Document ID: FAA-2019-1055-0002
Agency: faa
Document Type: Rule
Title: Special Conditions: Boeing Commercial Airplanes Model 777-9 Airplanes; Structure-Mounted Airbags
Posted Date: 2021-03-15T04:00Z

[Federal Register Volume 86, Number 48 (Monday, March 15, 2021)]
[Rules and Regulations]
[Pages 14229-14231]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-05308]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2019-1055; Special Conditions No. 25-778-SC]

Special Conditions: Boeing Commercial Airplanes Model 777-9 
Airplanes; Structure-Mounted Airbags

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

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SUMMARY: These special conditions are issued for the Boeing Commercial 
Airplanes (Boeing) Model 777-9 airplane. This airplane will have a 
novel or unusual design feature when compared to the state of 
technology envisioned in the airworthiness standards for transport-
category airplanes. This design feature is structure-mounted airbags 
designed to limit occupant forward excursion in the event of an 
emergency landing. 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: Effective April 14, 2021.

FOR FURTHER INFORMATION CONTACT: Shannon Lennon, Airframe and Cabin 
Safety Section, AIR-675, Transport Standards Branch, Policy and 
Innovation Division, Aircraft Certification Service, Federal Aviation 
Administration, 2200 South 216th Street, Des Moines, Washington 98198; 
telephone and fax 206-231-3209; email shannon.lennon@faa.gov.

SUPPLEMENTARY INFORMATION:

Background

    On December 6, 2013, Boeing applied for a change to Type 
Certificate No. T00001SE for structure-mounted airbags installed in the 
Boeing Model 777-9 airplane. The application date was extended to March 
30, 2016, based on Boeing's request. The Boeing Model 777-9 airplane, 
which is a derivative of the Boeing Model 777 airplane currently 
approved under Type Certificate No. T00001SE, is a twin-engine, 
transport-category airplane with seating for 495 passengers and a 
maximum takeoff weight of 775,000 pounds.

Type Certification Basis

    Under the provisions of title 14, Code of Federal Regulations (14 
CFR) 21.101, Boeing must show that the Model 777-9 airplane, as 
changed, continues to meet the applicable provisions of the regulations 
listed in Type Certificate No. T00001SE, or the applicable regulations 
in effect on the date of application for the change, except for earlier 
amendments as agreed upon by the FAA.
    If the Administrator finds that the applicable airworthiness 
regulations (e.g., 14 CFR part 25) do not contain adequate or 
appropriate safety standards for the Boeing Model 777-9 airplane 
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 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, these special conditions would also apply to 
the other model under Sec.  21.101.
    In addition to the applicable airworthiness regulations and special 
conditions, the Boeing Model 777-9 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.
    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.  21.101.

Novel or Unusual Design Features

    The Boeing Model 777-9 airplane will incorporate the following 
novel or unusual design features:
    Airbags mounted to structure to prevent head injury.

Discussion

    Boeing will install structure-mounted airbags instead of inflatable 
lap belts as a means to protect each occupant from serious injury in 
the event of an emergency landing, as required by Sec.  25.562(c)(5), 
on 777-9 airplanes.
    Such use of airbags to provide injury protection for the occupant 
is a novel or unusual feature for this airplane model, and the 
applicable airworthiness regulations do not contain adequate or 
appropriate airworthiness standards for these design features. 
Therefore, special conditions are needed to address requirements 
particular to installation of airbags in this manner.
    Special conditions exist for airbags installed on seat belts, known 
as inflatable lap belts, which have been installed on Boeing airplane 
passenger seats. Structure-mounted airbags, although a novel design, 
were first introduced on Jetstream Aircraft Limited Model 4100 series 
airplanes, which resulted in issuance of Special Conditions 25-ANM-127 
on May 14, 1997. These special conditions supplemented 14 CFR part 25 
and, more specifically, Sec. Sec.  25.562 and 25.785.
    The structure-mounted airbag, similar to the inflatable lap belt, 
is designed to limit occupant forward excursion in the event of an 
emergency landing. These airbags will reduce the potential for serious 
injury, including reducing the head-injury criterion measurement 
defined in part 25. However, structure-mounted airbags function 
similarly as automotive airbags, where the airbag deploys from 
furniture located in front of the passenger, relative to the airplane's 
direction of flight, forming a barrier between the structure and

[[Page 14230]]

occupant. Also, unlike the inflatable lap belt, the structure-mounted 
airbag does not move with the occupant. To account for out-of-position 
and brace-position occupants, the airbag is designed to conform to the 
curvature of the exposed structure in the head-strike zone.
    Because the airbag system is essentially a single-use device, it 
could deploy under crash conditions that are not sufficiently so severe 
as to require the injury protection the airbag system provides. Because 
an actual crash is frequently composed of a series of impacts before 
the airplane comes to rest, a larger impact following the initial 
impact could render the airbag system unavailable. This potential 
situation does not exist with standard upper-torso restraints, which 
tend to provide continuous protection regardless of impact severity, or 
number of impacts, in a crash event. Therefore, the airbag-system 
installation should be such that it provides protection, when it is 
required, by not expending its protection when it is not required. If 
the airbag deployment threshold is unnecessarily low, the airbag would 
need to continue to provide protection when an impact requiring 
protection occurs.
    These special conditions are based upon special conditions 25-605-
SC for the Boeing Model 787-9 airplanes equipped with B/E Aerospace 
Super-Diamond model business-class passenger seats and associated 
furniture.
    The 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.

