[Federal Register Volume 84, Number 239 (Thursday, December 12, 2019)]
[Rules and Regulations]
[Pages 67828-67830]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-26722]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. FAA-2019-0851; Special Conditions No. 25-763-SC]
Special Conditions: VT DRB Aviation Consultants, Airbus Model
A330-300 Airplanes; Dynamic Test Requirements for Single-Occupant,
Oblique (Side-Facing) Seats With or Without Airbag Devices or 3-Point
Restraints
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 Model A330-
300 airplane. This airplane, as modified by VT DRB Aviation Consultants
(VT DRB), will have novel or unusual design features when compared to
the state of technology envisioned in the airworthiness standards for
transport-category airplanes. This design feature is single-occupant,
oblique (side-facing) seats 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 VT DRB on December 12, 2019. Send
comments on or before January 27, 2020.
ADDRESSES: Send comments identified by Docket No. FAA-2019-0851 using
any of the following methods:
Federal eRegulations Portal: Go to http://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.
Privacy: The FAA will post all comments it receives, without
change, to http://www.regulations.gov/, including any personal
information the commenter provides. Using the search function of the
docket website, anyone can find and read the electronic form of all
comments received into any FAA docket, including the name of the
individual sending the comment (or signing the comment for an
association, business, labor union, etc.). DOT's complete Privacy Act
Statement can be found in the Federal Register published on April 11,
2000 (65 FR 19477-19478).
Docket: Background documents or comments received may be read at
http://www.regulations.gov/ at any time. Follow the online instructions
for accessing the docket or go to Docket Operations in Room W12-140 of
the West Building Ground Floor at 1200 New Jersey Avenue SE,
Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday,
except Federal holidays.
FOR FURTHER INFORMATION CONTACT: Alan Sinclair, Airframe and Cabin
Safety Section, AIR-675, Transport Standards Branch, Policy and
Innovation Division, Aircraft Certification Service, Federal Aviation
Administration, 2200 South 216th Street, Des Moines, Washington 98198;
telephone and fax 206-231-3215; email [email protected].
SUPPLEMENTARY INFORMATION: The FAA has determined that notice of, and
opportunity for prior public comment on, these special conditions is
impracticable because these procedures would significantly delay
issuance of the design approval and thus delivery of the affected
airplanes.
In addition, 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 has
determined that prior public notice and comment are unnecessary, and
finds that, for the same reason, good cause exists for adopting these
special conditions upon publication in the Federal Register.
Comments Invited
The FAA invites interested people to take part in this rulemaking
by sending written comments, data, or views. The most helpful comments
reference a specific portion of the special conditions, explain the
reason for any recommended change, and include supporting data.
The FAA will consider all comments received by the closing date for
comments. The FAA may change these special conditions based on the
comments received.
Background
On October 12, 2018, VT DRB applied for a supplemental type
certificate for oblique (side-facing) single-occupant seats equipped
with airbag devices or 3-point restraints in Airbus Model A330-300
airplanes. The Airbus Model A330-300 airplane is a twin-engine,
transport-category airplane with a maximum takeoff weight of 533,518
pounds and seating for 297 passengers.
Type Certification Basis
Under the provisions of title 14, Code of Federal Regulations (14
CFR) 21.101, VT DRB must show that the Airbus Model A330-300 airplane,
as changed, continues to meet the applicable provisions of the
regulations listed in Type Certificate No. A46NM or the applicable
regulations in effect on the
[[Page 67829]]
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 A330-300 airplane
because of a novel or unusual design feature, special conditions are
prescribed under the provisions of Sec. 21.16.
Special conditions are initially applicable to the model for which
they are issued. Should the applicant apply for a supplemental type
certificate to modify any other model included on the same type
certificate to incorporate the same novel or unusual design feature,
these special conditions would also apply to the other model under
Sec. 21.101.
