
[Federal Register Volume 78, Number 176 (Wednesday, September 11, 2013)]
[Rules and Regulations]
[Pages 55629-55632]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2013-22101]



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  Federal Register / Vol. 78, No. 176 / Wednesday, September 11, 2013 / 
Rules and Regulations  

[[Page 55629]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 23

[Docket No. FAA-2013-0781; Special Conditions No. 23-261-SC]


Special Conditions: Cirrus Design Corporation, Model SF50; 
Inflatable Three-Point Restraint Safety Belt With an Integrated Airbag 
Device

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions; request for comments.

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SUMMARY: These special conditions are issued for the Cirrus Design 
Corporation (Cirrus), model SF50. This airplane will have novel and 
unusual design features associated with installation of an inflatable 
three-point restraint safety belt with an integrated airbag device at 
the pilot and co-pilot seats to include optional installations at other 
passenger seat locations. The applicable airworthiness regulations do 
not contain adequate or appropriate safety standards for this design 
feature. These 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: The effective date of these special conditions is September 11, 
2013. We must receive comments by October 11, 2013.

ADDRESSES: Send comments identified by docket number [FAA-2013-0781] 
using any of the following methods:
    [square] Federal eRegulations Portal: Go to http://www.regulations.gov and follow the online instructions for sending your 
comments electronically.
    [square] 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.
    [square] Hand Delivery of 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.
    [square] Fax: Fax comments to Docket Operations at 202-493-2251.
    Privacy: The FAA will post all comments it receives, without 
change, to http://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: Mr. Bob Stegeman, Federal Aviation 
Administration, Aircraft Certification Service, Small Airplane 
Directorate, ACE-111, 901 Locust, Kansas City, Missouri, 816-329-4140, 
fax 816-329-4090.

SUPPLEMENTARY INFORMATION: The FAA has determined that notice and 
opportunity for prior public comment is impractical because these 
procedures would significantly delay issuance of approval and thus 
delivery of the affected aircraft. In addition, the substance of these 
special conditions has been subject to the public comment process in 
several prior instances with no substantive comments received. The FAA, 
therefore, finds that good cause exists for making these special 
conditions effective upon issuance.

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 ask 
that you send us two copies of written comments.
    We will consider all comments we receive on or before the closing 
date for comments. We will consider comments filed late if it is 
possible to do so without incurring expense or delay. We may change 
these special conditions based on the comments we receive.

Background

    On September 9, 2008, Cirrus applied for a Type Certificate for 
their new Model SF50. The SF50 is a single-engine turbofan powered jet 
that can carry up to seven occupants.
    This aircraft will include a three-point safety belt restraint 
system with integrated airbags for the pilot and co-pilot seats. The 
aircraft will have airbags as a standard feature on all of the pilot 
and copilot seat locations with optional airbags offered at other 
passenger locations. Optional locations must meet all applicable 
special conditions.
    The inflatable restraint systems are a three-point safety belt 
restraint system consisting of a lap belt and shoulder harness with an 
inflatable airbag attached to the lap belt. The inflatable portion of 
the restraint system will rely on sensors to activate the inflator 
electronically for deployment.
    When activated, the airbags will inflate and provide a protective 
cushion between the occupant's head and the structure within the 
airplane. This will reduce the potential for head and torso injury. The 
inflatable restraint behaves in a manner similar to an automotive 
airbag; however, in this case, the airbag is integrated into the lap 
belt. While airbags and inflatable restraints are standard in the 
automotive industry, the use of an inflatable restraint system is novel 
for general aviation operations.
    The FAA has determined that this project will be accomplished based 
on providing the same current level of safety as the conventional 
certification basis airplane occupant restraint systems. The FAA has 
two primary safety concerns with the installation of airbags or 
inflatable restraints:
     They perform properly under foreseeable operating 
conditions; and
     They do not perform in a manner or at such times as to 
impede the pilot's

