Proposed Rule2024-29465
Special Conditions: Airbus Model A321 neo ACF and A321 neo XLR Series Airplanes; Dynamic Test Requirements for Single Occupant Oblique Seats at an Installation Angle of 49 Degrees With Airbags and 3-Point Restraint or Pretensioner Restraint Systems
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
December 23, 2024
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
This action proposes special conditions for the Airbus Model A321 neo ACF and A321 neo XLR airplanes. These airplanes 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 a single-occupant oblique seat with an airbag and 3-point or pretensioner restraint system positioned at a 49-degree angle from the cabin centerline. The applicable airworthiness regulations do not contain adequate or appropriate safety standards for this design feature. These proposed 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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[Federal Register Volume 89, Number 246 (Monday, December 23, 2024)]
[Proposed Rules]
[Pages 104455-104459]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2024-29465]
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Proposed Rules
Federal Register
________________________________________________________________________
This section of the FEDERAL REGISTER contains notices to the public of
the proposed issuance of rules and regulations. The purpose of these
notices is to give interested persons an opportunity to participate in
the rule making prior to the adoption of the final rules.
========================================================================
Federal Register / Vol. 89, No. 246 / Monday, December 23, 2024 /
Proposed Rules
[[Page 104455]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. FAA-2024-2570; Notice No. 25-24-05-SC]
Special Conditions: Airbus Model A321 neo ACF and A321 neo XLR
Series Airplanes; Dynamic Test Requirements for Single Occupant Oblique
Seats at an Installation Angle of 49 Degrees With Airbags and 3-Point
Restraint or Pretensioner Restraint Systems
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed special conditions.
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SUMMARY: This action proposes special conditions for the Airbus Model
A321 neo ACF and A321 neo XLR airplanes. These airplanes 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 a single-occupant oblique
seat with an airbag and 3-point or pretensioner restraint system
positioned at a 49-degree angle from the cabin centerline. The
applicable airworthiness regulations do not contain adequate or
appropriate safety standards for this design feature. These proposed
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: Send comments on or before January 13, 2025.
ADDRESSES: Send comments identified by Docket No. FAA-2024-2570 using
any of the following methods:
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.
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
<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: Shannon Lennon, Cabin Safety Section,
AIR-624, Technical Policy Branch, Policy and Standards Division,
Aircraft Certification Service, Federal Aviation Administration, 2200
South 216th Street, Des Moines, WA 98198; telephone (206) 231-3209;
email <a href="/cdn-cgi/l/email-protection#7d2e151c13131213533118131312133d1b1c1c531a120b"><span class="__cf_email__" data-cfemail="77241f1619191819593b12191918193711161659101801">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION:
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 proposed special conditions,
explain the reason for any recommended change, and include supporting
data.
The proposed special conditions address single-occupant oblique
seats with airbags and 3-point restraint or pretensioner restraint
systems at a 49-degree installation angle. The proposed special
conditions substantially align with previously issued conditions
(Special Conditions Nos. 25-811-SC and 25-861-SC) but were adapted to
align with the combination of the novel 49-degree angle installation
along with the potential use of a pretensioner restraint system.
Delivery of these airplanes with this novel or unusual design feature
is currently scheduled for the first quarter of 2025. While the comment
period provided by the FAA for proposed special conditions has
typically been thirty days, the FAA is providing twenty days in this
instance due to the substantive similarity of these conditions with the
terms of previously issued special conditions, and due to the pendency
of the anticipated delivery date for the affected airplane models, per
the criteria in 14 CFR 11.38.
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.
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 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.
Background
On April 6, 2022, Airbus SAS applied for an amendment to Type
Certificate
[[Page 104456]]
No. A28NM for the installation of a single-occupant oblique seat with
an airbag and 3-point or pretensioner restraint system, positioned at a
49-degree angle from the cabin centerline in new Airbus Model A321 neo
ACF and A321 neo XLR airplanes. Airbus Model A321 neo ACF and A321 neo
XLR airplanes, which are derivatives of the Model A321 currently
approved under TC no. A28NM, are twin-engine, transport category
airplanes with a maximum passenger capacity of 244. The maximum takeoff
weight of the Airbus Model A321 neo ACF is approximately 213,848
pounds, while the Airbus Model A321 neo XLR has a maximum takeoff
weight of approximately 222,667 pounds.
