[Federal Register Volume 72, Number 248 (Friday, December 28, 2007)]
[Rules and Regulations]
[Pages 73585-73587]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-25077]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM385; Special Conditions No. 25-364-SC]


Special Conditions: Boeing Model 757 Series Airplanes; Seats With 
Non-Traditional, Large, Non-Metallic Panels

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

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SUMMARY: These special conditions are issued for Boeing Model 757 
Series Airplanes. These airplanes, as modified by Triad International 
Maintenance Company (TIMCO), will have a novel or unusual design 
feature(s) associated with seats that include non-traditional, large, 
non-metallic panels that would affect survivability during a post-crash 
fire event. 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: Effective Date: The effective date of these special conditions 
is December 18, 2007.

FOR FURTHER INFORMATION CONTACT: Dan Jacquet, FAA, Airframe/Cabin 
Safety Branch, ANM-115, Transport Airplane Directorate, Aircraft 
Certification Service, 1601 Lind Avenue, SW., Renton, Washington, 
98057-3356; telephone (425) 227-2676; facsimile (425) 227-1232; 
electronic mail [email protected].

SUPPLEMENTARY INFORMATION:

Future Requests for Installation of Seats with Non-Traditional, Large, 
Non-Metallic Panels

    We anticipate that seats with non-traditional, large, non-metallic 
panels will be installed in other makes and models of airplanes. We 
have made the determination to require special conditions for all 
applications requesting the installation of seats with non-traditional, 
large, non-metallic panels until the airworthiness requirements can be 
revised to address this issue. Having the same standards across the 
range of airplane makes and models will ensure a level playing field 
for the aviation industry.

Background

    On July 31, 2007, Triad International Maintenance Company (TIMCO), 
623 Radar Road, Greensboro, North Carolina 27410, applied for a 
supplemental type certificate for installing seats that include non-
traditional, large, non-metallic panels in a Boeing Model 757 series 
airplane. The Boeing Model 757 series airplanes, currently approved 
under Type Certificate No. A2NM, are swept-wing, conventional tail, 
twin-engine, turbofan-powered, single aisle, medium-sized transport 
category airplanes.
    The applicable regulations to airplanes currently approved under 
Type Certificate No. A2NM do not require seats to meet the more 
stringent flammability standards required of large, non-metallic panels 
in the cabin interior. At the time the applicable rules were written, 
seats were designed with a metal frame covered by fabric, not with 
large, non-metallic panels. Seats also met the then recently adopted 
standards for flammability of seat

[[Page 73586]]

cushions. With the seat design being mostly fabric and metal, the 
contribution to a fire in the cabin had been minimized and was not 
considered a threat. For these reasons, seats did not need to be tested 
to heat release and smoke emission requirements.
    Seat designs have now evolved to occasionally include non-
traditional, large, non-metallic panels. Taken in total, the surface 
area of these panels is on the same order as the sidewall and overhead 
stowage bin interior panels. To provide the level of passenger 
protection intended by the airworthiness standards, these non-
traditional, large, non-metallic panels in the cabin must meet the 
standards of Title 14 Code of Federal Regulations (CFR), part 25, 
Appendix F, parts IV and V, heat release and smoke emission 
requirements.

Type Certification Basis

    Under the provisions of 14 CFR 21.101, TIMCO must show that the 
Boeing Model 757 series airplanes, as changed, continue to meet the 
applicable provisions of the regulations incorporated by reference in 
Type Certificate No. A2NM, 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. A2NM are as follows:
     For Model 757-200 airplanes--part 25, as amended by 
Amendment 25-1 through Amendment 25-45. In addition, an equivalent 
safety finding exists with respect to Sec.  25.853(c), Compartment 
interiors.
     For Model 757-300 airplanes--part 25, as amended by 
Amendment 25-1 through Amendment 25-85 with the exception listed: 
Section 25.853(d)(3), Compartment interiors, at Amendment 25-72.
    In addition, the certification basis includes certain special 
conditions, exemptions, or later amended sections of the applicable 
part that are not relevant to these special conditions.
    If the Administrator finds that the applicable airworthiness 
regulations (i.e., part 25) do not contain adequate or appropriate 
safety standards for the Boeing Model 757 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 757 series airplanes 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 Sec.  11.19, under 
Sec.  11.38 and they become part of the type certification basis under 
Sec.  21.101.
    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 or similar novel or unusual design 
feature, the special conditions would also apply to the other model 
under Sec.  21.101.