[[Page 55630]]

ability to maintain control of the airplane or constitute a hazard to 
the airplane or occupants.
    The latter point has the potential to be the more rigorous of the 
requirements. An unexpected deployment while conducting the takeoff or 
landing phases of flight may result in an unsafe condition. The 
unexpected deployment may either startle the pilot or generate a force 
sufficient to cause a sudden movement of the control yoke. Either 
action could result in a loss of control of the airplane, the 
consequences of which are magnified due to the low operating altitudes 
and speeds during these phases of flight. The FAA has considered this 
when establishing these special conditions.
    The inflatable restraint system relies on sensors to activate the 
inflator electronically for deployment. These sensors could be 
susceptible to inadvertent activation, causing deployment in a 
potentially unsafe manner. The consequences of an inadvertent 
deployment must be considered in establishing the reliability of the 
system. The applicant must show that the effects of an inadvertent 
deployment in flight are not a hazard to the airplane or that an 
inadvertent deployment is extremely improbable. In addition, general 
aviation aircraft are susceptible to a large amount of cumulative wear 
and tear on a restraint system. The potential for inadvertent 
deployment may increase because of this cumulative damage. Therefore, 
the impact of wear and tear on inadvertent deployment must be 
considered. The effect of this cumulative damage means a life limit 
must be established for the appropriate system components in the 
restraint system design.
    There are additional factors to be considered to minimize the 
chances of inadvertent deployment. General aviation airplanes are 
exposed to a unique operating environment, since the same airplane may 
be used by both experienced and student pilots. The effect of this 
environment on inadvertent deployment must be understood. Therefore, 
qualification testing of the firing hardware/software must consider the 
following:
     The airplane vibration levels appropriate for a general 
aviation airplane; and
     The airplane inertial loads that result from typical 
flight or ground maneuvers, including gusts and hard landings.

Any tendency for the firing mechanism to activate as a result of these 
loads or acceleration levels is unacceptable.
    Other influences on inadvertent deployment include High Intensity 
Electromagnetic Fields (HIRF) and lightning. Since the sensors that 
trigger deployment are electronic, they must be protected from the 
effects of these threats. To comply with HIRF and lightning 
requirements, the inflatable restraint system is considered a critical 
system, since its inadvertent deployment could have a hazardous effect 
on the airplane.
    Given the level of safety of the occupant restraints currently 
installed, the inflatable restraint system must show it will offer an 
equivalent level of protection for an emergency landing. If an 
inadvertent deployment occurs, the restraint must still be at least as 
strong as a Technical Standard Order approved belt and shoulder 
harnesses. There is no requirement for the inflatable portion of the 
restraint to offer protection during multiple impacts, where more than 
one impact would require protection.
    The inflatable restraint system must deploy and provide protection 
for each occupant under an emergency landing condition. The seats of 
the model SF50 airplanes are certificated to the structural 
requirements of Sec.  23.562; therefore, the test emergency landing 
pulses identified in Sec.  23.562 must be used to satisfy this 
requirement.
    A wide range of occupants may use the inflatable restraint; 
therefore, the protection offered by this restraint should be effective 
for occupants that range from the fifth percentile female to the 
ninety-fifth percentile male. Energy absorption must be performed in a 
consistent manner for this occupant range.
    In support of this operational capability, there must be a means to 
verify the integrity of this system before each flight. Cirrus may 
establish inspection intervals where they have demonstrated the system 
to be reliable between these intervals.
    An inflatable restraint may be ``armed'' even though no occupant is 
using the seat. While there will be means to verify the integrity of 
the system before flight, it is also prudent to require unoccupied 
seats with active restraints not constitute a hazard to any occupant. 
This will protect any individual performing maintenance inside the 
cockpit while the aircraft is on the ground. The restraint must also 
provide suitable visual warnings that would alert rescue personnel to 
the presence of an inflatable restraint system.
    In addition, the design must prevent the inflatable seatbelt from 
being incorrectly buckled and/or installed such that the airbag would 
not properly deploy. Cirrus may show that such deployment is not 
hazardous to the occupant and will still provide the required 
protection.
    The cabin of the Cirrus model SF50 airplane is a confined area and 
the FAA is concerned that noxious gasses may accumulate if the airbag 
deploys. When deployment occurs, either by design or inadvertently, 
there must not be a release of hazardous quantities of gas or 
particulate matter into the cockpit.
    An inflatable restraint should not increase the risk already 
associated with fire. Therefore, the inflatable restraint should be 
protected from the effects of fire to avoid creating an additional 
hazard by, for example, a rupture of the inflator.
    Finally, the airbag is likely to have a large volume displacement, 
and possibly impede the egress of an occupant. Since the airbag 
deflates to absorb energy, it is likely that the inflatable restraint 
would be deflated at the time an occupant would attempt egress. 
However, it is appropriate to specify a time interval after which the 
inflatable restraint may not impede rapid egress. Ten seconds has been 
chosen as reasonable time. This time limit will offer a level of 
protection throughout the impact event.

