Special Conditions: Airbus, Model A350-900 Series Airplane; Composite Fuselage In-Flight Fire/Flammability Resistance, 68775-68777 [2013-27413]

Download as PDF Federal Register / Vol. 78, No. 221 / Friday, November 15, 2013 / Proposed Rules September 20, 2011), submitted by the Natural Resources Defense Council (NRDC). The NRDC requested that the NRC conduct a rulemaking to address training and exercise requirements for severe accident mitigation guidelines and extensive damage mitigation guidelines. The NRC determined that the issues raised in PRM–50–102 are appropriate for consideration and will be considered in this Onsite Emergency Response Capabilities rulemaking. For the Nuclear Regulatory Commission. Shana Helton, Acting Deputy Director, Division of Policy and Rulemaking, Office of Nuclear Reactor Regulation . [FR Doc. 2013–27449 Filed 11–14–13; 8:45 am] BILLING CODE 7590–01–P DEPARTMENT OF TRANSPORTATION Federal Aviation Administration IV. Publicly Available Documents 14 CFR Part 25 By making documents publicly available, the NRC seeks to inform stakeholders of the current status of the NRC’s rulemaking development activities and to provide preparatory material for future public meetings. The NRC is not instituting a public comment period on these materials, but the public is encouraged to participate in related public meetings. In addition, the public will be given opportunity to provide comments on the proposed rule upon its publication in the Federal Register. The NRC may post additional materials, including other preliminary rule language, to the Federal rulemaking Web site at https://www.regulations.gov, under Docket ID NRC–2012–0031. The Federal rulemaking Web site allows you to receive alerts when changes or additions occur in a docket folder. To subscribe: (1) Navigate to the docket folder (NRC–2012–0031); (2) click the ‘‘Email Alert’’ link; and (3) enter your email address and select how frequently you would like to receive emails (daily, weekly, or monthly). [Docket No. FAA–2013–0898; Notice No. 25– 13–33–SC] emcdonald on DSK67QTVN1PROD with PROPOSALS V. Plain Writing The Plain Writing Act of 2010 (Pub. L. 111–274) requires Federal agencies to write documents in a clear, concise, well-organized manner that also follows other best practices appropriate to the subject or field and the intended audience. Although regulations are exempt under the Act, the NRC is applying the same principles to its rulemaking documents. Therefore, the NRC has written this document, including the preliminary proposed rule language, to be consistent with the Plain Writing Act. There will be an opportunity for public comment on the use of plain language when the proposed rule is published in the Federal Register. Dated at Rockville, Maryland, this 7th day of November, 2013. VerDate Mar<15>2010 16:36 Nov 14, 2013 Jkt 232001 Special Conditions: Airbus, Model A350–900 Series Airplane; Composite Fuselage In-Flight Fire/Flammability Resistance Federal Aviation Administration (FAA), DOT. ACTION: Notice of proposed special conditions. AGENCY: This action proposes special conditions for the Airbus Model A350– 900 series airplanes. This airplane will have a novel or unusual design features associated with the in-flight fire and flammability resistance of the composite fuselage. Experience has shown that eliminating fire propagation on the surface of interior and insulating materials enhances survivability since the threats from an in-flight fire (e.g., toxic gas emission and smoke obscuration) are typically by-products of a propagating fire. The Airbus Model A350–900 series airplanes must provide protection against an in-flight fire propagating along the surface of the fuselage. Special conditions are needed to address this design feature. 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: Send your comments on or before December 30, 2013. ADDRESSES: Send comments identified by docket number FAA–2013–0898 using any of the following methods: • Federal eRegulations Portal: Go to https://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 SUMMARY: PO 00000 Frm 00002 Fmt 4702 Sfmt 4702 68775 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 https://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 https://DocketsInfo.dot .gov/. Docket: Background documents or comments received may be read at https://www.regulations.gov/at any time. Follow the online instructions for accessing the docket or go to the 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: Jeff Gardlin, FAA, Airframe/Cabin Safety, ANM–115, Transport Airplane Directorate, Aircraft Certification Service, 1601 Lind Avenue SW., Renton, Washington, 98057–3356; telephone (425) 227–2136; 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 proposed special conditions, explain the reason for any recommended change, and include supporting data. We will consider all comments we receive on or before the closing date for comments. We may change these special conditions based on the comments we receive. Background On August 25, 2008, Airbus applied for a type certificate for their new Model A350–900 series airplane. Later, Airbus requested and the FAA approved an E:\FR\FM\15NOP1.SGM 15NOP1 emcdonald on DSK67QTVN1PROD with PROPOSALS 68776 Federal Register / Vol. 78, No. 221 / Friday, November 15, 2013 / Proposed Rules extension to the application for FAA type certification to June 28, 2009, The Model A350–900 series has a conventional layout with twin wingmounted Rolls Royce Trent engines. It features a twin aisle 9-abreast economy class layout, and accommodates side-byside placement of LD–3 containers in the cargo compartment. The basic Model A350–900 series configuration will accommodate 315 passengers in a standard two-class arrangement. The design cruise speed is Mach 0.85 with a Maximum Take-Off Weight of 602,000 lbs. Airbus proposes the Model A350– 900 series to be certified for extended operations (ETOPS) beyond 180 minutes at entry into service for up to a 420minute maximum diversion time. Experience has shown that eliminating fire propagation on the surface of interior and insulating materials enhances survivability since the threats from an in-flight fire (e.g., toxic gas emission and smoke obscuration) are typically by-products of a propagating fire. The Airbus Model A350–900 series airplane must provide protection against an in-flight fire propagating along the surface of the fuselage. In the past, fatal in-flight fires have originated in inaccessible areas of the aircraft where the thermal/acoustic insulation located adjacent to the aluminium aircraft skin has been the path for flame propagation and fire growth. Concern over the fire performance of thermal/acoustic insulation was initially raised by five incidents in the 1990’s which revealed unexpected flame spread along the insulation film covering material. In all cases, the ignition source was relatively modest and, in most cases, was electrical in origin (e.g., electrical short circuit, arcing caused by chafed wiring, ruptured ballast case). From 1972 until 2003 these materials were required to comply with a basic ‘‘Bunsen burner’’ requirement per Title 14 Code of Federal Regulations (14 CFR) 25.853(a), 25.855(d), and part 25, Appendix F, part I, paragraph (a)(1)(ii). These requirements prescribed that insulation materials must be self-extinguishing after having been subjected to the flame of a Bunsen burner for 12 seconds, in accordance with the procedures defined in part 25, Appendix F, part I, paragraph (b)(4). The average burn was not to exceed eight inches and the average flame time after removal of the flame source was not to exceed 15 seconds. Drippings from the test specimen were not to continue to flame for more than an average of five seconds after falling. Further concern with the flammability of thermal/acoustic insulation was VerDate Mar<15>2010 16:36 Nov 14, 2013 Jkt 232001 raised by the Transportation Safety Board (TSB) of Canada during their investigation of the fatal Swiss Air MD– 11 in-flight fire accident that occurred in September 1998 and involved 229 fatalities. TSB investigators reported that the fatal fire appeared to have been confined to the area above the cockpit and forward cabin ceiling and involved the insulation blankets. On August 21, 2001, the TSB recommended that flammability standards for interior materials should be based on realistic ignition scenarios and prevent the use of materials that sustain or propagate a fire. In 1996, the FAA Technical Center began a program to develop new fire test criteria for insulation films directly relating to the resistance of in-flight fire propagation. The current test standard was evaluated as well as another smallscale test method that has been used by airplane manufacturers to evaluate flame propagation on thermal/acoustic insulation materials. An inter-laboratory comparison of these methods revealed a number of deficiencies. Other smallscale tests developed by the FAA Technical Center did demonstrate that some insulation films would ignite and propagate flame in a confined space. As a result, a series of large-scale fire tests were conducted in a mock-up of the attic area above the passenger cabin ceiling. In a confined space, ignition and flame propagation may occur because of more extensive radiating heat and the trapping of melted film/scrim. Temperature (heat release) data was recorded and the degree of flame propagation was observed from the large-scale tests. A radiant panel test standard for flooring materials was a test method that provided good correlation to the large-scale model. The test method involved subjecting a material to a pilot flame while the material is heated by a radiant panel. The previously described development program resulted in a new test method (radiant panel test) and test criteria specifically established for improving the in-flight fire ignition/ flame propagation of thermal/acoustic insulation materials. A new part 25 airworthiness standard, § 25.856, became effective in September 2003, Amendment 25–111, requiring that all thermal/acoustic insulation materials installed in the fuselage must comply to this flammability and flame propagation requirement. The proposed standards are intended to ‘‘reduce the incidence and severity of cabin fires, particularly those ignited in inaccessible areas where thermal acoustic insulation materials are typically installed.’’ PO 00000 Frm 00003 Fmt 4702 Sfmt 4702 Type Certification Basis Under Title 14, Code of Federal Regulations (14 CFR) 21.17, Airbus must show that the Model A350–900 series airplane meets the applicable provisions of 14 CFR part 25, as amended by Amendments 25–1 through 25–128. 