[Federal Register Volume 81, Number 149 (Wednesday, August 3, 2016)]
[Rules and Regulations]
[Pages 51084-51086]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-18323]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. FAA-2016-4136; Special Conditions No. 25-621-SC]
Special Conditions: The Boeing Company Model 777-300ER Airplanes;
Dynamic Test Requirements for Single-Occupant Oblique (Side-Facing)
Seats with Inflatable Restraints
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final special conditions; request for comments.
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SUMMARY: These special conditions are issued to The Boeing Company
(Boeing) for their Model 777-300ER airplane. This airplane has novel or
unusual design features associated with single-occupant oblique (side-
facing) seats equipped with inflatable restraints. The applicable
airworthiness regulations do not contain adequate or appropriate safety
standards for occupants of seats installed at an angle of greater than
18 degrees, but substantially less than 90 degrees, to the vertical
plane containing the centerline of the airplane, nor for inflatable
restraints or related airbag devices. 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 Boeing on August 3, 2016. We must
receive your comments by September 19, 2016.
ADDRESSES: Send comments identified by docket number FAA-2016-4136
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 Web site, 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), as well as at http://DocketsInfo.dot.gov/.
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: John Shelden, Airframe and Cabin
Safety, ANM-115, Transport Airplane Directorate, Aircraft Certification
Service, 1601 Lind Avenue SW., Renton, Washington 98057-3356; telephone
425-227-2785; facsimile 425-227-1149.
SUPPLEMENTARY INFORMATION: The FAA has determined that notice of, and
opportunity for prior public comment on, these special conditions are
impracticable because these procedures would significantly delay
issuance of the design approval and thus delivery of the affected
airplane. In addition, the substance of these special conditions has
been subject to the public-comment process in several prior instances
with no substantive comments received.
The FAA therefore finds that good cause exists for making these
special conditions effective upon publication in the Federal Register.
Comments Invited
We invite 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.
We will consider all comments we receive by the closing date for
comments. We may change these special conditions based on the comments
we receive.
Background
On December 24, 2015, Boeing Commercial Airplanes applied for a
design change to type certificate no. T00001SE for single-occupant
seats installed at an oblique angle to the vertical plane containing
the centerline of the airplane, and equipped with inflatable lapbelts,
in the Boeing Model 777-300ER airplane. The Model 777-300ER airplane is
a wide body, swept wing, conventional tail, twin-engine, turbofan-
powered, transport-category airplane.
Type Certification Basis
The type certification basis for the Model 777-300ER airplane is 14
CFR part 25, effective February 1, 1965, as amended by Amendments 25-1
through 25-98, including special conditions 25-295-SC, 25-187A-SC, and
25-569-SC. In addition, the certification basis includes certain
special conditions, exemptions, or later amended sections of the
applicable part that are not relevant to these proposed special
conditions.
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 777-300ER airplane
because of a novel or unusual
[[Page 51085]]
design feature, special conditions are prescribed under the provisions
of Sec. 21.16.
Under the provisions of title 14, Code of Federal Regulations (14
CFR) 21.101, Boeing must show that the Model 777-300ER airplane, as
changed, continues to meet the applicable provisions of the regulations
listed in type certificate no. T00001SE or the applicable regulations
in effect on the date of application for the change, except for earlier
amendments as agreed upon by the FAA. These regulations will be
incorporated into type certificate no. T00001SE after type
certification approval of the 777-300ER.
In addition to the applicable airworthiness regulations and special
conditions, the Boeing Model 777-300ER 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 Boeing Model 777-300ER airplane will incorporate the following
novel or unusual design features:
The seating configuration proposed by Boeing in certification plan
no. 17174, revision A, ``Installation of B/E Aerospace Super-Diamond
Model Business Class Seats on WE736,'' consists of Super Diamond model
oblique (side-facing), business-class passenger seats installed in a
Boeing Model 777-300ER airplane. These seats will also incorporate
inflatable restraints.
The applicable airworthiness regulations do not contain adequate or
appropriate safety standards for occupants of seats installed in the
proposed configuration. To provide a level of safety equivalent to that
afforded to occupants of forward- and aft-facing seats, additional
airworthiness standards, in the form of special conditions, are
necessary. Although special conditions no. 25-187A-SC, 25-295-SC, and
25-569-SC already apply to the 777-300ER, they do not directly address
the complex occupant-loading conditions introduced by this oblique
(side-facing) seat configuration, nor do they reflect the latest
findings of on-going research.
Discussion
Amendment 25-15 to part 25, dated October 24, 1967, introduced the
subject of side-facing seats, and a requirement that each occupant in a
side-facing seat must be protected from head injury by a safety belt
and a cushioned rest that will support the arms, shoulders, head, and
spine.
