[Federal Register Volume 90, Number 182 (Tuesday, September 23, 2025)]
[Rules and Regulations]
[Pages 45659-45661]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-18359]
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Rules and Regulations
Federal Register
________________________________________________________________________
This section of the FEDERAL REGISTER contains regulatory documents
having general applicability and legal effect, most of which are keyed
to and codified in the Code of Federal Regulations, which is published
under 50 titles pursuant to 44 U.S.C. 1510.
The Code of Federal Regulations is sold by the Superintendent of Documents.
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Federal Register / Vol. 90, No. 182 / Tuesday, September 23, 2025 /
Rules and Regulations
[[Page 45659]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. FAA-2025-2416; Special Conditions No. 25-884-SC]
Special Conditions: H4 Aerospace (UK) Ltd, The Boeing Company
Model 757-200 Series Airplane; Seats With Non-Traditional, Large, Non-
Metallic Panels
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 Boeing Company
(Boeing) Model 757-200 series airplane. This airplane, as modified by
H4 Aerospace (UK) Ltd (H4 Aerospace), will have a novel or unusual
design feature when compared to the state of technology envisioned in
the airworthiness standards. This design feature is associated with
seats that include non-traditional, large, non-metallic panels. 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: This action is effective on H4 Aerospace on September 23, 2025.
Send comments on or before November 7, 2025.
ADDRESSES: Send comments identified by Docket No. FAA-2025-2416 using
any of the following methods:
Federal eRegulations Portal: Go to 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.
Docket: Background documents or comments received may be read at
www.regulations.gov at any time. Follow the online instructions for
accessing the docket or go 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.
FOR FURTHER INFORMATION CONTACT: Alan Sinclair, Cabin Safety, AIR-624,
Technical Policy Branch, Policy and Standards Division, Aircraft
Certification Service, Federal Aviation Administration, 2200 South
216th Street, Des Moines, Washington 98198; telephone (206) 231-3215;
email [email protected].
SUPPLEMENTARY INFORMATION: The FAA has published substantially
identical special conditions in the Federal Register for public comment
in several prior instances with no substantive comments received.
Therefore, the FAA finds, pursuant to 14 CFR 11.38(b), that new
comments are unlikely, and notice and comment prior to this publication
are unnecessary.
Privacy
Except for Confidential Business Information (CBI) as described in
the following paragraph, and other information as described in title
14, Code of Federal Regulations (14 CFR) 11.35, the FAA will post all
comments received without change to www.regulations.gov, including any
personal information you provide. The FAA will also post a report
summarizing each substantive verbal contact received about these
special conditions.
Confidential Business Information
Confidential Business Information (CBI) is commercial or financial
information that is both customarily and actually treated as private by
its owner. Under the Freedom of Information Act (FOIA) (5 U.S.C. 552),
CBI is exempt from public disclosure. If your comments responsive to
these special conditions contain commercial or financial information
that is customarily treated as private, that you actually treat as
private, and that is relevant or responsive to these special
conditions, it is important that you clearly designate the submitted
comments as CBI. Please mark each page of your submission containing
CBI as ``PROPIN.'' The FAA will treat such marked submissions as
confidential under the FOIA, and the indicated comments will not be
placed in the public docket of these proposed special conditions. Send
submissions containing CBI to the individual listed in the For Further
Information Contact section above. Comments the FAA receives, which are
not specifically designated as CBI, will be placed in the public docket
for these proposed special conditions.
Comments Invited
The FAA invites 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.
The FAA will consider all comments received by the closing date for
comments. The FAA may change these special conditions based on the
comments received.
Background
On September 3, 2021, H4 Aerospace (UK) Ltd applied for a
supplemental type certificate for installing seats that include non-
traditional, large, non-metallic panels in a Boeing 757-200 series
airplane. The Boeing Model 757-200 series airplane, currently approved
under Type Certificate No. A2NM, is a twin-engine transport category
airplane, with seating provisions for up to 239 passengers and a
maximum take-off weight of 220,000 pounds.
Type Certification Basis
Under the provisions of title 14, Code of Federal Regulations (14
CFR) 21.101, H4 Aerospace must show that the Boeing Model 757-200
series airplane, as changed, continues to meet the applicable
provisions of the regulations listed in Type Certificate No. A2NM or
[[Page 45660]]
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 757-200 series
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 applicant apply for a supplemental type
certificate to modify any other model included on the same type
certificate 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 757-200 series airplane must comply with
the 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 757-200 series airplane will incorporate the
following novel or unusual design feature:
Seats that incorporate non-traditional, large, non-metallic panels
in lieu of the traditional metal frame covered by fabric.