Type Certification Basis
Under the provisions of 14 CFR 21.101, Airbus SAS must show that
the Model A321 neo ACF and A321 neo XLR airplanes, as changed, continue
to meet the applicable provisions of the regulations listed in Type
Certificate No. A28NM 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 Airbus Model A321 neo ACF and A321 neo
XLR 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, Airbus Model A321 neo ACF and A321 neo XLR 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
Airbus Model A321 neo ACF and A321 neo XLR airplanes will
incorporate the following novel or unusual design feature: single-
occupant oblique seats with airbag devices and 3-point restraints or a
pretensioner restraint system installed at 49 degrees relative to the
aircraft cabin centerline.
Discussion
Title 14 of the CFR, Sec. 25.785(d) requires that each occupant of
a seat installed at an angle of more than 18 degrees relative to
airplane cabin centerline, must be protected from head injury using a
seatbelt and an energy-absorbing rest that supports the arms,
shoulders, head, and spine, or using a seatbelt and shoulder harness
designed to prevent the head from contacting any injurious object.
The proposed Airbus Model A321 neo ACF and A321 neo XLR airplane's
single occupant oblique seat installation with airbag devices and 3-
point restraint or pretensioner restraint system is novel such that the
current requirements do not adequately address airbag or pretensioner
devices and protection of the occupant's neck, spine, torso, and legs
for seating configurations that are positioned at an angle of 49
degrees from the airplane centerline. The seating configuration
installation angle is beyond the installation-design limits of current
special conditions issued for seat positions at angles between 18
degrees and 45 degrees. At angles greater than 45 degrees, lateral neck
bending and other injury mechanisms prevalent from a fully side-facing
installation become a concern, given the addition of oblique seat
properties. To address these potential injury mechanisms, these special
conditions are based on FAA Policy Statement PS-AIR-25-27, ``Technical
Criteria for Approving Obliques Seats'' as well as Policy Statement PS-
ANM-25-03-R1, ``Technical Criteria for Approving Side-Facing Seats.''
To provide a level of safety equivalent to that afforded to the
occupants of forward and aft-facing seats, new special conditions
containing additional airworthiness standards for dynamic testing
requirements, including both the injury criteria limits from the
oblique-seat policy and the fully side-facing seat policy, are
necessary.
FAA-sponsored research 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
device (ATD) have identified a level of lumbar spinal tension
corresponding to the no-injury impact severity. The FAA has implemented
this spinal tension limit in special conditions for oblique seats. The
spine tension limit selected by the FAA is conservative with respect to
other aviation injury criteria since it corresponds to a no-injury
loading condition.
Other restraint systems, in lieu of single lap belt restrain
systems, have been used to comply with the occupant injury criteria of
Sec. 25.562(c)(5). For instance, shoulder harnesses have been widely
used on flight-attendant seats, flight-deck seats, in business jets,
and in general-aviation airplanes to reduce occupant head injury in the
event of an emergency landing. Special conditions, pertinent
regulations, and published guidance exist that relate to other
restraint systems. However, the use of pretensioners in the restraint
system on transport category airplane seats to comply with the occupant
injury criteria of Sec. 25.562(c)(5) is a novel design.
Pretensioner technology involves a step-change in loading
experienced by the occupant for impacts below and above that at which
the device deploys, because activation of the shoulder harness, at the
point at which the pretensioner engages, interrupts upper-torso
excursion. Such an excursion could result in the head-injury criteria
(HIC) being higher at an intermediate impact condition than that
resulting from the maximum impact condition corresponding to the test
conditions specified in Sec. 25.562. See condition (a)(3) in these
special conditions.
The ideal triangular maximum-severity pulse is defined in Advisory
Circular (AC) 25.562-1B, ``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 pretensioner 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 t<INF>1</INF> is
reached, where t<INF>1</INF> represents the time interval between 0 and
t<INF>1</INF> on the referenced pulse shape, as shown in AC 25.562-1B.
This is an acceptable method of compliance with the test requirements
of the special conditions.
Additionally, the pretensioner might not provide protection, after
actuation, during secondary impacts. Therefore, the case where a small
impact is
[[Page 104457]]
followed by a large impact should be addressed. If the minimum
deceleration severity at which the pretensioner is set to deploy is
unnecessarily low, the protection offered by the pretensioner may be
lost by the time a second, larger impact occurs.
Conditions (a) through (g) address occupant protection in
consideration of the oblique-facing seats. Condition (h) addresses
airbag systems. Conditions (i)(1) through (i)(3) ensure that the
pretensioner system activates when intended and protects a range of
occupants under various accident conditions. Conditions (i)(4) through
(i)(9) address the maintenance and reliability of the pretensioner
system, including any outside influences on the mechanism, to ensure it
functions as intended. Condition (j) addresses general instructions
that supplement these special conditions when tests are required to
assist with test set-ups and appropriate anthropomorphic test dummy
(ATD) selection.