Type Certification Basis

    Under the provisions of 14 CFR 21.17, Cirrus must show that the 
model SF50 meets the applicable provisions of part 23, as amended by 
amendment 23-62 thereto.
    If the Administrator finds that the applicable airworthiness 
regulations (i.e., 14 CFR part 23, Amendment 23-62) do not contain 
adequate or appropriate safety standards for the SF50 because of a 
novel or unusual design feature, special conditions are prescribed 
under the provisions of Sec.  21.16.
    In addition to the applicable airworthiness regulations and special 
conditions, the SF50 must comply with the fuel vent and exhaust 
emission requirements of 14 CFR part 34, amendment 34-4, and the noise 
certification requirements of 14 CFR part 36, amendment 36-28; 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 in accordance with Sec. Sec.  
11.19 and 11.38 and they become part of the type certification basis 
under Sec.  21.17(a)(2).
    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 novel or 
unusual

[[Page 55631]]

design feature, the special conditions would also apply to the other 
model.

Novel or Unusual Design Features

    The SF50 will incorporate the following novel or unusual design 
feature:
    A three-point safety belt restraint system incorporating an 
inflatable airbag.

Discussion

    The SF50 will have novel and unusual design features associated 
with installation of an inflatable three-point restraint safety belt 
with an integrated airbag device at the pilot and co-pilot seats. The 
manufacturer will also offer optional airbags at other passenger 
locations. Optional locations must meet all applicable special 
conditions. The purpose of the airbag is to reduce the potential for 
injury in the event of an accident. In a severe impact, an airbag will 
deploy from the lap belt in a manner similar to an automotive airbag. 
The airbag will deploy between the head of the occupant and airplane 
interior structure, which will provide some protection to the head of 
the occupant. The restraint will rely on sensors to activate the 
inflator electronically for deployment.
    Section 23.562 states performance criteria for seats and restraints 
in an objective manner. However, none of these criteria is adequate to 
address the specific issues raised concerning inflatable restraints. 
Therefore, the FAA has determined that, in addition to the requirements 
of parts 21 and 23, special conditions are needed to address the 
installation of this inflatable restraint.
    Accordingly, these special conditions are adopted for the Cirrus 
Design Corporation Model SF50 airplane equipped with three-point 
inflatable restraints. Other conditions may be developed, as needed, 
based on further FAA review and discussions with the manufacturer and 
civil aviation authorities.

Applicability

    As discussed above, these special conditions are applicable to the 
model SF50 equipped with the three-point inflatable restraint systems. 
Should Cirrus Design Corporation 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 model SF50 airplanes. It is not a rule of general applicability and 
it affects only the applicant who applied to the FAA for approval of 
these features on the airplane.
    The substance of these special conditions has been subjected to the 
notice and comment period in several prior instances and has been 
derived without substantive change from those previously issued. It is 
unlikely that prior public comment would result in a significant change 
from the substance contained herein. Therefore, because a delay would 
significantly affect the certification of the airplane, which is 
imminent, the FAA has determined that prior public notice and comment 
are unnecessary and impracticable, and good cause exists for adopting 
these special conditions upon issuance. The FAA is requesting comments 
to allow interested persons to submit views that may not have been 
submitted in response to the prior opportunities for comment described 
above.

