
[Federal Register Volume 81, Number 239 (Tuesday, December 13, 2016)]
[Rules and Regulations]
[Pages 89843-89846]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-29769]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 23

[Docket No. FAA-2016-9172; Special Conditions No. 23-276-SC]


Special Conditions: DAHER-SOCATA, Model TBM 700; Inflatable Four-
Point Restraint Safety Belt With an Integrated Airbag Device

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

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SUMMARY: These special conditions are issued for the installation of an 
inflatable four-point restraint safety belt with an integrated airbag 
device at the pilot and copilot seats on the DAHER-SOCATA, Model TBM 
700 airplane. These airplanes, as modified by the installation of these 
inflatable safety belts, will have novel and unusual design features 
associated with the upper-torso restraint portions of the four-point 
safety belts, which contain an integrated airbag device. 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: These special conditions are effective December 13, 2016 and are 
applicable on December 6, 2016.

FOR FURTHER INFORMATION CONTACT: Mr. Bob Stegeman, Federal Aviation 
Administration, Aircraft Certification Service, Small Airplane 
Directorate, ACE-111, 901 Locust, Room 301, Kansas City, MO; telephone 
(816)-329-4140; facsimile (816)-329-4090.

SUPPLEMENTARY INFORMATION: 

Background

    On January 5, 2016, DAHER-SOCATA (SOCATA) applied for FAA 
validation for the optional installation of a four-point safety belt 
restraint system for the pilot and copilot seats and incorporating 
integrated inflatable airbags for both on the Model TBM 700 airplane. 
The Model TBM 700 airplane is a single-engine powering a four bladed 
turbopropellor. It has a maximum takeoff weight of 6578 pounds (2984 
kg). In addition to a pilot and copilot, it can seat up to five 
passengers.
    The inflatable restraint systems are four-point safety belt 
restraint systems consisting of a lap belt and shoulder harness with an 
inflatable airbag attached to the shoulder harness straps. The 
inflatable portion of the restraint system will rely on sensors 
electronically activating the inflator for deployment.
    If an emergency landing occurs, the airbags will inflate and 
provide a protective cushion between the head of the occupant (pilot 
and copilot) and the structure of 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, the airbag is 
integrated into the shoulder harness straps. Airbags and inflatable 
restraints are standard in the automotive industry; the use of an 
inflatable restraint system is novel for general aviation.
    The FAA has determined that this project will be accomplished on 
the basis of providing the same level of safety as the current 
certification requirements of airplane occupant restraint systems. The 
FAA has the following two primary safety concerns with the installation 
of airbags or inflatable restraints that--
    1. They perform properly under foreseeable operating conditions; 
and
    2. They do not perform in a manner or at such times as to impede 
the pilot's 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. Both actions 
may result in a loss of control of the airplane. The consequences are 
magnified due to the low operating altitudes during these phases of 
flight. The FAA has considered this when establishing these special 
conditions.
    The inflatable restraint system relies on sensors to electronically 
activate the inflator 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. SOCATA must show that the effects of an inadvertent deployment 
in flight are not a hazard to the airplane and 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 as a result of this cumulative damage. Therefore, the impact 
of wear and tear resulting with an inadvertent deployment must be 
considered. The effect of this cumulative damage means duration of life 
expectations 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

[[Page 89844]]

testing of the firing hardware and software must consider the 
following--
    1. The airplane vibration levels appropriate for a general aviation 
airplane; and
    2. The 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 
Radiated 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 that 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.
    Where installed, the inflatable restraint system must deploy and 
provide protection for each occupant under an emergency landing 
condition. The Model TBM 700 airplane seats 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. SOCATA 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 pose 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.
    The design must also prevent the inflatable seatbelt from being 
incorrectly buckled or installed to avoid hindering proper deployment 
of the airbag. SOCATA may show that such deployment is not hazardous to 
the occupant and will still provide the required protection.
    The cabins of the SOCATA, Model TBM 700 airplane identified in 
these special conditions are confined areas, 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. The inflatable restraint should be protected from 
the effects of fire to avoid creating an additional hazard such as, a 
rupture of the inflator, for example.
    Finally, the airbag is likely to have a large volume displacement, 
and possibly impede the egress of an occupant. Since the bag 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 offers a level of protection 
throughout an impact event.

Type Certification Basis

    Under the provisions of 14 CFR 21.17, SOCATA must show that the 
Model TBM 700 airplane continues to meet the applicable provisions of 
the applicable regulations in effect on the date of application for the 
type certificate. The regulations incorporated by reference in the type 
certificate are commonly referred to as the original type certification 
basis.
    The certification basis also includes all exemptions, if any; 
equivalent level of safety findings, if any; and special conditions not 
relevant to the special conditions adopted by this rulemaking action.
    If the Administrator determines that the applicable airworthiness 
regulations (i.e., 14 CFR part 23) do not contain adequate or 
appropriate safety standards for the inflatable restraint, as installed 
on the SOCATA, Model TBM 700 airplane 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 Model TBM 700 airplane 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 Sec.  11.19, under 
Sec.  11.38 and they become part of the type certification basis under 
Sec.  21.17(a)(2).
    Special conditions are initially applicable to the models 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 design feature, or should any other model already included on 
the same type certificate be modified to incorporate the same novel or 
unusual design feature, the special conditions would also apply to the 
other model.