Novel or Unusual Design Features

    The Boeing Model 757 series airplanes will incorporate the 
following novel or unusual design features: These models offer interior 
arrangements that include passenger seats that incorporate non-
traditional, large, non-metallic panels in lieu of the traditional 
metal frame covered by fabric. The flammability properties of these 
panels have been shown to significantly affect the survivability of the 
cabin in the case of fire. These seats are considered a novel design 
for transport category airplanes that include Amendment 25-61 and 
Amendment 25-66 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 seat designs that incorporate non-traditional, 
large, non-metallic panels in their designs. In order to provide a 
level of safety that is equivalent to that afforded to the balance of 
the cabin, additional airworthiness standards, in the form of special 
conditions, are necessary. These special conditions supplement Sec.  
25.853. The requirements contained in these special conditions consist 
of applying the identical test conditions required of all other large 
panels in the cabin, to seats with non-traditional, large, non-metallic 
panels.
    A non-traditional, large, non-metallic panel, in this case, is 
defined as a panel with exposed-surface areas greater than 1.5 square 
feet installed per seat place. The panel may consist of either a single 
component or multiple components in a concentrated area. Examples of 
parts of the seat where these non-traditional panels are installed 
include, but are not limited to: seat backs, bottoms and leg/foot 
rests, kick panels, back shells, credenzas and associated furniture. 
Examples of traditional exempted parts of the seat include: arm caps, 
armrest close-outs such as end bays and armrest-styled center consoles, 
food trays, video monitors, and shrouds.

Clarification of ``Exposed''

    ``Exposed'' is considered to include panels that are directly 
exposed to the passenger cabin in the traditional sense, and panels 
that are enveloped, such as by a dress cover. Traditional fabrics or 
leathers currently used on seats are excluded from these special 
conditions. These materials must still comply with Sec.  25.853(a) and 
Sec.  25.853(c) if used as a covering for a seat cushion, or Sec.  
25.853(a) if installed elsewhere on the seat. Non-traditional, large, 
non-metallic panels covered with traditional fabrics or leathers will 
be tested without their coverings or covering attachments.

Discussion

    In the early 1980s the FAA conducted extensive research on the 
effects of post-crash flammability in the passenger cabin. As a result 
of this research and service experience, we adopted new standards for 
interior surfaces associated with large surface area parts. 
Specifically, the rules require measurement of heat release and smoke 
emission (part 25, Appendix F, parts IV and V) for the affected parts. 
Heat release has been shown to have a direct correlation with post-
crash fire survival time. Materials that comply with the standards 
(i.e., Sec.  25.853 entitled ``Compartment interiors'' as amended by 
Amendment 25-61 and Amendment 25-66) extend survival time by 
approximately 2 minutes over materials that do not comply.
    At the time these standards were written the potential application 
of the requirements of heat release and smoke emission to seats was 
explored. The seat frame itself was not a concern because it was 
primarily made of aluminum and there were only small amounts of non-
metallic materials. It was determined that the overall effect on 
survivability was negligible, whether or not the food trays met the 
heat release and smoke requirements. The requirements therefore did not 
address seats. The preambles to both the Notice of Proposed Rule Making 
(NPRM), Notice No. 85-10 (50 FR 15038, April 16, 1985) and the Final 
Rule at Amendment 25-61 (51 FR 26206, July 21, 1986), specifically note 
that seats were excluded ``because the recently-adopted standards for 
flammability of seat cushions will greatly inhibit involvement of the 
seats.''
    Subsequently, the Final Rule at Amendment 25-83 (60 FR 6615, March 
6, 1995) clarified the definition of minimum panel size: ``It is not 
possible