List of Subjects in 14 CFR Part 23

    Aircraft, Aviation safety, Signs and symbols.

Citation

    The authority citation for these special conditions is as follows:

    Authority:  49 U.S.C. 106(g), 40113 and 44701; 14 CFR 21.16 and 
21.17; and 14 CFR 11.19 and 11.38.

The Special Conditions

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the following special conditions are issued as part of 
the type certification basis for the Cirrus Design Corporation Model SF 
50 airplane.

1. Inflatable Three-Point Restraint Safety Belt with an Integrated 
Airbag Device

    a. It must be shown that the inflatable restraint will deploy and 
provide protection under crash conditions. Compliance will be 
demonstrated using the dynamic test condition specified in Sec.  
23.562(b)(2). It is not necessary to account for floor warpage, as 
required by Sec.  23.562(b)(3), or vertical dynamic loads, as required 
by Sec.  23.562(b)(1). The means of protection must take into 
consideration a range of stature from a 5th percentile female to a 95th 
percentile male. The inflatable restraint must provide a consistent 
approach to energy absorption throughout that range.
    b. The inflatable restraint must provide adequate protection for 
each occupant. In addition, unoccupied seats that have an active 
restraint must not constitute a hazard to any occupant.
    c. The design must prevent the inflatable restraint from being 
incorrectly buckled and/or incorrectly installed such that the airbag 
would not properly deploy. Alternatively, it must be shown that such 
deployment is not hazardous to the occupant and will provide the 
required protection.
    d. It must be shown that the inflatable restraint system is not 
susceptible to inadvertent deployment as a result of wear and tear or 
inertial loads resulting from in-flight or ground maneuvers (including 
gusts and hard landings) that are likely to be experienced in service.
    e. It must be extremely improbable for an inadvertent deployment of 
the restraint system to occur, or an inadvertent deployment must not 
impede the pilot's ability to maintain control of the airplane or cause 
an unsafe condition (or hazard to the airplane). In addition, a 
deployed inflatable restraint must be at least as strong as a Technical 
Standard Order (C114) certificated belt and shoulder harness.
    f. It must be shown that deployment of the inflatable restraint 
system is not hazardous to the occupant or result in injuries that 
could impede rapid egress. This assessment should include occupants 
whose restraint is loosely fastened.
    g. It must be shown that an inadvertent deployment that could cause 
injury to a standing or sitting person is improbable. In addition, the 
restraint must provide suitable visual warnings that would alert rescue 
personnel to the presence of an inflatable restraint system.
    h. It must be shown that the inflatable restraint will not impede 
rapid egress of the occupants 10 seconds or later after its deployment.
    i. For the purposes of complying with HIRF and lightning 
requirements, the inflatable restraint system is considered a critical 
system since its deployment could have a hazardous effect on the 
airplane.
    j. It must be shown that the inflatable restraints will not release 
hazardous quantities of gas or particulate matter into the cabin.
    k. The inflatable restraint system installation must be protected 
from the effects of fire such that no hazard to occupants will result.
    l. There must be a means to verify the integrity of the inflatable 
restraint activation system prior to each flight or it must be 
demonstrated to reliably operate between inspection intervals.
    m. A life limit must be established for appropriate system 
components.
    n. Qualification testing of the internal firing mechanism must be 
performed at

[[Page 55632]]

vibration levels appropriate for a general aviation airplane.

    Issued in Kansas City, Missouri on September 4, 2013.
Earl Lawrence,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 2013-22101 Filed 9-10-13; 8:45 am]
BILLING CODE 4910-13-P


