[Federal Register Volume 70, Number 162 (Tuesday, August 23, 2005)]
[Rules and Regulations]
[Pages 49153-49155]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-16745]



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  Federal Register / Vol. 70, No. 162 / Tuesday, August 23, 2005 / 
Rules and Regulations  

[[Page 49153]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM326; Special Conditions No. 25-295-SC]


Special Conditions: Boeing Model 777 Series Airplanes; Side-
Facing Single-Occupant Seats Equipped With Inflatable Lapbelts

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 Boeing Model 777 
series airplanes. This airplane will have a novel or unusual design 
feature associated with side-facing single-occupant seats equipped with 
inflatable lapbelts. The applicable airworthiness regulations do not 
contain adequate or appropriate safety standards for these design 
features. These special conditions contain the additional safety 
standards the Administrator considers necessary to establish a level of 
safety equivalent to that established by the existing airworthiness 
standards.

DATES: The effective date of these special conditions is August 9, 
2005. Send your comments on or before October 7, 2005.

ADDRESSES: Comments on these special conditions may be mailed in 
duplicate to: Federal Aviation Administration, Transport Airplane 
Directorate, Attn: Rules Docket (ANM-113), Docket No. NM326, 1601 Lind 
Avenue, SW., Renton, Washington 98055-4056; or delivered in duplicate 
to the Transport Airplane Directorate at the above address. Comments 
must be marked: Docket No. NM326. Comments may be inspected in the 
Rules Docket weekdays, except Federal holidays, between 7:30 a.m. and 4 
p.m.

FOR FURTHER INFORMATION CONTACT: Alan Sinclair, FAA, Airframe/Cabin 
Safety Branch, ANM-115, Transport Airplane Directorate, Aircraft 
Certification Service, 1601 Lind Avenue, SW., Renton, Washington 98055-
4056; telephone (425) 227-2195, facsimile (425) 227-1232.

SUPPLEMENTARY INFORMATION: The FAA has determined that notice and 
opportunity for prior public comment hereon are impracticable because 
these procedures would significantly delay issuance of the approval 
design and thus delivery of the affected aircraft. 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 issuance.

Comments Invited

    We invite interested persons to participate in this rulemaking by 
submitting 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 ask 
that you send us two copies of written comments.
    We will file in the docket all comments we receive, as well as a 
report summarizing each substantive public contact with FAA personnel 
concerning these special conditions. The docket is available for public 
inspection before and after the comment closing date. If you wish to 
review the docket in person, go to the address in the ADDRESSES section 
of this preamble between 7:30 a.m. and 4 p.m., Monday through Friday, 
except Federal holidays.
    We will consider all comments we receive on or before the closing 
date for comments. We will consider comments filed late if it is 
possible to do so without incurring expense or delay. We may change 
these special conditions in light of the comments we receive.
    If you want the FAA to acknowledge receipt of your comments on 
these special conditions, include with your comments a pre-addressed, 
stamped postcard on which the docket number appears. We will stamp the 
date on the postcard and mail it back to you.

Background

    On July 26, 2004, Boeing Commercial Airplanes, P.O. Box 3707, 
Seattle, Washington 98124, applied for a type certificate design change 
to install single-occupant side-facing seats equipped with inflatable 
lapbelts in Boeing Model 777 series airplanes. The Model 777 series 
airplane is a swept-wing, conventional-tail, twin-engine, turbofan-
powered transport category airplane.

