Rule2024-06196
Special Conditions: Airbus SAS Model A350 Series Airplanes; Seats With Inertia Locking Devices
Primary source
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Published
March 25, 2024
Effective
March 25, 2024
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
These special conditions are issued for the Airbus SAS (Airbus) Model A350 series airplanes. These airplanes will have a novel or unusual design feature when compared to the state of technology envisioned in the applicable airworthiness standards. This design feature is seats with inertia locking devices (ILD). 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.
Full Text
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<title>Federal Register, Volume 89 Issue 58 (Monday, March 25, 2024)</title>
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[Federal Register Volume 89, Number 58 (Monday, March 25, 2024)]
[Rules and Regulations]
[Pages 20543-20545]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2024-06196]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. FAA-2024-0449; Special Conditions No. 25-860-SC]
Special Conditions: Airbus SAS Model A350 Series Airplanes; Seats
With Inertia Locking Devices
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 Airbus SAS
(Airbus) Model A350 series airplanes. These airplanes will have a novel
or unusual design feature when compared to the state of technology
envisioned in the applicable airworthiness standards. This design
feature is seats with inertia locking devices (ILD). 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.
[[Page 20544]]
DATES: This action is effective on Airbus on March 25, 2024. Send
comments on or before May 9, 2024.
ADDRESSES: Send comments identified by Docket No. FAA-2024-0449 using
any of the following methods:
<bullet> Federal eRegulations Portal: Go to <a href="http://www.regulations.gov">www.regulations.gov</a> and
follow the online instructions for sending your comments
electronically.
<bullet> 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.
<bullet> 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.
<bullet> Fax: Fax comments to Docket Operations at 202-493-2251.
<bullet> Docket: Background documents or comments received may be
read at <a href="http://www.regulations.gov">www.regulations.gov</a> 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: Dan Jacquet, Cabin Safety Section,
AIR-624, Technical Policy Branch, Policy & Standards Division, Federal
Aviation Administration, 2200 South 216th Street, Des Moines, WA 98198,
telephone 206-231-3208, email <a href="/cdn-cgi/l/email-protection#2367424d4a464f0d69424052564657634542420d444c55"><span class="__cf_email__" data-cfemail="6f2b0e01060a0341250e0c1e1a0a1b2f090e0e41080019">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION: The substance of these special conditions
has been published in the Federal Register for public comment in
several prior instances with comments received that required no changes
to previously issued special conditions. 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 <a href="http://www.regulations.gov">www.regulations.gov</a>, 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 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 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, and will consider comments filed late if it is possible to do
so without incurring delay. The FAA may change these special conditions
based on the comments received.
Background
On August 16, 2022, Airbus applied for an amendment to Type
Certificate No. T000631B for seats with ILD in the Model A350 series
airplanes. These airplanes are twin-engine, transport-category
airplanes, with a maximum seating for 480 passengers, and a maximum
take-off weight of 623,908 pounds.
Type Certification Basis
Under the provisions of title 14, Code of Federal Regulations (14
CFR) 21.101, Airbus must show that the Airbus Model A350 series
airplanes, as changed, continue to meet the applicable provisions of
the regulations listed in Type Certificate No. T000631B, 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 Airbus Model A350 series airplanes
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 Airbus Model A350 series airplanes 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 Airbus Model A350 series airplanes will incorporate the
following novel or unusual design features:
Seats with inertia locking devices.
Discussion
Airbus will install, in Model A350 series airplanes, passenger
seats that can be translated in the fore and aft direction by an
electrically powered motor (actuator) that is attached to the seat
primary structure. Under typical service-loading conditions, the motor
internal brake is able to translate the seat and hold the seat in the
translated position. However, under the inertial loads of emergency-
landing and loading conditions, specified in Sec. 25.562, the motor
internal brake may not be able to maintain the seat in the required
position. The ILD is an ``active'' device intended to control seat
movement (i.e., a system that mechanically deploys during an impact
event), by locking the gears of the motor assembly in place. The ILD
mechanism is activated by the higher inertial load factors that could
occur during an emergency landing event. Each seat place incorporates
two ILDs, one on either side of the seat pan. Only one ILD is required
to hold an
[[Page 20545]]
occupied seat in position during worst-case dynamic loading specified
in Sec. 25.562.
The ILD will self-activate only in the event of a predetermined
airplane loading condition such as that occurring during crash or
emergency landing and will prevent excessive seat forward translation.
A minimum level of protection must be provided if the seat-locking
device does not deploy.
