
[Federal Register Volume 78, Number 238 (Wednesday, December 11, 2013)]
[Proposed Rules]
[Pages 75287-75289]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2013-29487]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2013-1040; Notice No. 25-13-39-SC]


Special Conditions: Bombardier Inc., Models BD-500-1A10 and BD-
500-1A11 Series Airplanes; Flight Envelope Protection: General Limiting 
Requirements

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed special conditions.

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SUMMARY: This action proposes special conditions for the Bombardier 
Inc. Models BD-500-1A10 and BD-500-1A11 series airplanes. These 
airplanes will have a novel or unusual design feature associated with a 
new control architecture and a full digital flight control system that 
provides flight envelope protections. The applicable airworthiness 
regulations do not contain adequate or appropriate safety standards for 
this design feature. The applicable airworthiness regulations do not 
contain adequate or appropriate safety standards for this design 
feature. These proposed special conditions contain the additional 
safety standards that the Administrator considers necessary to 
establish a level of safety equivalent to that established by the 
existing airworthiness standards.

DATES: Send your comments on or before January 27, 2014.

ADDRESSES: Send comments identified by docket number FAA-2013-1040 
using any of the following methods:
     Federal eRegulations 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: The FAA will post all comments it receives, without 
change, to http://www.regulations.gov/, including any personal 
information the commenter provides. Using the search function of the 
docket Web site, anyone can find and read the electronic form of all 
comments received into any FAA docket, including the name of the 
individual sending the comment (or signing the comment for an 
association, business, labor union, etc.). DOT's complete Privacy Act 
Statement can be found in the Federal Register published on April 11, 
2000 (65 FR 19477-19478), as well as at http://DocketsInfo.dot.gov/.
    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: Joe Jacobsen, FAA, Airplane and Flight 
Crew Interface Branch, ANM-111, Transport Airplane Directorate, 
Aircraft Certification Service, 1601 Lind Avenue SW., Renton, 
Washington, 98057-3356; telephone 425-227-2011; facsimile 425-227-1149.

SUPPLEMENTARY INFORMATION:

[[Page 75288]]

Comments Invited

    We invite interested people to take part in this rulemaking by 
sending written comments, data, or views. The most helpful comments 
reference a specific portion of the special conditions, explain the 
reason for any recommended change, and include supporting data.
    We will consider all comments we receive on or before the closing 
date for comments. We may change these special conditions based on the 
comments we receive.

Background

    On December 10, 2009, Bombardier Inc. applied for a type 
certificate for their new Models BD-500-1A10 and BD-500-1A11 series 
airplanes (hereafter collectively referred to as ``C-series''). The C-
series airplanes are swept-wing monoplanes with a pressurized cabin. 
They share an identical supplier base and significant common design 
elements. The fuselage is aluminum alloy material, blended double-
bubble fuselage, sized for nominal 5-abreast seating. Each airplane's 
powerplant consists of two under wing Pratt and Whitney PW1524G ultra-
high bypass, geared turbofan engines. Flight controls are fly-by-wire 
flight with two passive/uncoupled side sticks. Avionics includes five 
landscape primary cockpit displays. The dimension of the airplanes 
encompass a wingspan of 115 feet; a height of 37.75 feet; and a length 
of 114.75 feet for the Model BD-500-1A10 and a length of 127 feet for 
the Model BD-500-1A11. Passenger capacity is designated as 110 for the 
Model BD-500-1A10 and 125 for the Model BD-500-1A11. Maximum takeoff 
weight is 131,000 pounds for the Model BD-500-1A10 and 144,000 pounds 
for the Model BD-500-1A11. Maximum takeoff thrust is 21,000 pounds for 
the Model BD-500-1A10 and 23,300 pounds for the Model BD-500-1A11. 
Range is 3,394 miles (5,463 kilometers) for both models of airplanes. 
Maximum operating altitude is 41,000 feet for both model airplanes.
    Bombardier has developed comprehensive flight envelope protection 
features integral to the C-series electronic flight control system 
(EFCS) design. These flight envelope protection features include 
limitations on angle-of-attack, normal load factor, bank angle, pitch 
angle, and speed. To accomplish this flight envelope limiting, a 
significant change (or multiple changes) occurs in the EFCS control 
laws as the limit is approached or exceeded. When EFCS failure states 
occur, flight envelope protection features can likewise either be 
modified, or in some cases, eliminated. The current regulations were 
not written with these comprehensive flight envelope limiting systems 
in mind.

