more 
unless it is type certificated--
* * * * *
    (6) In the normal category and complies with section 1.(b) of 
Special Federal Aviation Regulation No. 41;
    (7) In the commuter category; or
    (8) In the normal category, using a means of compliance accepted by 
the Administrator equivalent to the airworthiness standards applicable 
to the certification of airplanes in the commuter category found in 
part 23 of this chapter through amendment 23-62, effective January 31, 
2012.
* * * * *

    Issued under authority provided by 49 U.S.C. 106(f), 44701(a), 
44703 and Pub. L. 113-53 (127 Stat. 584; 49 U.S.C. 44704 note) in 
Washington, DC, on March 7, 2016.
Dorenda D. Baker,
Director, Aircraft Certification Service.
[FR Doc. 2016-05493 Filed 3-9-16; 11:15 am]
 BILLING CODE 4910-13-P