The proposed 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 proposed special conditions are
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 apply to the other 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 Proposed Special Conditions
Accordingly, the Federal Aviation Administration (FAA) proposes the
following special conditions as part of the type certification basis
for Airbus Model A321 neo ACF and A321 neo XLR airplanes.
In addition to the requirements of Sec. Sec. 25.562 and 25.785,
passenger seats with airbag devices and 3-point restraints or
pretensioner restraints installed at an angle 49 degrees from the
aircraft centerline must meet the following conditions:
(a) Head Injury Criteria (HIC)
HIC assessments are required only for head contact with the seat
and other structures.
(1) Compliance with Sec. 25.562(c)(5) is required, except when an
airbag device is present in addition to the 3-point restraint system
and the anthropomorphic test dummy (ATD) has no apparent contact with
the seat and other structure but has contact with the airbag, a HIC
score in excess of 1,000 is acceptable, provided the HIC15 score
(calculated in accordance with 49 CFR 571.208) for that contact is less
than 700.
(2) ATD head contact with the seat or other structure, through the
airbag (if installed), or contact subsequent to contact with the airbag
requires an HIC value not exceeding 1,000.
(3) The HIC value must not exceed 1,000 in any condition in which
the airbag or pretensioner (if installed) does or does not deploy up to
the maximum severity pulse specified by the existing requirements.
(4) To accommodate a range of occupant heights (5th percentile
female to 95th percentile male), any surface, airbag or otherwise, that
provides support for the occupant's head must provide that support in a
consistent manner regardless of occupant stature. Otherwise, additional
HIC assessment tests may be needed.
(b) Body-to-Wall/Furnishing Contact
If a seat is installed aft of a structure, such as an interior wall
or furnishing 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 an occupant could contact. For example,
different yaw angles could result in different injury considerations
and airbag performance, and additional analysis or separate tests may
be necessary to evaluate performance.
(c) Neck Injury Criteria
(1) 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 also reason to
consider that the neck injury potential would be higher for impacts
below the airbag device deployment threshold.
(2) Rotation of the head about its vertical axis, relative to the
torso, is limited to 105 degrees in either direction from forward-
facing.
(3) The neck must not impact any surface that would produce
concentrated loading on the neck.
(4) Assess neck injury for fore and aft neck bending using an FAA
Hybrid III ATD, as described in SAE International (SAE) Technical Paper
1999-01-1609, ``A Lumbar Spine Modification to the Hybrid III ATD for
Aircraft Seat Tests,'' applying the following criteria:
(i) 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:
Fzc = 1,530 lbs (6,805 N) for tension
Fzc = 1,385 lbs (6,160 N) for compression
Myc = 229 lb-ft (301 Nm) in flexion
Myc = 100 lb-ft (136 Nm) in extension
(ii) In addition, peak upper-neck Fz must be below 937 lbs (4,168
N) in tension and 899 lbs (3,999 N) in compression.
(5) When lateral neck bending is present, assess it using an ES-2re
ATD as defined by 49 CFR part 572, subpart U. The data must be filtered
at channel frequency class 600 as defined in SAE Recommended Practice
J211/11, ``Instrumentation for Impact Test Part 1--Electronic
Instrumentation.''
(i) The upper-neck tension force at the occipital condyle (O.C.)
location must be less than 405 lbs (1,800 N).
(ii) The upper-neck compression force at the O.C. location must be
less than 405 lbs (1,800 N).
(iii) The upper-neck bending torque about the ATD x-axis at the
O.C. location must be less than 1,018 in-lbs (115 Nm).
(iv) The upper-neck resultant shear force at the O.C. location must
be less than 186 lbs (825 N).
(d) Spine and Torso Injury Criteria
(1) The seating system must protect the occupant from experiencing
spine and torso injury. The assessment of spine and torso injury must
be conducted with the airbag device activated unless it is necessary to
also consider that the occupant-injury potential would be higher for
impacts below the airbag-device deployment threshold.
(2) Assess spine and torso injury for oblique torso bending using
an FAA Hybrid III ATD, applying the following criteria:
[[Page 104458]]
(i) The lumbar spine tension (Fz) cannot exceed 1,200 lbs (5,338
N).
(ii) 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 Recommended Practice J211/1.
(3) When lateral torso bending is present, assess spine and torso
injury using an ES-2re ATD, applying the following criteria:
(i) Thoracic: The deflection of any of the ES-2re ATD upper,
middle, and lower ribs must not exceed 1.73 inches (44 mm). Process the
data as defined in Federal Motor Vehicle Safety Standards (FMVSS)
571.214, title 49 of the CFR.