The normal means of satisfying the structural and occupant
protection requirements of Sec. 25.562 result in a non-quantified, but
nominally predictable, progressive structural deformation or reduction
of injury severity for impact conditions less than the maximum
specified by the rule. A seat using ILD technology, however, may
involve a step change in protection for impacts below and above that at
which the ILD activates and deploys to retain the seat pan in place.
This could result in structural deformation or occupant injury being
higher at an intermediate impact condition than that resulting from the
maximum impact condition. It is acceptable for such step-change
characteristics to exist, provided the resulting output does not exceed
the maximum allowable criteria at any condition at which the ILD does
or does not deploy, up to the maximum severity pulse specified by the
requirements.
The ideal triangular maximum severity pulse is defined in Advisory
Circular (AC) 25.561-1B ``Dynamic Evaluation of Seat Restraint Systems
and Occupant Protection on Transport Airplanes''. For the evaluation
and testing of less-severe pulses for purposes of assessing the
effectiveness of the ILD deployment setting, a similar triangular pulse
should be used with acceleration, rise time, and velocity change scaled
accordingly. The magnitude of the required pulse should not deviate
below the ideal pulse by more than 0.5g until 1.33 t1 is reached, where
t1 represents the time interval between 0 and t1 on the referenced
pulse shape as shown in AC 25.561-1B. This is an acceptable method of
compliance to the test requirements of the special conditions.
Conditions 1 through 5 ensure that the ILD activates when intended,
to provide the necessary protection of occupants. This includes
protection of a range of occupants under various accident conditions.
Conditions 6 through 10 address maintenance and reliability of the ILD,
including any outside influences on the mechanism, to ensure it
functions as intended.
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
Airbus Model A350 series airplanes. Should Airbus 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 a certain novel or unusual design feature
on one model series of airplanes. 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, and
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 Airbus SAS Model A350 series
airplanes.
In addition to the requirements of Sec. 25.562, passenger seats
incorporating inertia locking devices (ILD)s must meet the following:
1. Level of Protection Provided by ILD--It must be demonstrated by
test that the seats and attachments, when subject to the emergency-
landing dynamic conditions specified in Sec. 25.562, and with one ILD
not deployed, do not experience structural failure that could result
in:
a. Separation of the seat from the airplane floor.
b. Separation of any part of the seat that could form a hazard to
the seat occupant or any other airplane occupant.
c. Failure of the occupant restraint or any other condition that
could result in the occupant separating from the seat.
2. Protection Provided Below and Above the ILD Actuation
Condition--If step-change effects on occupant protection exist for
impacts below and above that at which the ILD deploys, tests must be
performed to demonstrate that the occupant is shown to be protected at
any condition at which the ILD does or does not deploy, up to the
maximum severity pulse specified by Sec. 25.562. Test conditions must
take into account any necessary tolerances for deployment.
3. Protection Over a Range of Crash Pulse Vectors--The ILD must be
shown to function as intended for all test vectors specified in Sec.
25.562.
4. Protection During Secondary Impacts--The ILD activation setting
must be demonstrated to maximize the probability of the protection
being available when needed, considering a secondary impact that is
above the severity at which the device is intended to deploy up to the
impact loading required by Sec. 25.562.
5. Protection of Occupants other than 50th Percentile--Protection
of occupants for a range of stature from a two-year-old child to a
ninety-five-percentile male must be shown.
6. Inadvertent Operation--It must be shown that any inadvertent
operation of the ILD does not affect the performance of the device
during a subsequent emergency landing.
7. Installation Protection--It must be shown that the ILD
installation is protected from contamination and interference from
foreign objects.
8. Reliability--The performance of the ILD must not be altered by
the effects of wear, manufacturing tolerances, aging, or drying of
lubricants, and corrosion.
9. Maintenance and Functional Checks--The design, installation, and
operation of the ILD must be such that it is possible to functionally
check the device in place. Additionally, a functional-check method and
a maintenance-check interval must be included in the seat installer's
instructions for continued airworthiness (ICA) document.
10. Release Function--If a means exists to release an inadvertently
activated ILD, the release means must not introduce additional hidden
failures that would prevent the ILD from functioning properly.
Issued in Kansas City, Missouri, on March 19, 2024.
James David Foltz,
Manager, Technical Policy Branch, Policy and Standards Division,
Aircraft Certification Service.
[FR Doc. 2024-06196 Filed 3-22-24; 8:45 am]
BILLING CODE 4910-13-P
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</html>Indexed from Federal Register on March 25, 2024.
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