Discussion
In the early 1980s, the FAA conducted extensive research on the
effects of post-crash flammability in the passenger cabin. As a result
of this research and service experience, the FAA adopted new standards
for interior surfaces associated with large surface-area parts.
Specifically, the rules require measurement of heat release and smoke
emission (part 25, Appendix F, parts IV and V) for the affected parts.
Heat release has been shown to have a direct correlation with post-
crash fire-survival time. Materials that comply with the standards
(i.e., Sec. 25.853 entitled ``Compartment interiors'' as amended by
Amendment 25-61 and Amendment 25-66) extend survival time by
approximately two minutes over materials that do not comply.
At the time these standards were written, the potential application
of the requirements of heat release and smoke emission to seats was
explored. The seat frame itself was not a concern because it was
primarily made of aluminum and included only small amounts of non-
metallic materials. The FAA determined that the overall effect of these
materials on survivability was negligible, whether or not the non-
metallic materials met the heat-release and smoke-emission
requirements. The requirements, therefore, did not address seats. The
preambles to both the Notice of Proposed Rule Making (NPRM) No. 85-10
(50 FR 15038, April 16, 1985), and the Final Rule at Amendment 25-61
(51 FR 26206, July 21, 1986), specifically note that seats were
excluded because the recently-adopted standards for flammability of
seat cushions will greatly inhibit involvement of the seats in a cabin
fire.
Subsequently, the Final Rule at Amendment 25-83 (60 FR 6615, March
6, 1995) clarified the definition of minimum panel size: ``It is not
possible to cite a specific size that will apply in all installations;
however, as a general rule, components with exposed-surface areas of
one square foot or less may be considered small enough that they do not
have to meet the new standards. Components with exposed-surface areas
greater than two square feet may be considered large enough that they
do have to meet the new standards. Those with exposed-surface areas
greater than one square foot, but less than two square feet, must be
considered in conjunction with the areas of the cabin in which they are
installed before a determination could be made.''
On October 17, 1997, the FAA issued Policy Memorandum PS-ANM100-97-
112-39, ``Guidance for Flammability Testing of Seat/Console
Installations,'' (https://drs.faa.gov/browse). That memo was issued
when it became clear that seat designs were evolving to include large,
non-metallic panels with surface areas that would impact survivability
during a cabin fire event, comparable to partitions or galleys. The
memo noted that large-surface-area panels must comply with heat-release
and smoke-emission requirements, even if they were attached to a seat.
If the FAA had not issued such policy, seat designs could have been
viewed as a loophole to the airworthiness standards that would result
in an unacceptable decrease in survivability during a cabin fire event.
In October 2004, the FAA focused attention on the appropriate
flammability standards for passenger seats that incorporated non-
traditional, large, non-metallic panels in lieu of the traditional
fabric-covered metal. The FAA reviewed this design and determined that
it represented the kind and quantity of material that should be
required to pass the heat-release and smoke-emissions requirements. The
FAA determined that special conditions would be issued to apply the
standards defined in Sec. 25.853(d) to seats designed with large, non-
metallic panels.
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.
Applicability
As discussed above, these special conditions are applicable to the
Boeing Model 757-200 series airplane as modified by H4 Aerospace.
Should H4 Aerospace apply at a later date for a supplemental type
certificate to modify any other model included on Type Certificate No.
A2NM to incorporate the same novel or unusual design feature, these
special conditions would apply to that model as well.
Conclusion
This action affects only a certain novel or unusual design feature
on one model of airplane. 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 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), 40113, 44701, 44702, and 44704.
The Special Conditions
[ssquf] 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 757 series airplanes
modified by H4 Aerospace (UK) Ltd.
1. Except as provided in paragraph 3 of these special conditions,
compliance with 14 CFR part 25, Appendix F, parts IV and V, heat
release and smoke emission, is required for seats that incorporate non-
traditional, large, non-metallic panels that may either be a single
component or multiple components in a concentrated area in their
design.
2. The applicant may designate up to and including 1.5 square feet
of non-traditional, non-metallic panel material per seat place that
does not have to comply with special condition (1). A
[[Page 45661]]
triple-seat assembly may have a total of 4.5 square feet excluded on
any portion of the assembly (e.g., outboard-seat place 1 square foot;
middle, 1 square foot; and inboard, 2.5 square feet).
3. Seats do not have to meet the test requirements of 14 CFR part
25, Appendix F, parts IV and V, when installed in compartments that are
not otherwise required to meet these requirements.
Issued in in Kansas City, Missouri, on September 18, 2025.
Patrick R. Mullen,
Manager, Technical Policy Branch, Policy and Standards Division,
Aircraft Certification Service.
[FR Doc. 2025-18359 Filed 9-22-25; 8:45 am]
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