Type Certification Basis

    Under the provisions of 14 CFR 21.101, Boeing Commercial Airplanes 
must show that the Model 777 series airplanes, as changed, continue to 
meet the applicable provisions of the regulations incorporated by 
reference in Type Certificate No. T00001SE or the applicable 
regulations in effect on the date of application for the change. The 
regulations incorporated by reference in the type certificate are 
commonly referred to as the ``original type certification basis.'' The 
regulations incorporated by reference in Type Certificate No. T00001SE 
are as follows: 14 CFR part 25, Amendments 25-1 through 25-82 for the 
Model 777-200 and Amendments 25-1 through 25-86 with exceptions for the 
Model 777-300. The U.S. type certification basis for the Model 777 is 
established in accordance with Sec. Sec.  21.29 and 21.17 and the type 
certification application date. The U.S. type certification basis is 
listed in Type Certificate Data Sheet No. T00001SE.
    If the Administrator finds that the applicable airworthiness 
regulations (i.e., part 25 as amended) do not contain adequate or 
appropriate safety standards for Boeing Model 777 series airplanes 
because of a novel or unusual design feature, special conditions are 
prescribed under the provisions of Sec.  21.16.
    In addition to the applicable airworthiness regulations and special 
conditions, the Boeing Model 777 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.
    Special conditions, as appropriate, are issued in accordance with 
14 CFR 11.19 after public notice, as required by Sec.  11.38, and 
become part of the type certification basis in accordance with Sec.  
21.101(b)(2).

[[Page 49154]]

    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, the special conditions would also apply to the 
other model under the provisions of Sec.  21.101(a)(1).

Novel or Unusual Design Features

    The Boeing Model 777 offers interior arrangements which include 
single-occupant side-facing seat installations. These arrangements 
include a unique ``pod'' style of side-facing seats that use inflatable 
lapbelts instead of standard belts for occupant restraint. Side-facing 
seats are considered a novel design for transport category airplanes 
that include Amendment 25-64 in the certification basis, and were not 
considered when those airworthiness standards were established.
    The existing regulations do not provide adequate or appropriate 
safety standards for occupants of side-facing seats. In order to 
provide a level of safety that is equivalent to that afforded occupants 
of forward- and aft-facing seats, additional airworthiness standards, 
in the form of special conditions, are necessary. These special 
conditions supplement part 25 and, more specifically, supplement 
Sec. Sec.  25.562 and 25.785. The requirements contained in these 
special conditions consist of both test conditions and injury pass/fail 
criteria.

Discussion

    Section 25.785(b), ``Seats, berths, safety belts, and harnesses,'' 
requires that ``each seat * * * at each station designated as 
occupiable during takeoff and landing must be designed so that a person 
making proper use of these facilities will not suffer serious injury in 
an emergency landing as a result of the inertia forces specified in 
Sec. Sec.  25.561 and 25.562.'' Additionally, Sec.  25.562, ``Emergency 
landing dynamic conditions,'' requires dynamic testing of all seats 
occupied during takeoff and landing. The relative forces and injury 
mechanisms affecting the occupants of side-facing seats during an 
emergency landing are different from those of standard forward- or aft-
facing seats, or seats equipped with conventional restraint systems.
    Side-facing Seats: Amendment 25-64, which adopted Sec.  25.562, 
enhances occupant protection during emergency landing conditions. 
Although the rule was written with forward- and aft-facing seats in 
mind, the orientation of the seat does not change the relevant test 
conditions, and the rule applies to all seats regardless of 
orientation.
    The dynamic test conditions included in Sec.  25.562 are directly 
applicable to side-facing seats. However, for injury pass/fail 
criteria, the orientation of the seat may be significant. For forward-, 
aft-, and side-facing seats the injury criteria are currently limited 
to head, spine, and femur loads. The head and lumbar loads are critical 
but the femur load is not critical. For a side-facing seat, additional 
injury parameters may be identified and evaluation of those parameters 
would be necessary to provide an acceptable level of safety.
    When evaluating side-facing seats the following should be taken 
into consideration:
    1. The isolation of one occupant from another. Occupants should not 
rely on impact with other occupants to provide energy absorption; body-
to-body impacts are unacceptable.
    2. The restraint system and the retention of occupants in the seat. 
Addressing this concern may necessitate providing a means of restraint 
for the lower limbs as well as the torso. Failure to limit the forward 
(in the airplane's coordinate system) travel of the lower limbs may 
cause the occupant to come out of the restraint system or produce 
severe injuries due to the resulting position of the restraint system 
and/or twisting (torsional load) of the lower lumber spinal column.
    3. The load limit in the torso in the lateral direction. Human 
tolerance for side-facing seats differs from that for forward- or aft-
facing seats.
    The automotive industry has developed test procedures and occupant 
injury criteria appropriate for side impact conditions. The criteria 
includes limiting lateral pelvic accelerations and using the ``Thoracic 
Trauma Index,'' which is defined in 49 CFR 571.214. Use of the Side 
Impact Dummy (SID) identified in 49 CFR part 572, subpart F, rather 
than the Hybrid II dummy identified in 49 CFR part 572, subpart B, is 
required to evaluate these parameters. The Hybrid II dummy is used in 
the current Sec.  25.562 test. Testing with a SID is the best means 
available to assess the injury potential of a sideward impact 
condition. Such an evaluation is considered necessary to provide an 
acceptable level of safety for side-facing seats.
    The side-facing seat special conditions have been determined to 
result in a level of safety equivalent to that provided by the injury 
pass/fail criteria in Sec.  25.562 for forward- or aft-facing seats.
    Inflatable Lapbelts: From the standpoint of a passenger safety 
system, the inflatable lapbelt is unique because it is both an active 
and entirely autonomous device. While the automotive industry has good 
experience with airbags, which are similar to inflatable lapbelts, the 
conditions of use and reliance on the inflatable lapbelt as the sole 
means of injury protection in an airplane are quite different. In 
automobile installations, the airbag is a supplemental system that 
works in conjunction with an upper torso restraint. In addition, an 
automobile crash is more definable and is typically shorter in 
duration, which can simplify the activation logic of the airbag. The 
airplane operating environment is also quite different from automobiles 
and includes the potential for greater wear and tear and unanticipated 
abuse conditions (due to galley loading, passenger baggage, etc.). 
Airplanes also operate where exposure to high intensity electromagnetic 
fields could affect the inflatable lapbelt activation system.
    The lapbelt special conditions can be characterized as addressing 
either the safety performance of the inflatable lapbelt activation 
system, or the system's integrity against inadvertent activation. 
Because a crash requiring the use of inflatable lapbelts is a 
relatively rare event, and the consequences of an inadvertent 
activation are potentially quite severe, these latter requirements are 
more rigorous from a design standpoint.

