[Federal Register: November 8, 2004 (Volume 69, Number 215)]
[Rules and Regulations]
[Page 64651-64653]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr08no04-4]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. NM198; Special Conditions No. 25-187A-SC]
Special Conditions: Boeing Model 777 Series Airplanes; Seats With
Inflatable Lapbelts
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final special conditions.
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SUMMARY: These amended special conditions are issued to Boeing
Commercial Airplanes for the Model 777 series airplanes. These
airplanes have a novel or unusual design feature associated with seats
with inflatable lapbelts. Special Conditions No. 25-187-SC were issued
on October 3, 2001, addressing this issue. Boeing subsequently applied
to amend the special conditions to add a new requirement that addresses
the flammability of the material used to construct the inflatable
lapbelt. The applicable airworthiness regulations, including those
contained in Special Conditions No. 25-187-SC, do not contain adequate
or appropriate safety standards for this design feature. The amended
special conditions contain the additional safety standards that the
Administrator considers necessary to establish an appropriate level of
safety considering the safety benefits associated with the inflatable
lapbelt.
DATES: Effective October 29, 2004.
FOR FURTHER INFORMATION CONTACT: Jayson Claar, FAA, Airframe and Cabin
Safety Branch, ANM-115, Transport Airplane Directorate, Aircraft
Certification Service, 1601 Lind Avenue SW., Renton, Washington, 98055-
4056; telephone (425) 227-2194.
SUPPLEMENTARY INFORMATION:
Background
On April 20, 2001, Boeing Commercial Airplanes, P.O. Box 3707,
Seattle, Washington 98124, applied for a type certificate design change
to install inflatable lapbelts for head injury
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protection on certain seats in Boeing Model 777 series airplanes. The
Model 777 series airplane is a swept-wing, conventional-tail, twin-
engine, turbofan-powered transport. The inflatable lapbelt is designed
to limit occupant forward excursion in the event of an accident. This
will reduce the potential for head injury, as determined by the Head
Injury Criteria (HIC) measurement. The inflatable lapbelt behaves
similarly to an automotive airbag, but in this case the airbag is
integrated into the lapbelt, and inflates away from the seated
occupant. While airbags are now standard in the automotive industry,
the use of an inflatable lapbelt is novel for commercial aviation.
Because the existing airworthiness standards of 14 CFR part 25 do
not address inflatable lapbelts, the FAA developed special conditions
to address this design feature. Special Conditions No. 25-187-SC were
issued to Boeing Commercial Airplanes on October 3, 2001, and published
in the Federal Register on October 12, 2001 (66 FR 52017).
On February 26, 2004, The Boeing Company requested that the FAA
amend SC No. 25-187-SC to address flammability of the airbag material.
During the development of the inflatable lapbelt the manufacturer was
unable to develop a fabric that would meet the inflation requirements
for the bag and the flammability requirements of Part I(a)(1)(i) of
appendix F to part 25. The fabrics that were developed that meet the
flammability requirement did not produce acceptable deployment
characteristics. However, the manufacturer was able to develop a fabric
the meets the less stringent flammability requirements of Part
I(a)(1)(iv) of appendix F to part 25 and has acceptable deployment
characteristics.
Discussion
Part I of appendix F to part 25 specifies the flammability
requirements for interior materials and components. There is no
reference to inflatable restraint systems in appendix F because such
devices did not exist at the time the flammability requirements were
written. The existing requirements are based on both material types, as
well as use, and have been specified in light of the state-of-the-art
of materials available to perform a given function. In the absence of a
specific reference, the default requirement would be for the type of
material used to construct the inflatable restraint, which is a fabric
in this case. However, in writing a special condition, the FAA must
also consider the use of the material, and whether the default
requirement is appropriate. In this case, the specialized function of
the inflatable restraint means that highly specialized materials are
needed. The standard normally applied to fabrics is a 12-second
vertical ignition test. However, materials that meet this standard do
not perform adequately as inflatable restraints. Since the safety
benefit of the inflatable restraint is very significant, the
flammability standard appropriate for these devices should not screen
out suitable materials, thereby effectively eliminating use of
inflatable restraints. The FAA will need to establish a balance between
the safety benefit of the inflatable restraint and its flammability
performance. At this time, the 2.5-inch per minute horizontal test is
considered to provide that balance. As the state-of-the-art in
materials progresses (which is expected), the FAA may change this
standard in subsequent special conditions to account for improved
materials.
The additional safety standard is added as Item 14 to existing SC
25-187-SC. Items 1 through 13 are standards already adopted in Special
Conditions No. 25-187-SC.
Type Certification Basis
Under the provisions of Sec. 21.101, Boeing Commercial Airplanes
must show that the Model 777 series airplanes, as changed, continue to
meet the applicable provisions of the regulations incorporated by
reference in Type Certificate No. T00001SE, or the applicable
regulations in effect on the date of application for the change. The
regulations incorporated by reference in the type certificate are
commonly referred to as the ``original type certification basis.'' The
regulations incorporated by reference in Type Certificate No. T00001SE
are as follows: Amendments 25-1 through 25-82 for the Model 777-200,
and amendments 25-1 through 25-86 with exceptions for the Model 777-
300. The U.S. type certification basis for the Model 777 is established
in accordance with Sec. Sec. 21.29 and 21.17 and the type
certification application date. The U.S. type certification basis is
listed in Type Certificate Data Sheet No. T00001SE.
