[Federal Register Volume 76, Number 2 (Tuesday, January 4, 2011)]
[Proposed Rules]
[Pages 291-292]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-33221]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM439 Special Conditions No. 25-10-04-SC]


Special Conditions: Gulfstream Model GVI Airplane; Single-
Occupant Side-Facing Seats

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed special conditions.

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SUMMARY: This action proposes special conditions for the Gulfstream GVI 
airplane. This airplane will have a novel or unusual design feature(s) 
associated with single-occupant side-facing seats. 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: We must receive your comments by February 18, 2011.

ADDRESSES: You must mail two copies of your comments to: Federal 
Aviation Administration, Transport Airplane Directorate, Attn: Rules 
Docket (ANM-113), Docket No. NM439, 1601 Lind Avenue, SW., Renton, 
Washington 98057-3356. You may deliver two copies to the Transport 
Airplane Directorate at the above address. You must mark your comments: 
Docket No. NM439. You can inspect comments in the Rules Docket 
weekdays, except Federal holidays, between 7:30 a.m. and 4 p.m.

FOR FURTHER INFORMATION CONTACT: Daniel Jacquet, FAA, Airframe/Cabin 
Safety Branch, ANM-115, Transport Standards Staff, Transport Airplane 
Directorate, Aircraft Certification Service, 1601 Lind Avenue, SW., 
Renton, Washington 98057-3356; telephone (425) 227-2676; facsimile 
(425) 227-1320.

SUPPLEMENTARY INFORMATION:

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 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. You can inspect the docket 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 based on the comments we receive.
    If you want us to acknowledge receipt of your comments on this 
proposal, include with your comments a self-addressed, stamped postcard 
on which you have written the docket number. We will stamp the date on 
the postcard and mail it back to you.

Background

    On September 28, 2006, Gulfstream Aerospace Corporation (hereafter 
referred to as ``Gulfstream'') applied for an FAA type certificate for 
its new Gulfstream Model GVI passenger airplane. The Gulfstream Model 
GVI airplane will be an all-new, two-engine jet transport airplane with 
an executive cabin interior. The maximum takeoff weight will be 99,600 
pounds, with a maximum passenger count of 19 passengers.

Type Certification Basis

    Under provisions of Title 14, Code of Federal Regulations (14 CFR) 
21.17, Gulfstream must show that the Gulfstream Model GVI airplane 
(hereafter referred to as ``the GVI'') meets the applicable provisions 
of 14 CFR part 25, as amended by Amendments 25-1 through 25-119 and 25-
122. 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 GVI because of a novel or unusual 
design feature, special conditions are prescribed under the provisions 
of Sec.  21.16.
    In addition to complying with the applicable airworthiness 
regulations and special conditions, the GVI 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 must also issue a 
finding of regulatory adequacy pursuant to section 611 of Public Law 
92-574, the ``Noise Control Act of 1972.''
    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.  21.17(a)(2).
    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 features, the special conditions would also apply to the 
other model under provisions of Sec.  21.101.

Novel or Unusual Design Features

    The GVI offers interior arrangements, which include single-occupant 
side-facing seat installations. Dynamic testing of all seats approved 
for occupancy during takeoff and landing is required by Sec.  25.562. 
The pass/fail criteria for the testing developed in Amendment 25-64 to 
Sec.  25.562 focused primarily on fore/aft facing seats. Side-facing 
seat installations were not adequately addressed for transport category 
airplanes in this amendment.

Discussion of Proposed Special Conditions

    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.

[[Page 292]]

    Although Sec.  25.562 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 lumbar 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 
include 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 proposed 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.

Applicability

    As discussed above, this proposed special condition is applicable 
to the GVI. Should Gulfstream apply at a later date for a change to the 
type certificate to include another model incorporating the same novel 
or unusual design features, this proposed special condition would apply 
to that model as well.

Conclusion

    This action affects only certain novel or unusual design features 
of the GVI. It is not a rule of general applicability.

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 Proposed Special Conditions

    Accordingly, the Federal Aviation Administration (FAA) proposes the 
following special conditions as part of the type certification basis 
for the GVI airplanes.
    In addition to the airworthiness standards in Sec. Sec.  25.562 and 
25.785, the following proposed special conditions provide injury 
criteria and installation/testing guidelines that represent the minimum 
acceptable airworthiness standard for single-place side-facing seats:

A. The Proposed Injury Criteria

    1. 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.
    2. Body-to-Wall/Furnishing Contact: The seat must be installed 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.
    3. Thoracic Trauma: 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 (49 CFR) part 572, Subpart F, or its equivalent. 
TTI must be less than 85, as defined in 49 CFR part 572, subpart F. SID 
TTI data must be processed as defined in Federal Motor Vehicle Safety 
Standard (FMVSS) part 571.214, section S6.13.5.
    4. Pelvis: Pelvic lateral acceleration must be shown by dynamic 
test or by rational analysis based on previous test(s) of a similar 
seat installation not to exceed 130g. Pelvic acceleration data must be 
processed as defined in FMVSS part 571.214, section S6.13.5.
    5. 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.

B. General Test Guidelines

    1. One longitudinal test with the SID or its equivalent, undeformed 
floor, no yaw, and with all lateral structural supports (armrests/
walls).
    Pass/fail injury assessments: TTI and pelvic acceleration.
    2. One longitudinal test with the Hybrid II anthropomorphic test 
dummy (ATD), deformed floor, with 10 degrees yaw, and with all lateral 
structural support (armrests/walls).
    Pass/fail injury assessments: HIC; and upper torso restrain load, 
restraint system retention and pelvic acceleration.
    3. Vertical (14g) test is to be conducted with modified Hybrid II 
ATDs with existing pass/fail criteria.

    Issued in Renton, Washington, on December 22, 2010.
Jeffrey E. Duven,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2010-33221 Filed 1-3-11; 8:45 am]
BILLING CODE 4910-13-P