Applicability

    As discussed above, these special conditions are applicable to the 
Boeing Model 777. Should the Boeing Company apply at a later date for a 
change to the type certificate to include another model incorporating 
the same novel or unusual design feature, the special conditions would 
apply to that model as well under the provisions of Sec.  21.101.

Conclusion

    This action affects only certain novel or unusual design features 
on the Boeing Model 777 airplane. It is not a rule of general 
applicability, and it affects only the applicant who applied to the FAA 
for approval of these features on the airplane.
    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 series airplanes is imminent, the

[[Page 49155]]

FAA finds that good cause exists to make these special conditions 
effective upon issuance.

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 the Boeing Model 777 airplane.
    In addition to the airworthiness standards of Sec. Sec.  25.562 and 
25.785, the minimum acceptable standards for dynamic certification of 
Boeing Model 777 single-occupant side-facing seats are as follows:

Additional Injury Criteria

    (a) Existing Criteria: All injury protection criteria of Sec.  
25.562(c)(1) through (c)(6) apply to the occupant of a side-facing 
seat. Head Injury Criterion (HIC) assessments are only required for 
head contact with the seat and/or adjacent structures.
    (b) Body-to-Wall/Furnishing Contact: Under the load condition 
defined in Sec.  25.562(b)(2), the seat must be installed immediately 
aft of a structure such as an interior wall or furnishing that will 
support the pelvis, upper arm, chest, and head of an occupant seated 
next to the structure. A conservative representation of the structure 
and its stiffness must be included in the tests. It is recommended, but 
not required, that the contact surface of this structure be covered 
with at least two inches of energy absorbing protective padding (foam 
or equivalent), such as Ensolite.
    (c) Thoracic Trauma: Under the load condition defined in Sec.  
25.562(b)(2), Thoracic Trauma Index (TTI) injury criterion must be 
substantiated by dynamic test or by rational analysis based on previous 
test(s) of a similar seat installation. Testing must be conducted with 
a Side Impact Dummy (SID), as defined by Title 49 Code of Federal 
Regulations (CFR) part 572, Subpart F, or its equivalent. The TTI must 
be less than 85, as defined in 49 CFR part 572, Subpart F. The SID TTI 
data must be processed as defined in Federal Motor Vehicle Safety 
Standard (FMVSS) part 571.214, section S6.13.5.
    (d) Pelvis: Under the load condition defined in Sec.  25.562(b)(2), 
pelvic lateral acceleration must be shown by dynamic test or by 
rational analysis based on previous test(s) of a similar seat 
installation to not exceed 130g. Pelvic acceleration data must be 
processed as defined in FMVSS part 571.214, section S6.13.5.
    (e) Shoulder Strap Loads: Where upper torso straps (shoulder 
straps) are used for occupants, tension loads in individual straps must 
not exceed 1,750 pounds. If dual straps are used for restraining the 
upper torso, the total strap tension loads must not exceed 2,000 
pounds.
    (f) Neck Injury Criteria: The seating system must protect the 
occupant from experiencing serious neck injury.