Subsequently, Amendment 25-20, dated April 23, 1969, clarified the
definition of side-facing seats to require that each occupant of a seat
that is positioned at more than an 18-degree angle to the vertical
plane containing the airplane centerline must be protected from head
injury by a safety belt and an energy-absorbing rest that supports the
arms, shoulders, head, and spine; or by a safety belt and shoulder
harness that prevents the head from contacting injurious objects. The
FAA concluded that a maximum 18-degree angle would provide an adequate
level of safety based on tests that were performed at the time, and
thus adopted that standard.
Amendment 25-64, dated June 16, 1988, revised the emergency-landing
conditions that must be considered in the design of the airplane. It
revised the static-load conditions in Sec. 25.561 and added a new
Sec. 25.562, requiring dynamic testing for all seats approved for
occupancy during takeoff and landing. The intent was to provide an
improved level of safety for occupants on transport-category airplanes.
Because most seating on transport-category airplanes is forward-facing,
the pass/fail criteria developed in Amendment 25-64 focused primarily
on forward-facing seats. Therefore, the testing specified in the rule
did not provide a complete measure of occupant injury in seats that are
not forward-facing. However, Sec. 25.785 does require that occupants
of all seats occupied during taxi, takeoff, and landing not suffer
serious injury as a result of the inertia forces specified in
Sec. Sec. 25.561 and 25.562.
To address recent research findings and accommodate commercial
demand, the FAA developed a methodology to address all fully side-
facing seats (i.e., seats oriented in the airplane with the occupant
facing 90 degrees to the direction of airplane travel) and has
documented those requirements in a set of proposed new special
conditions. The FAA issued policy statement PS-ANM-25-03-R1 on November
12, 2012, titled, ``Technical Criteria for Approving Side-Facing
Seats,'' which conveys the injury criteria to be used in the special
conditions. Some of those criteria are applicable to oblique seats, but
others are not because the motion of an occupant in an oblique seat is
different from the motion of an occupant in a fully side-facing seat
during emergency-landing conditions.
For shallower installation angles, the FAA has granted equivalent
level of safety (ELOS) findings for oblique seat installations on the
premise that an occupant's kinematics in an oblique seat during a
forward impact would result in the body aligning with the impact
direction. We predicted that the occupant response would be similar to
an occupant of a forward-facing seat, and would produce a level of
safety equivalent to that of a forward-facing seat. These ELOS findings
were subject to many conditions that reflected the injury-evaluation
criteria and mitigation strategies available at the time of issuance of
the ELOS. However, review of dynamic test results for many of these
oblique seat installations raised concerns that the premise was not
correct. Potential injury mechanisms exist that are unique to oblique
seats and are not mitigated by the ELOS self-alignment approach even if
the occupant appears to respond similarly to a forward-facing seat.
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 777-300ER airplane. These special conditions can be
applied to oblique seats installed in accordance with Boeing
certification plan no. 17174, revision A, ``Installation of B/E
Aerospace Super-Diamond Business Class Seats on WE736.''
The FAA will amend these special conditions, or issue new special
conditions, should unusual occupant response in the required dynamic
tests, or additional research into occupant-injury mechanisms, indicate
that these special conditions are inadequate. Any future special
conditions would include due public notice for comment.
Conclusion
This action affects only certain novel or unusual design features
on one model of airplane. It is not a rule of general applicability.
Under standard practice, the effective date of final special
conditions would be 30 days after the date of publication in the
Federal Register; however, as the certification date for the Boeing
Model 777-300ER airplane, as modified by Boeing, is imminent, the FAA
finds that good cause exists to make these special conditions effective
upon publication in the Federal Register.
[[Page 51086]]
List of Subjects in 14 CFR Part 25
Aircraft, Aviation safety, Reporting and recordkeeping
requirements.
The authority citation for these special conditions is as follows:
Authority: 49 U.S.C. 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 Boeing Model 777-300ER airplanes
modified by Boeing.
Oblique (Side-Facing) Seats Special Conditions
In addition to the requirements of Sec. 25.562:
1. Head Injury Criteria (HIC)
Compliance with Sec. 25.562(c)(5) is required, except that, if the
anthropomorphic test device (ATD) has no apparent contact with the seat
and related 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 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 which 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
a. 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.
b. 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
c. In addition, peak upper-neck Fz must be below 937 lb
in tension and 899 lb in compression.
d. Rotation of the head about its vertical axis relative to the
torso is limited to 105 degrees in either direction from forward-
facing.
e. 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-axis 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 in the
strike direction from the nominal seating position. Evaluation during
rebound need not 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.
Inflatable Lapbelt Special Conditions
The inflatable lapbelts must meet special conditions no. 25-187A-
SC, ``Boeing Model 777 Series Airplanes; Seats with Inflatable
Lapbelts.''
Note: As indicated in special conditions no. 25-187A-SC,
inflatable lapbelts must be shown to not affect emergency-egress
capabilities in the main aisle, cross-aisle, and passageway.
Issued in Renton, Washington, on July 8, 2016.
Michael Kaszycki,
Assistant Manager, Transport Airplane Directorate, Aircraft
Certification Service.
[FR Doc. 2016-18323 Filed 8-2-16; 8:45 am]
BILLING CODE 4910-13-P