Type Certification Basis

    Under the provisions of Title 14, Code of Federal Regulations (14 
CFR) 21.17, Bombardier Inc. must show that the C-series airplanes meet 
the applicable provisions of part 25 as amended by Amendments 25-1 
through 25-129 thereto.
    If the Administrator finds that the applicable airworthiness 
regulations (i.e., 14 CFR part 25) do not contain adequate or 
appropriate safety standards for the C-series airplanes because of a 
novel or unusual design feature, special conditions are prescribed 
under the provisions of Sec.  21.16.
    Special conditions are initially applicable to the model for which 
they are issued. Should the type certificate for that model be amended 
later to include any other model that incorporates the same or similar 
novel or unusual design feature, the special conditions would also 
apply to the other model under Sec.  21.101.
    In addition to the applicable airworthiness regulations and special 
conditions, the C-series airplanes must comply with the fuel vent and 
exhaust emission requirements of 14 CFR part 34 and the noise 
certification requirements of 14 CFR part 36, and the FAA must issue a 
finding of regulatory adequacy under Sec.  611 of Public Law 92-574, 
the ``Noise Control Act of 1972.''
    The FAA issues special conditions, as defined in 14 CFR 11.19, in 
accordance with Sec.  11.38, and they become part of the type-
certification basis under Sec.  21.17(a)(2).

Novel or Unusual Design Features

    The C-series airplanes will incorporate the following novel or 
unusual design features: new control architecture and a full digital 
flight control system that provides comprehensive flight envelope 
protections.

Discussion

    The applicable airworthiness regulation in this instance is 14 CFR 
25.143. The purpose of Sec.  25.143 is to verify that any operational 
maneuvers conducted within the operational envelope can be accomplished 
smoothly with average piloting skill and without exceeding any 
structural limits. The pilot should be able to predict the airplane 
response to any control input. During the course of the flight test 
program, the pilot determines compliance with Sec.  25.143 through 
primarily qualitative methods. During flight test, the pilot should 
evaluate all of the following:
     The interface between each protection function;
     Transitions from one mode to another;
     The aircraft response to intentional dynamic maneuvering, 
whenever applicable, through dedicated maneuvers;
     General controllability assessment;
     High speed characteristics; and
     High angle-of-attack.
    Section 25.143, however, does not adequately ensure that the novel 
or unusual features of the C-series airplanes will have a level of 
safety equivalent to that of existing standards. These special 
conditions are therefore required to accommodate the flight envelope 
limiting systems in the C-series airplanes. The additional safety 
standards in these special conditions will ensure a level of safety 
equivalent to that of existing standards.

Applicability

    As discussed above, these special conditions are applicable to the 
Models BD-500-1A10 and BD-500-1A11 series airplanes. Should Bombardier 
Inc. apply at a later date for a change to the type certificate to 
include another model incorporating the same novel or unusual design 
feature, the special conditions would apply to that model as well.

Conclusion

    This action affects only certain novel or unusual design features 
on two model series of airplanes. It is not a rule of general 
applicability.

List of Subjects in 14 CFR Part 25

    Aircraft, Aviation safety, Reporting and recordkeeping 
requirements.

    The authority citation for these special conditions is as follows:

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

The Proposed Special Conditions

    Accordingly, the Federal Aviation Administration (FAA) proposes the 
following special conditions as part of the type certification basis 
for the Bombardier Inc. Models BD-500-1A10 and BD-500-1A11 series 
airplanes.
    1. General Limiting Requirements:
    a. Onset characteristics of each envelope protection feature must 
be smooth, appropriate to the phase of flight and type of maneuver, and 
not in conflict with the ability of the pilot to satisfactorily change 
airplane flight path, speed, or attitude as needed.

[[Page 75289]]

    b. Limit values of protected flight parameters (and if applicable, 
associated warning thresholds) must be compatible with the following:
    i. Airplane structural limits,
    ii. Required safe and controllable maneuvering of the airplane, and
    iii. Margins to critical conditions. Unsafe flight characteristics/
conditions must not result if dynamic maneuvering, airframe and system 
tolerances (both manufacturing and in-service), and non-steady 
atmospheric conditions, in any appropriate combination and phase of 
flight, can produce a limited flight parameter beyond the nominal 
design limit value.
    c. The airplane must be responsive to intentional dynamic 
maneuvering to within a suitable range of the parameter limit. Dynamic 
characteristics such as damping and overshoot must also be appropriate 
for the flight maneuver and limit parameter in question.
    d. When simultaneous envelope limiting is engaged, adverse coupling 
or adverse priority must not result.
    2. Failure States: Electronic flight control system failures 
(including sensor) must not result in a condition where a parameter is 
limited to such a reduced value that safe and controllable maneuvering 
is no longer available. The crew must be alerted by suitable means if 
any change in envelope limiting or maneuverability is produced by 
single or multiple failures of the electronic flight control system not 
shown to be extremely improbable.

    Issued in Renton, Washington, on November 29, 2013.
Jeffrey E. Duven,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2013-29487 Filed 12-10-13; 8:45 am]
BILLING CODE 4910-13-P