(ii) Abdominal: The sum of the measured ES-2re ATD front, middle,
and rear abdominal forces must not exceed 562 lbs (2,500 N). Process
the data as defined in FMVSS 571.214.
(iii) Upper-torso support: The lateral flexion of the ATD torso
must not exceed 40 degrees from the normal upright positions during
impact.
(e) Pelvic Criteria
(1) The seating system must protect the occupant from experiencing
pelvis injury.
(2) 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.
(3) When pelvis contact with the armrest or surrounding interior
components is present, assess it using an ES-2re ATD. The pubic
symphysis force measured by the ES-2re ATD must not exceed 1,350 lbs
(6,000 N). Process the data as defined in FMVSS 571.214.
(f) Femur Criteria
Limit axial rotations of the upper leg (about the z-axis of the
femur, per SAE Recommended Practice J211/1) to 35 degrees from the
nominal seated position. Evaluation during rebound does not need to be
considered.
(g) ATD and Test Condition
(1) Perform longitudinal tests to measure the injury criteria above
using the FAA Hybrid III ATD or the ES-2re ATD. Conduct the tests with
the undeformed floor, at the most critical yaw cases for injury, and
with all lateral structural supports (e.g., armrests or walls)
installed.
(2) For longitudinal tests conducted in accordance with Sec.
25.562(b)(2), show compliance with the seat-strength requirements of
Sec. 25.562(c)(7) and (8), and these special conditions, to ensure
proper loading of the seat by the occupant, the ATD pelvis must remain
supported by the seat pan, and the restraint system must remain on the
pelvis of the ATD until rebound begins. No injury criteria evaluation
is necessary for tests conducted only to assess seat-strength
requirements.
(3) If a seat installation includes adjacent items that are within
contact range of an occupant, assess the injury potential of that
contact. To make this assessment, tests may be conducted to include the
actual contact item, located and attached in a representative fashion.
Alternatively, the injury potential may be assessed through a
combination of tests with contact items having the same geometry as the
actual contact item but having stiffness characteristics that would
create the worst case for injury, such as injuries due to both contact
with the item and lack of support from the item.
(4) Conduct the combined horizontal and vertical test, required by
Sec. 25.562(b)(1) and these special conditions, with a Hybrid II ATD
(49 CFR part 572, subpart B, as specified in Sec. 25.562) or
equivalent.
(5) The design and installation of seat belt buckles must prevent
unbuckling due to applied inertial forces or impact from seat occupant
hands and arms during an emergency landing.
(h) Inflatable Airbag-Restraint System Special Conditions (When
Installed)
An inflatable airbag-restraint system must meet the requirements of
Special Conditions No. 25-375-SC, ``Airbus A318, A319, A320 and A321
Series Airplanes Inflatable Restraints.''
(i) Pretensioner System Special Conditions (When Installed)
(1) Protection During Secondary Impacts:
The pretensioner activation setting must be demonstrated to
maximize the probability of the protection being available when needed,
considering secondary impacts.
(2) Protection of Occupants Other than 50th Percentile:
Protection of occupants for a range of stature from a 2-year-old
child to a 95th percentile male must be shown. For shoulder harnesses
that include pretensioners, protection of occupants other than a 50th
percentile male may be shown by test or analysis. In addition, the
pretensioner must not introduce a hazard to passengers due to the
following seating configurations:
(i) The seat occupant is holding an infant.
(ii) The seat occupant is a child in a child-restraint device.
(iii) The seat occupant is a pregnant woman.
(3) Occupants Adopting the Brace Position:
Occupants in the traditional brace position, when the pretensioner
activates, must not experience adverse effects from the pretensioner
activation.
(4) Inadvertent Pretensioner Actuation:
(i) The probability of inadvertent pretensioner actuation must be
shown to be extremely remote (i.e., average probability per flight hour
of less than 10<SUP>-7</SUP>).
(ii) The system must be shown not susceptible to inadvertent
pretensioner actuation due to wear and tear or inertia loads resulting
from in-flight or ground maneuvers likely to be experienced in service.
(iii) The seated occupant must not be seriously injured due to
inadvertent pretensioner actuation.
(iv) Inadvertent pretensioner activation must not cause a hazard to
the airplane nor cause serious injury to anyone positioned close to the
retractor or belt (e.g., seated in an adjacent seat or standing
adjacent to the seat).