Discussion of Comments

    The FAA issued Notice of Proposed Special Conditions No. 25-20-05-
SC for the Boeing) Model 777-9 airplane, which was published in the 
Federal Register on July 22, 2020 (85 FR 44244). No comments were 
received, and the special conditions are adopted as proposed.

Applicability

    As discussed above, these special conditions are applicable to the 
Boeing Model 777-9 airplane. Should Boeing apply at a later date for a 
change to the type certificate to include another model incorporating 
the same novel or unusual design feature, these special conditions 
would apply to that model as well.

Conclusion

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

List of Subjects in 14 CFR Part 25

    Aircraft, Aviation safety, Reporting and recordkeeping 
requirements.

Authority Citation

    The authority citation for these special conditions is as follows:

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

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 Boeing Model 777-9 airplanes.
    1. The applicant must demonstrate by test that the structure-
mounted airbag will deploy and provide protection under crash 
conditions where it is necessary to prevent serious injury to a 50th 
percentile occupant, as specified in Sec.  25.562. The means of 
protection must provide a consistent approach to energy absorption for 
a range of occupants, from a two-year-old child to a 95th percentile 
male.
    2. The structure-mounted airbag must provide adequate protection 
for each occupant regardless of the number of occupants of the seat 
assembly.
    3. The structure-mounted airbag system must not be 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) likely to be experienced in service.
    4. Deployment of the structure-mounted airbag must not introduce 
hazards or injury mechanisms to the seated occupant, including 
occupants in the brace position. Deployment of the structure-mounted 
airbag must also not result in injuries that could impede rapid exit 
from the airplane.
    5. The applicant must demonstrate that an inadvertent deployment 
that could cause injury to a standing or sitting person is improbable. 
Inadvertent deployment must not cause injury to anyone who may be 
positioned close to the structure-mounted airbag (e.g., seated in an 
adjacent seat, or standing adjacent to the airbag installation or the 
subject seat). Cases where a structure-mounted airbag is inadvertently 
deployed near a seated occupant or an empty seat must be considered.
    6. Effects of the deflection and deformation of the structure to 
which the airbag is attached must be taken into account when evaluating 
deployment and location of the inflated airbag. The effect of loads 
imposed by airbag deployment, or stowed components where applicable, 
must also be taken into account.
    7. Inadvertent deployment of the structure-mounted airbag during 
the most critical part of flight will either not cause a hazard to the 
airplane or is extremely improbable.
    8. The applicant must demonstrate that the structure-mounted 
airbag, when deployed, does not impair access to the seatbelt- or 
harness-release means, and must not hinder evacuation. This will 
include consideration of adjacent seat places and the aisle.
    9. The airbag, once deployed, must not adversely affect the 
emergency-lighting system, and must not block escape-path lighting to 
the extent that the light(s) no longer meet their intended function.
    10. The structure-mounted airbag must not impede occupants' rapid 
exit from the airplane 10 seconds after its deployment.
    11. Where structure-mounted airbag systems are installed in or 
close to passenger evacuation routes (other than for the passenger seat 
for which the airbag is installed), possibility of impact on emergency 
evacuation (e.g., hanging in the aisle, potential trip hazard, etc.) 
must be evaluated.
    12. The airbag electronic system must be designed to be protected 
from lightning per Sec.  25.1316(b), and high-intensity radiated fields 
per Sec.  25.1317(c).
    13. The structure-mounted airbag system must not contain or release 
hazardous quantities of gas or particulate matter into the cabin.
    14. The structure-mounted airbag installation must be protected 
from the effects of fire such that no hazard to occupants will result.
    15. The inflatable bag material must meet the 2.5-inches-per-minute 
horizontal flammability test defined in 14 CFR part 25, appendix F, 
part I, paragraph (a)(1)(iv).
    16. The design of the structure-mounted airbag system must protect 
the mechanisms and controls from external contamination associated with 
that which could occur on or around passenger seating.
    17. The structure-mounted airbag system must have a means to verify 
the integrity of the structure-mounted airbag activation system.
    18. The applicant must provide installation limitations to ensure 
installation compatibility between the seat design and opposing 
monument or structure.

[[Page 14231]]

    Issued in Des Moines, Washington, on January 5, 2021.
Suzanne Masterson,
Manager, Transport Airplane Strategic Policy Section, Policy and 
Innovation Division, Aircraft Certification Service.
[FR Doc. 2021-05308 Filed 3-12-21; 8:45 am]
BILLING CODE 4910-13-P