If the Administrator finds that the applicable airworthiness
regulations (i.e., part 25 as amended) do not contain adequate or
appropriate safety standards for Boeing Model 777 series airplanes
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 Boeing Model 777 must comply with the fuel vent and
exhaust emission requirements of part 34 and the noise certification
requirements of part 36.
Special conditions, as defined in Sec. 11.19, are issued in
accordance with Sec. 11.38 and become part of the type certification
basis in accordance with Sec. 21.101.
Applicability
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 or
similar novel or unusual design feature, the special conditions would
also apply to the other model under the provisions of Sec. 21.101.
Discussion of Comments
Notice of proposed amendment of Special Conditions No. 25-187-SC
was published in the Federal Register on September 23, 2004 as Notice
25-04-03-SC (69 FR 56961). We received one comment.
Comment: The commenter states that the special conditions should
address the Model 747, A340, and A380 airplanes as well. As written the
special conditions give the Model 777 a marketing advantage over these
other airplanes that are used in similar markets. The Model 747, A340,
and A380 should have the ability to take advantage of this
functionality until a suitable material is found that addresses the
functionality of the system as well as the 12-second vertical burn
requirements.
FAA Reply: The special conditions are not a rule of general
applicability and therefore cannot be applied to other airplanes such
as the Model 747, A340, and A380. However, should an applicant apply
for certification of an airplane with the same or similar design of
inflatable lapbelts, we would consider that request for a less
stringent flammability requirement for the inflatable bag fabric as
well. We would consider the state-of-the-art inflatable bag fabric at
that time.
Under standard practice, the effective date of final or amended
special conditions would be 30 days after the date of publication in
the Federal Register. However, because delivery of the affected
airplanes with this additional novel or unusual design feature is
imminent, and because a delay would significantly affect the
applicant's installation and type
[[Page 64653]]
certification of the lapbelt, the FAA finds that good cause exists for
making these amended special conditions effective upon issuance.
Conclusion
This action affects only certain novel or unusual design features
on the Boeing Model 777 series airplanes. It is not a rule of general
applicability, and it affects only Model 777 series airplanes listed on
Type Certificate Data Sheet T00001SE.
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(g), 40113, 44701, 44702, 44704.
The Amended Special Conditions
Accordingly, pursuant to the authority delegated to me by the
Administrator, the following amended special conditions are issued as
part of the type certification basis for the Boeing Model 777 series
airplanes with inflatable lapbelts installed.
1. Seats With Inflatable Lapbelts. It must be shown that the
inflatable lapbelt will deploy and provide protection under crash
conditions where it is necessary to prevent serious head injury. The
means of protection must take into consideration a range of stature
from a two-year-old child to a ninety-fifth percentile male. The
inflatable lapbelt must provide a consistent approach to energy
absorption throughout that range. In addition, the following situations
must be considered:
a. The seat occupant is holding an infant.
b. The seat occupant is a child in a child restraint device.
c. The seat occupant is a child not using a child restraint device.
d. The seat occupant is a pregnant woman.
2. The inflatable lapbelt must provide adequate protection for each
occupant regardless of the number of occupants of the seat assembly,
considering that unoccupied seats may have active seatbelts.
3. The design must prevent the inflatable lapbelt from being either
incorrectly buckled or incorrectly installed such that the inflatable
lapbelt would not properly deploy. Alternatively, it must be shown that
such deployment is not hazardous to the occupant and will provide the
required head injury protection.
4. It must be shown that the inflatable lapbelt 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), likely to be experienced in service.
5. Deployment of the inflatable lapbelt must not introduce injury
mechanisms to the seated occupant, or result in injuries that could
impede rapid egress. This assessment should include an occupant who is
in the brace position when it deploys and an occupant whose belt is
loosely fastened.
6. It must be shown that an inadvertent deployment that could cause
injury to a standing or sitting person is improbable.
7. It must be shown that inadvertent deployment of the inflatable
lapbelt during the most critical part of the flight will either not
cause a hazard to the airplane or is extremely improbable.
8. It must be shown that the inflatable lapbelt will not impede
rapid egress of occupants 10 seconds after its deployment.
9. The system must be protected from lightning and HIRF. The
threats specified in Special Condition No. 25-ANM-78 are incorporated
by reference for the purpose of measuring lightning and HIRF
protection. For the purposes of complying with HIRF requirements, the
inflatable lapbelt system is considered a ``critical system'' if its
deployment could have a hazardous effect on the airplane; otherwise it
is considered an ``essential'' system.
10. The inflatable lapbelt must function properly after loss of
normal aircraft electrical power, and after a transverse separation of
the fuselage at the most critical location. A separation at the
location of the lapbelt does not have to be considered.
11. It must be shown that the inflatable lapbelt will not release
hazardous quantities of gas or particulate matter into the cabin.
12. The inflatable lapbelt installation must be protected from the
effects of fire such that no hazard to occupants will result.
13. There must be a means for a crewmember to verify the integrity
of the inflatable lapbelt activation system prior to each flight or it
must be demonstrated to reliably operate between inspection intervals.
14. The inflatable material may not have an average burn rate of
greater than 2.5 inches/minute when tested using the horizontal
flammability test as defined in 14 CFR part 25, appendix F, part I,
paragraph (b)(5).
Issued in Renton, Washington, on October 29, 2004.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 04-24847 Filed 11-5-04; 8:45 am]
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