[Federal Register Volume 72, Number 227 (Tuesday, November 27, 2007)]
[Proposed Rules]
[Pages 66085-66087]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-23079]


 ========================================================================
 Proposed Rules
                                                 Federal Register
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 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
 
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  Federal Register / Vol. 72, No. 227 / Tuesday, November 27, 2007 / 
Proposed Rules  

[[Page 66085]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM385; Notice No. 25-07-17-SC]


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

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed special conditions.

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SUMMARY: This action proposes special conditions 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 
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 December 12, 2007.

ADDRESSES: You must mail two copies of your comments to: Federal 
Aviation Administration, Transport Airplane Directorate, Attn: Rules 
Docket (ANM-113), Docket No. NM385, 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. NM385. 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: 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:

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 9 a.m. and 5 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 the FAA to acknowledge receipt of your comments on this 
proposal, 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 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 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,

[[Page 66086]]

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., 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.

Definition of ``Non-Traditional, Large, Non-Metallic Panel''

    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 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

[[Page 66087]]

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.

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.

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 Proposed Special Conditions

    Accordingly, the Federal Aviation Administration (FAA) proposes the 
following special conditions 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 Sec.  121.312, and
    c. Airplanes exempted from Sec.  25.853, Amendment 25-61 or later.

    Issued in Renton, Washington, on November 19, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E7-23079 Filed 11-26-07; 8:45 am]
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