
[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