[[Page 73587]]

to cite a specific size that will apply in all installations; however, 
as a general rule, components with exposed-surface areas of one square 
foot or less may be considered small enough that they do not have to 
meet the new standards. Components with exposed-surface areas greater 
than two square feet may be considered large enough that they do have 
to meet the new standards. Those with exposed-surface areas greater 
than one square foot, but less than two square feet, must be considered 
in conjunction with the areas of the cabin in which they are installed 
before a determination could be made.''
    In the late 1990s, the FAA issued Policy Memorandum 97-112-39, 
Guidance for Flammability Testing of Seat/Console Installations, 
October 17, 1997 (http://rgl.faa.gov). That memo was issued when it 
became clear that seat designs were evolving to include large, non-
metallic panels with surface areas that would impact survivability 
during a cabin fire event, comparable to partitions or galleys. The 
memo noted that large surface area panels must comply with heat release 
and smoke emission requirements, even if they were attached to a seat. 
If the FAA had not issued such policy, seat designs could have been 
viewed as a loophole to the airworthiness standards that would result 
in an unacceptable decrease in survivability during a cabin fire event.
    In October of 2004, an issue was raised regarding the appropriate 
flammability standards for passenger seats that incorporated non-
traditional, large, non-metallic panels in lieu of the traditional 
metal covered by fabric. The Seattle Aircraft Certification Office and 
Transport Standards Staff reviewed this design and determined that it 
represented the kind and quantity of material that should be required 
to pass the heat release and smoke emissions requirements. We have 
determined that special conditions would be promulgated to apply the 
standards defined in Sec.  25.853(d) to seats with large, non-metallic 
panels in their design.

Discussion of Comments

    Notice of proposed special conditions No. 25-07-17-SC, pertaining 
to Boeing Model 757 series airplanes, was published in the Federal 
Register on November 27, 2007. No comments were received and the 
special conditions are adopted as proposed.

Applicability

    As discussed above, these special conditions are applicable to 
Boeing Model 757 series airplanes. It is not our intent, however, to 
require seats with large, non-metallic panels to meet Sec.  25.853, 
Appendix F, parts IV and V, if they are installed in cabins of 
airplanes that otherwise are not required to meet these standards. 
Because the heat release and smoke testing requirements of Sec.  25.853 
per Appendix F, parts IV and V, are not part of the type certification 
basis of the Model 757, these special conditions are only applicable if 
the Model 757 series airplanes are in 14 CFR part 121 operations. 
Section 121.312 requires compliance with the heat release and smoke 
testing requirements of Sec.  25.853, for certain airplanes, 
irrespective of the type certification bases of those airplanes. For 
Model 757 series airplanes, these are the airplanes that would be 
affected by these special conditions. Should TIMCO apply at a later 
date for a supplemental type certificate to modify any other model 
included on Type Certificate No. A2NM to incorporate the same novel or 
unusual design feature, the special conditions would apply to that 
model as well.

Effective Upon Issuance

    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 delivery date for the Boeing Model 
757 series airplane modified by TIMCO is imminent, the FAA finds that 
good cause exists to make these special conditions effective upon 
issuance.

Conclusion

    This action affects only certain novel or unusual design features 
on one model series of airplanes. 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.

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 757 series airplanes 
modified by TIMCO.
    1. Except as provided in paragraph 3 of these special conditions, 
compliance with Title 14 CFR part 25, Appendix F, parts IV and V, heat 
release and smoke emission, is required for seats that incorporate non-
traditional, large, non-metallic panels that may either be a single 
component or multiple components in a concentrated area in their 
design.
    2. The applicant may designate up to and including 1.5 square feet 
of non-traditional, non-metallic panel material per seat place that 
does not have to comply with special condition Number 1, above. A 
triple seat assembly may have a total of 4.5 square feet excluded on 
any portion of the assembly (e.g., outboard seat place 1 square foot, 
middle 1 square foot, and inboard 2.5 square feet).
    3. Seats do not have to meet the test requirements of Title 14 CFR 
part 25, Appendix F, parts IV and V, when installed in compartments 
that are not otherwise required to meet these requirements. Examples 
include:
    a. Airplanes with passenger capacities of 19 or less,
    b. Airplanes that do not have Sec.  25.853, Amendment 25-61 or 
later, in their certification basis and do not need to comply with the 
requirements of 14 CFR 121.312, and
    c. Airplanes exempted from Sec.  25.853, Amendment 25-61 or later.

    Issued in Renton, Washington, on December 18, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E7-25077 Filed 12-27-07; 8:45 am]
BILLING CODE 4910-13-P