Rule2024-06894
Special Conditions: Jet Aviation AG, The Boeing Company Model 737-8 Series Airplane; Dynamic Test Requirements for Single Occupant Oblique Seats With or Without Airbags and/or 3-Point Restraints
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Published
April 4, 2024
Effective
April 4, 2024
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
These special conditions are issued for The Boeing Company (Boeing) Model 737-8 series airplane. This airplane, as modified by Jet Aviation AG (Jet Aviation), 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 oblique (side-facing) single-occupant seats equipped with airbag devices or 3-point restraints. 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 66 (Thursday, April 4, 2024)</title>
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[Federal Register Volume 89, Number 66 (Thursday, April 4, 2024)]
[Rules and Regulations]
[Pages 23504-23507]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2024-06894]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. FAA-2024-0448; Special Conditions No. 25-859-SC]
Special Conditions: Jet Aviation AG, The Boeing Company Model
737-8 Series Airplane; Dynamic Test Requirements for Single Occupant
Oblique Seats With or Without Airbags and/or 3-Point Restraints
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final special conditions; request for comments.
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[[Page 23505]]
SUMMARY: These special conditions are issued for The Boeing Company
(Boeing) Model 737-8 series airplane. This airplane, as modified by Jet
Aviation AG (Jet Aviation), 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 oblique (side-facing) single-occupant seats equipped with
airbag devices or 3-point restraints. 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 Jet Aviation on April 4, 2024. Send
comments on or before May 20, 2024.
ADDRESSES: Send comments identified by Docket No. FAA-2024-0448 using
any of the following methods:
<bullet> Federal eRegulations Portal: Go to <a href="https://www.regulations.gov/">https://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="https://www.regulations.gov/">https://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: John Shelden, Cabin Safety Section,
AIR-624, Technical Policy Branch, Policy and Standards Division,
Aircraft Certification Service, Federal Aviation Administration, 2200
South 216th Street, Des Moines, Washington 98198; telephone and fax
206-231-3214; email <a href="/cdn-cgi/l/email-protection#ffb5909791d1ac979a939b9a91bf999e9ed1989089"><span class="__cf_email__" data-cfemail="43092c2b2d6d102b262f27262d032522226d242c35">[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 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 <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 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, 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 December 19, 2022, Jet Aviation applied for a supplemental type
certificate for the installation of oblique (side-facing) passenger
seats with or without airbag devices or 3-point restraints in the
Boeing Model 737-8 series airplanes. The Boeing Model 737-8 series
airplane is a twin-engine, transport category airplane with a maximum
takeoff weight of approximately 182,200 lbs. The airplane, as modified
by Jet Aviation, will have a maximum seating capacity of 32.
Type Certification Basis
Under the provisions of title 14, Code of Federal Regulations (14
CFR) 21.101, Jet Aviation must show that the Model 737-8 series
airplanes, as changed, continue to meet the applicable provisions of
the regulations listed in Type Certificate No. A16WE 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 (i.e., 14 CFR part 25) do not contain adequate or
appropriate safety standards for the Boeing Model 737-8 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 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 under Sec. 21.101.
In addition to the applicable airworthiness regulations and special
conditions, the Boeing Model 737-8 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 737-8 series airplane, as modified by Jet
Aviation,
[[Page 23506]]
will incorporate a seating configuration that is novel or unusual due
to the installation of oblique (side-facing) passenger seats and
surrounding furniture that introduces occupant alignment and loading
concerns. These oblique seats may be installed at an angle of 18 to 45
degrees to the aircraft centerline and may include a 3-point restraint
system and/or airbags, for occupant restraint and injury protection.
Discussion
Title 14, Code of Federal Regulations (14 CFR) 25.785(d) requires
that each occupant of a seat that makes more than an 18 degree angle
with the vertical plane containing the airplane centerline must be
protected from head injury by a safety belt and an energy absorbing
rest that will support the arms, shoulders, head, and spine, or by a
safety belt and shoulder harness that will prevent the head from
contacting any injurious object.
The proposed Boeing Model 737-8 airplane seat installation is novel
in that the current requirements do not adequately address protection
of the occupant's neck and spine for seating configurations that are
positioned at angles greater than 18 degrees up to and including 45
degrees from the airplane centerline. The installation of passenger
seats at angles of 18 to 45 degrees to the airplane centerline is
unique due to the seat/occupant interface with the surrounding
furniture that introduces occupant alignment/loading concerns with or
without the installation of a 3-point or airbag restraint system, or
both.
In order to provide a level of safety that is equivalent to that
afforded to occupants of forward and aft facing seating, additional
airworthiness standards, in the form of new special conditions, are
necessary.
The FAA has been conducting and sponsoring research on appropriate
injury criteria for oblique (side-facing) seat installations. To
reflect current research findings, the FAA issued Policy Statement PS-
AIR-25-27. FAA-sponsored research has found that an un-restrained
flailing of the upper torso, even when the pelvis and torso are nearly
aligned, can produce serious spinal and torso injuries. At lower impact
severities, even with significant misalignment between the torso and
pelvis, these injuries did not occur. Tests with an FAA H-III
anthropomorphic test dummy (ATD) have identified a level of lumbar
spinal tension corresponding to the no-injury impact severity. This
level of tension is included as a limit in the special conditions. The
spine tension limit selected is conservative with respect to other
aviation injury criteria since it corresponds to a no-injury loading
condition.
As noted in the special conditions, because each airbag restraint
system is essentially a single use device, there is the potential that
it could deploy under crash conditions that are not sufficiently severe
as to require head injury protection from the airbag restraint system.