(5) Availability of the Pretensioner Function Before Flight:
The design must provide means for a crewmember to verify the
availability of the pretensioner function before each flight or the
probability of failure of the pretensioner function must be
demonstrated to be extremely remote (i.e., average probability per
flight hour of less than 10-7 between inspection intervals.)
(6) Incorrect Seat Belt Orientation:
The system design must ensure that any incorrect orientation
(twisting) of the seat belt does not compromise the pretensioner
protection function.
(7) Contamination Protection:
The pretensioner mechanisms and controls must be protected from
external contamination that could occur on or around passenger seating.
(8) Prevention of Hazards:
The pretensioner system must not induce a hazard to passengers in
case of fire, nor create a fire hazard if activated.
(9) Functionality After Loss of Power:
The system must function properly after the loss of normal airplane
electrical power and after a transverse separation in the fuselage at
the most critical location. A separation at the location of the system
does not have to be considered.
[[Page 104459]]
(j) General Test Instructions
(1) The appropriate ATD to assess occupant injury (FAA Hybrid III
or ES-2re) will be determined based on the occupant kinematics at the
selected test angle. At the +10 degree yaw angle, the occupant
kinematics show that occupant injury tests using both ATDs may be
required.
(2) Conduct vertical tests with the Hybrid II ATD or equivalent,
with existing pass/fail criteria.
(3) Conduct longitudinal structural tests with the Hybrid II ATD or
equivalent, deformed floor, with 10 degrees yaw, and with all lateral
structural supports (e.g., armrests or walls) required to support the
occupant.
(4) Conduct longitudinal occupant injury tests, as necessary, with
the Hybrid III ATD or ES-2re ATD, or both, undeformed floor, yaw, and
with all lateral structural supports (e.g., armrests or walls)
critically represented which are within the contact range of the
occupant.
(i) Pass/fail injury assessments:
(A) Perform HIC, fore/aft neck injury, spinal tension, and femur
evaluations using an FAA Hybrid III ATD.
(B) Perform lateral neck injury, thoracic, abdominal, pelvis, and
femur evaluations using an ES-2re ATD.
(ii) [Reserved]
(5) For injury assessments accomplished by testing with the ES-2re
ATD for the longitudinal test(s) conducted in accordance with Sec.
25.562(b)(2) and these special conditions, the ATDs must be positioned,
clothed, and have lateral instrumentation configured as follows:
(i) ES-2re ATD Lateral Instrumentation:
The rib-module linear slides are directional (i.e., deflection
occurs in either a positive or negative ATD y-axis direction). Install
the modules such that the moving end of the rib module is toward the
front of the airplane. Install the three abdominal-force sensors so
that they are on the side of the ATD and toward the front of the
airplane.
(ii) ATD Clothing:
Clothe each ATD in form-fitting cotton stretch garments with short
to full-length sleeves, mid-calf to full-length pants, and size 11E
(45) shoes weighing about 2.5 lbs (1.1 kg) and having a heel height of
about 1.5 inches (3.8 cm). The color of the clothing should be in
contrast to the color of the restraint system and the background. The
color of the clothing should be chosen to avoid overexposing the high-
speed images taken during the test. The ES-2re jacket is sufficient for
torso clothing, although a form-fitting shirt may be used if desired.
(iii) ATD Positioning:
(A) Lower the ATD vertically into the seat while simultaneously:
(1) Aligning the midsagittal plane (a vertical plane through the
midline of the body; dividing the body into right and left halves) with
approximately the middle of the seat place.
(2) Keeping the upper legs horizontal by supporting them just
behind the knees.
(3) Applying a horizontal x-axis direction (in the ES-2re ATD
coordinate system) force of about 20 lbs (89 N) to the bottom rib of
the ES-2re to compress the seat back cushion.
(B) After all lifting devices have been removed from the ATD:
(1) Rock it slightly to settle it in the seat.
(2) Bend the knees of the ATD.
(3) Separate the knees by about 4 inches (100 mm).
(4) Set the ATD's head at approximately the midpoint of the
available range of z-axis rotation (to align the head and torso
midsagittal planes).
(5) Position the ATD's arms at the joint's mechanical detent to
position them to an approximately 20 to 40-degree angle with respect to
the torso.
(6) Position the feet such that the centerlines of the lower legs
are approximately parallel.
Issued in Kansas City, Missouri, on December 10, 2024.
Patrick R. Mullen,
Manager, Technical Policy Branch, Policy and Standards Division,
Aircraft Certification Service.
[FR Doc. 2024-29465 Filed 12-20-24; 8:45 am]
BILLING CODE 4910-13-P
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</html>Indexed from Federal Register on December 23, 2024.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.