In addition to the applicable airworthiness regulations and special
conditions, the Airbus Model A330-300 airplane must comply with the
fuel-vent and 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 A330-300 airplane will incorporate the following
novel or unusual design features:
Single-occupant, oblique (side-facing) seats with airbag devices or
3-point restraints.
Discussion
The FAA has been conducting and sponsoring research on appropriate
injury criteria for oblique (side-facing) seat installations. However,
the FAA research program is not complete and the FAA may update these
criteria as the FAA obtains further research results. To reflect
current research findings, the FAA issued policy statement PS-ANM-25-
03-R1, ``Technical Criteria for Approving Side-Facing Seats,'' November
12, 2012 to update injury criteria for fully side-facing seats, and
policy statement PS-AIR-25-27, ``Technical Criteria for Approving
Oblique Seats,'' July 11, 2018 to define injury criteria for oblique
(side-facing) seats. Refer to these policy statements for definitions
of variables used in the formulae shown in the conditions of this
document.
The installation of these single occupant, oblique (side-facing)
seats is novel given that the Airbus Model A330-300 certification basis
does not adequately address protection of the occupant's neck and spine
for seat configurations that are positioned at an angle greater than 18
degrees from the airplane centerline.
The installation of passenger seats at angles of 18 to 45 degrees
to the airplane centerline is unusual in transport category airplanes
due to the seat and occupant interface with the surrounding furniture
that introduces occupant alignment and loading concerns with or without
the installation of a 3-point or airbag restraint system, or both.
These special conditions are necessary to further address these
potential injuries to the occupant's neck and spine that were not
contemplated in 14 CFR 25.785.
The FAA-sponsored research mentioned earlier has found that an
unrestrained 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. 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 because it
corresponds to a no-injury loading condition.
As noted in the special conditions for the airbag restraint system,
because an airbag restraint system is essentially a single-use device,
the airbag potentially could deploy under crash conditions that are not
sufficiently so severe as to require head-injury protection from the
airbag restraint system. Because 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 the
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.
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 A330-300 airplane as modified by VT DRB. Should VT DRB
apply at a later date for a supplemental type certificate to modify any
other model included on Type Certificate No. A46NM to incorporate the
same novel or unusual design feature, these special conditions would
apply to that model as well.
Conclusion
This action affects only a certain novel or unusual design feature
on one model of airplane. It is not a rule of general applicability and
affects only the applicant who applied to the FAA for approval of these
features on the airplane.
List of Subjects in 14 CFR Part 25
Aircraft, Aviation safety, Reporting and recordkeeping
requirements.
Authority Citation
The authority citation for these special conditions is as follows:
Authority: 49 U.S.C. 106(f), 106(g), 40113, 44701, 44702, 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 Model A330-300 airplanes as
modified by VT DRB.
In addition to the requirements of Sec. 25.562, passenger seats
installed at an angle between 18 degrees and 45 degrees from the
airplane longitudinal centerline must meet the following:
Side-Facing Seats Special Conditions:
1. Head Injury Criteria:
Compliance with Sec. 25.562(c)(5) is required, except that, if the
ATD has no apparent contact with the seat/structure but has contact
with an airbag, a head-injury criterion (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 structure (e.g., an interior wall or
furnishing) that does not provide a homogenous contact surface for the
expected range of occupants and yaw angles, then
[[Page 67830]]
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
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.
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 lb for tension
ii. Fzc = 1385 lb 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 lb in tension
and 899 lb 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 lb.
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: The applicant 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.
Inflatable Airbag Restraint Systems Special Conditions:
If inflatable airbag restraint systems are installed, the airbag
systems must meet the requirements of Airbus Model A330 special
conditions no. 25-395-SC, ``Seats with Inflatable Lapbelts.''
Issued in Des Moines, Washington, on December 6, 2019.
James E. Wilborn,
Acting Manager, Transport Standards Branch, Policy and Innovation
Division, Aircraft Certification Service.
[FR Doc. 2019-26722 Filed 12-11-19; 8:45 am]
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