Novel or Unusual Design Features

    The SOCATA, Model TBM 700 airplane will incorporate the following 
novel or unusual design feature:
    Installation of inflatable four-point restraint safety belt with an 
integrated airbag device for the pilot and copilot seats.

Discussion

    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 shoulder harness 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 electronically 
activate the inflator for deployment.
    The Code of Federal Regulations states performance criteria for 
seats and restraints in an objective manner. However, none of these 
criteria are adequate to address the specific issues raised concerning 
inflatable restraints. Therefore, the FAA has determined that in 
addition to the requirements of part 21 and part 23, special conditions 
are needed to address the installation of this inflatable restraint.
    Accordingly, these special conditions are adopted for the SOCATA, 
Model

[[Page 89845]]

TBM 700 airplanes equipped with four-point inflatable restraints. Other 
conditions may be developed, as needed, based on further FAA review and 
discussions with the manufacturer and civil aviation authorities.

Discussion of Comments

    Final special conditions number 23-276-SC \1\ for the DAHER-SOCATA, 
Model TBM 700 airplanes and requesting comments was published in the 
Federal Register on September 30, 2016 (81 FR 67093). One comment was 
received that compared restraint safety to that of an automobile and 
stressed the importance considering airbag safety, the possibility of 
injuring or killing occupants during deployment and considerations for 
occupant safety for a range of occupants.
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    \1\ https://www.regulations.gov/document?D=FAA-2016-9172-0001.
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    Aircraft accidents differ from car accidents in that they typically 
involve much higher speeds and also introduce a vertical impact 
component. The aviation regulations require an assessment of occupant 
safety in the horizontal and vertical planes. An airbag is normally 
triggered, deployed, and effective only in the horizontal plane. The 
special condition requires assessment for 5th percentile females to 
95th percentile males. As such, very large and very small occupants are 
not considered in this special condition, but this is consistent with 
other FAA occupant safety rules.
    Aircraft airbags, or inflatable restraints, (including the airbags 
subject to this special condition) are fundamentally different in their 
operation in comparison to automotive airbags. Automotive airbags 
normally deploy from the dashboard or steering wheel and push against 
the rigid structure as they powerfully deploy and engage the occupant. 
Inflatable restraints have the airbag deploy from the restraint and 
push away from the occupant and do not press on the occupant until the 
occupant, with significant inertia, is moving forward and impacting the 
interior. Smaller occupants, normally those killed by automotive 
airbags, are not as likely to engage the aircraft inflatable restraints 
against the interior.
    There are no known fatalities or significant injuries from aircraft 
inflatable restraints that are attributable only to the airbag 
deployment itself. By nature, the inflatable restraints move away from 
the occupant, so injury to the occupant from deployment is very 
unlikely. Smaller occupants and children are still recommended to ride 
in aft seating, like in an automobile. These special conditions do 
consider and peripherally address a range of occupant sizes consistent 
with part 23 occupant safety rules.
    This special condition does address the potential hazards commented 
upon, and the safety and effectiveness of the airbag system with 
consideration to a range of occupant sizes. No changes were made as a 
result of this comment, and the special conditions are adopted as 
proposed.

Applicability

    As discussed above, these special conditions are applicable to the 
SOCATA, Model TBM 700 airplane. Should SOCATA 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.
    Under standard practice, the effective date of final special 
conditions would be 30 days after the date of publication in the 
Federal Register; however, as the certification date for the SOCATA, 
Model TBM 700 airplane is imminent, the FAA finds that good cause 
exists to make these special conditions effective upon issuance.

Conclusion

    This action affects only certain novel or unusual design features 
on one model of airplanes. It is not a rule of general applicability 
and affects only the applicant who applied to the FAA for approval of 
these features on the airplane.

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 11.38 and 11.19.

The Special Conditions

    The FAA has determined that this project will be accomplished on 
the basis of not lowering the current level of safety of the SOCATA, 
Model TBM 700 airplane occupant restraint systems. 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 SOCATA, Model TBM 700 airplane.

1. Installation of Inflatable Four-Point Restraint Safety Belt With an 
Integrated Airbag Device

    a. It must be shown that the inflatable restraint will deploy and 
provide protection under emergency landing 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 
the 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 incorrectly installed, such that the airbag 
would not properly deploy. 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 
the 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, TSO-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 will not 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 also 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

[[Page 89846]]

the occupants 10 seconds after its deployment.
    i. To comply 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 before 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 vibration levels appropriate for a general aviation 
airplane.

    Issued in Kansas City, Missouri, on December 6, 2016.
Kelly Broadway,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2016-29769 Filed 12-12-16; 8:45 am]
 BILLING CODE 4910-13-P