Since an actual crash is frequently composed of a series of impacts
before the airplane comes to rest, this could render the airbag
restraint system useless if a larger impact follows the initial impact.
This situation does not exist with energy absorbing pads or upper torso
restraints, which tend to provide protection according to the severity
of the impact. Therefore, the installation of the airbag restraint
system should be such that the airbag restraint system will provide
protection when it is required and will not expend its protection when
it is not needed.
Because these airbag restraint systems may or may not activate
during various crash conditions, the injury criteria listed in these
special conditions and in Sec. 25.562 must be met in an event that is
slightly below the activation level of the airbag restraint system. If
an airbag restraint system is included with the oblique seats, the
system must meet the requirements in one of the airbag (inflatable
restraint) special conditions applicable to the Boeing Model 737 series
airplanes. These special conditions supplement part 25 and, more
specifically, supplement Sec. Sec. 25.562 and 25.785.
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 737-8 series airplane modified by Jet Aviation. Should Jet
Aviation apply at a later date for a supplemental type certificate to
modify any other model included on Type Certificate No. A16WE to
incorporate the same novel or unusual design feature, or should Jet
Aviation apply for a change to the supplemental type certificate to
include another model 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 series 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 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
[squf] 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 Boeing Company Model 737-8
series airplanes modified by Jet Aviation AG.
In addition to the requirements of Sec. 25.562, passenger seats
installed at an angle between 18 degrees and 45 degrees from the
aircraft centerline must meet the following:
1. Head Injury Criteria (HIC)
Compliance with Sec. 25.562(c)(5) is required, except that, if the
anthropomorphic test dummy (ATD) has no apparent contact with the seat/
structure but has contact with an airbag, a HIC unlimited score in
excess of 1000 is acceptable, provided the HIC15 score (calculated in
accordance with 49 CFR 571.208) for that contact is less than 700.
2. Body-to-Wall/Furnishing Contact
If a seat is installed aft of a structure (e.g., interior wall or
furnishings) that does not provide a homogenous contact surface for the
expected range of occupants and yaw angles, then additional analysis
and tests may be required to demonstrate that the injury criteria are
met for the area that an occupant could contact. For example, if
different yaw angles could result in different airbag device
performance, then additional analysis or separate tests may be
necessary to evaluate performance.
3. Neck Injury Criteria
The seating system must protect the occupant from experiencing
serious neck injury. The assessment of neck injury must be conducted
with the airbag device activated, unless there is reason to also
consider that the neck-injury potential would be higher for impacts
below the airbag-device deployment threshold.
[[Page 23507]]
a. The Nij (calculated in accordance with 49 CFR 571.208) must be
below 1.0, where Nij = Fz/Fzc + My/Myc, and Nij critical values are:
i. Fzc = 1530 lbs. for tension
ii. Fzc = 1385 lbs. for compression
iii. Myc = 229 lb-ft in flexion
iv. Myc = 100 lb-ft in extension
b. In addition, peak Fz must be below 937 lbs. in tension and 899
lbs. in compression.
c. Rotation of the head about its vertical axis relative to the
torso is limited to 105 degrees in either direction from forward
facing.
d. The neck must not impact any surface that would produce
concentrated loading on the neck.
4. Spine and Torso Injury Criteria
a. The lumbar spine tension (Fz) cannot exceed 1200 lbs.
b. Significant concentrated loading on the occupant's spine, in the
area between the pelvis and shoulders during impact, including rebound,
is not acceptable. During this type of contact, the interval for any
rearward (X direction) acceleration exceeding 20g must be less than 3
milliseconds as measured by the thoracic instrumentation specified in
49 CFR part 572, subpart E filtered in accordance with SAE
International (SAE) recommended practice J211/1, ``Instrumentation for
Impact Test--Part 1--Electronic Instrumentation.''
c. The occupant must not interact with the armrest or other seat
components in any manner significantly different than would be expected
for a forward-facing seat installation.
5. Pelvis Criteria
Any part of the load-bearing portion of the bottom of the ATD
pelvis must not translate beyond the edges of the seat bottom seat-
cushion supporting structure.
6. Femur Criteria
Axial rotation of the upper leg (about the z-axis of the femur per
SAE Recommended Practice J211/1) must be limited to 35 degrees from the
nominal seated position. Evaluation during rebound does not need to be
considered.
7. ATD and Test Conditions
Longitudinal tests conducted to measure the injury criteria above
must be performed with the FAA Hybrid III ATD, as described in SAE
1999-01-1609, ``A Lumbar Spine Modification to the Hybrid III ATD for
Aircraft Seat Tests.'' The tests must be conducted with an undeformed
floor, at the most-critical yaw cases for injury, and with all lateral
structural supports (e.g., armrests or walls) installed.
Note: Jet Aviation AG must demonstrate that the installation of
seats via plinths or pallets meets all applicable requirements.
Compliance with the guidance contained in Policy Memorandum PS-ANM-
100-2000-00123, ``Guidance for Demonstrating Compliance with Seat
Dynamic Testing for Plinths and Pallets,'' dated February 2, 2000,
is acceptable to the FAA.
8. Inflatable Airbag Restraint Systems Special Conditions
If inflatable airbag restraint systems are installed, the airbag
systems must meet the requirements in Special Conditions 25-386-SC, or
other airbag system special conditions which are applicable to the
Boeing Model 737 series airplanes.
Issued in Kansas City, Missouri, on March 22, 2024.
Patrick R. Mullen,
Manager, Technical Policy Branch, Policy and Standards Division,
Aircraft Certification Service.
[FR Doc. 2024-06894 Filed 4-3-24; 8:45 am]
BILLING CODE 4910-13-P
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