Inflatable Lapbelt Conditions

    (a) If inflatable lapbelts are used as the means of occupant 
restraint on single place side-facing seats, the requirements of 
existing Special Conditions 25-04-03-SC (1-14), ``Boeing Model 777 
Series Airplanes; Seats with Inflatable Lapbelts'' are incorporated by 
reference except for special conditions 1 and 3, which are replaced by 
(b) and (c) below.
    (b) Seats With Inflatable Lapbelts. It must be shown that the 
inflatable lapbelt will deploy and provide protection under crash 
conditions where it is necessary to prevent serious head, neck, 
thoracic, and pelvic lateral acceleration injury from body-to-wall/
furnishing contact. The means of protection must take into 
consideration a range of stature from two-year-old child to ninety-
fifth percentile male. The inflatable lapbelt must provide a consistent 
approach to energy absorption throughout the range. In addition, the 
following situations must be considered:
    1. The seat occupant is holding an infant.
    2. The seat occupant is a child in a child restraint device.
    3. The seat occupant is a child not using a child restraint device.
    4. The seat occupant is a pregnant woman.
    (c) The design must prevent the inflatable lapbelt from being 
either incorrectly buckled or incorrectly installed such that the 
inflatable lapbelt would not properly deploy. Alternatively, it must be 
shown that such deployment is not hazardous to the occupant, and will 
provide the required injury protection.


    Note: The existing means of controlling HIC, TTI and pelvic 
lateral acceleration result in a progressive reduction of injury 
severity for impact conditions less than the maximum specified by 
the requirements. However, airbag technology involves a step change 
in protection for impacts below and above that at which the airbag 
deploys. This could result in one or more of the injury criteria 
being higher at an intermediate impact condition than that resulting 
from the maximum. The step change in injury protection is 
acceptable, provided that the injury criteria values for any 
intermediate impact (whether or not the inflatable lapbelt delays) 
do not exceed the maximum allowed by the requirements.

Additional Test Requirements

    (a) One longitudinal test with the SID Anthropomorphic Test Dummy 
(ATD), undeformed floor, no yaw, and with all lateral structural 
supports (armrests/walls).
    Pass/fail injury assessments: The TTI and pelvic acceleration.
    (b) One longitudinal test with the Hybrid II ATD, deformed floor, 
with 10 degrees yaw, and with all lateral structural supports 
(armrests/walls).
    Pass/fail injury assessments: The HIC; upper torso restraint load, 
restraint system retention, and pelvic acceleration.
    (c) Vertical (14 G's) test is to be conducted with modified Hybrid 
II ATDs with existing pass/fail criteria.

    Note: It must be demonstrated that seats installed on plinths or 
pallets meet all applicable requirements. Compliance with the 
guidance contained in FAA Policy Memorandum PS-ANM-100-2000-00123, 
dated February 2, 2000, titled ``Guidance for Demonstrating 
Compliance with Seat Dynamic Testing for Plinths and Pallets'' will 
be acceptable to the FAA.


    Issued in Renton, Washington, on August 9, 2005.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 05-16745 Filed 8-22-05; 8:45 am]
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