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.

Proposed Rules Federal Register

104455 

Vol. 89, No. 246 

Monday, December 23, 2024 

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. 

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 

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: 

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 

Shannon.Lennon@faa.gov. 

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 

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. 

Background 

On April 6, 2022, Airbus SAS applied 

for an amendment to Type Certificate 


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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 § 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 § 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 § 11.38, and they become part of 

the type certification basis under 

§ 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, § 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 energyabsorbing 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 SideFacing 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 obliqueseat 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 § 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 § 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 uppertorso 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 § 25.562. See condition 

(a)(3) in these special conditions. 

The ideal triangular maximumseverity 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 t1 is reached, where t1 represents 

the time interval between 0 and t1 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 


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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 

§§ 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 § 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: 


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(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 § 25.562(b)(2), show 

compliance with the seat-strength 

requirements of § 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 

§ 25.562(b)(1) and these special 

conditions, with a Hybrid II ATD (49 

CFR part 572, subpart B, as specified in 

§ 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¥7). 

(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. 


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(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 

§ 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 fulllength 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 highspeed 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 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2024–2667; Project 

Identifier MCAI–2024–00473–T] 

RIN 2120–AA64 

Airworthiness Directives; Deutsche 

Aircraft GmbH (Type Certificate 

Previously Held by 328 Support 

Services GmbH; AvCraft Aerospace 

GmbH; Fairchild Dornier GmbH; 

Dornier Luftfahrt GmbH) Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: The FAA proposes to 

supersede Airworthiness Directive (AD) 

2024–03–07, which applies to all 

Deutsche Aircraft GmbH Model 328–100 

and 328–300 airplanes. AD 2024–03–07 

requires a one-time detailed inspection 

of each affected part, and applicable 

corrective actions. Since the FAA issued 

AD 2024–03–07, the FAA determined 

that repetitive inspections are necessary. 

This proposed AD continues to require 

the actions in AD 2024–03–07 and 

would require repetitive inspections of 

the affected part as specified in a 

European Union Aviation Safety Agency 

(EASA) AD which is proposed for 

incorporation by reference (IBR). The 

FAA is proposing this AD to address the 

unsafe condition on these products. 

DATES: The FAA must receive comments 

on this proposed AD by February 6, 

2025. 

ADDRESSES: You may send comments, 

using the procedures found in 14 CFR 

11.43 and 11.45, by any of the following 

methods: 

• Federal eRulemaking Portal: Go to 

regulations.gov. Follow the instructions 

for submitting comments. 

• Fax: 202–493–2251. 

• Mail: U.S. Department of 

Transportation, Docket Operations, M– 

30, West Building Ground Floor, Room 

W12–140, 1200 New Jersey Avenue SE, 

Washington, DC 20590. 

• Hand Delivery: Deliver to Mail 

address above between 9 a.m. and 5 

p.m., Monday through Friday, except 

Federal holidays. 

AD Docket: You may examine the AD 

docket at regulations.gov under Docket 

No. FAA–2024–2667; or in person at 

Docket Operations between 9 a.m. and 

5 p.m., Monday through Friday, except 

Federal holidays. The AD docket 

contains this NPRM, the mandatory 

continuing airworthiness information 

(MCAI), any comments received, and 

other information. The street address for 

Docket Operations is listed above. 

Material Incorporated by Reference: 

• For EASA material identified in this 

proposed AD, contact EASA, KonradAdenauer-Ufer 3, 50668 Cologne, 

Germany; telephone +49 221 8999 000; 

email ADs@easa.europa.eu; website 

easa.europa.eu. You may find this 

material on the EASA website at 

ad.easa.europa.eu. It is also available at 

regulations.gov under Docket No. FAA– 

2024–2667. 

• You may view this material at the 

FAA, Airworthiness Products Section, 

Operational Safety Branch, 2200 South 

216th St., Des Moines, WA. For 

information on the availability of this 

material at the FAA, call 206–231–3195. 

FOR FURTHER INFORMATION CONTACT: Joe 

Salameh, Aviation Safety Engineer, 

FAA, 1600 Stewart Avenue, Suite 410, 


khammond on DSK9W7S144PROD with PROPOSALS