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 Model A350–900 series because of a novel or unusual design feature, special conditions are prescribed under § 21.16. 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 or similar novel or unusual design feature, the proposed special conditions would also apply to the other model under § 21.101. In addition to the applicable airworthiness regulations and proposed special conditions, the Model A350–900 series 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 and the FAA must issue a finding of regulatory adequacy under 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, under § 11.38, and they become part of the typecertification basis under § 21.17(a)(2). Novel or Unusual Design Features The Airbus Model A350–900 series airplane will incorporate the following novel or unusual design features: fuselage fabricated with composite materials. Discussion The Airbus Model A350–900 series airplane will make extensive use of composite materials in the fabrication of the majority of the wing, fuselage skin, stringers, spars, and most other structural elements of all major subassemblies of the airplane. Despite the major change from aluminum to composite material for the fuselage, the Model A350–900 series must have inflight survivability such that the composite fuselage does not propagate a fire. A methodology for assessing the inflight fire survivability of an allcomposite fuselage is therefore needed. The FAA believes that one way to assess the survivability within the cabin of the Model A350–900 series airplane is to conduct large-scale tests. This large-scale test would utilize a mock-up E:\FR\FM\15NOP1.SGM 15NOP1 Federal Register / Vol. 78, No. 221 / Friday, November 15, 2013 / Proposed Rules of an Airbus Model A350–900 series airplane fuselage skin/structure section of sufficient size to assess any tendency for fire propagation. The fire threat used to represent the realistic ignition source in the airplane would consist of a 4″ x 4″ x 9″ polyurethane foam block and 10 ml of Heptane. This ignition source provides approximately three minutes of flame time and would be positioned at various points and orientations within the mocked up installation to impinge on those areas of the fuselage considered to be most crucial. This fire threat was established based on an assessment of a range of potential ignition sources, coupled with possible contamination of materials. The FAA considers this a severe fire threat, encompassing a variety of scenarios. However, should ignition or fire sources of a greater severity be identified, the special condition or its method of compliance would need to be modified in order to take the more severe threat into account. Applicability As discussed above, these proposed special conditions apply to Airbus Model A350–900 series airplanes. Should Airbus apply later for a change to the type certificate to include another model incorporating the same novel or unusual design feature, the proposed special conditions would apply to that model as well. Conclusion This action affects only certain novel or unusual design features on the Airbus Model A350–900 series airplanes. 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. emcdonald on DSK67QTVN1PROD with PROPOSALS The Proposed Special Condition Accordingly, the Federal Aviation Administration (FAA) proposes the following special condition as part of the type certification basis for Airbus Model A350–900 series airplanes. Composite Fuselage In-Flight Fire/ Flammability Resistance In addition to the requirements of § 25.853(a) governing material flammability, the following special condition applies: The Airbus Model A350 composite fuselage structure must be shown to be resistant to flame propagation under the fire threat used to develop § 25.856(a). If VerDate Mar<15>2010 16:36 Nov 14, 2013 Jkt 232001 products of combustion are observed beyond the test heat source, they must be evaluated and found acceptable. Issued in Renton, Washington, on November 12, 2013. Jeffrey E. Duven, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 2013–27413 Filed 11–14–13; 8:45 am] BILLING CODE 4910–13–P DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 71 [Docket No. FAA–2013–0891; Airspace Docket No. 12–ASO–37] RIN 2120–AA66 Proposed Establishment of Area Navigation (RNAV) Routes; Atlanta, GA Federal Aviation Administration (FAA), DOT. ACTION: Notice of proposed rulemaking (NPRM). AGENCY: This action proposes to establish nine low-altitude RNAV routes (T-routes) in the Atlanta, GA area. The new routes would support the Atlanta Optimization of Airspace and Procedures in a Metroplex (OAPM) project. The proposed routes would have connectivity to the current airway structure and would provide routing through, around and over the busy Atlanta Metroplex airspace. DATES: Comments must be received on or before December 30, 2013. ADDRESSES: Send comments on this proposal to the U.S. Department of Transportation, Docket Operations, M– 30, 1200 New Jersey Avenue SE., West Building Ground Floor, Room W12–140, Washington, DC 20590–0001; telephone: (202) 366–9826. You must identify FAA Docket No. FAA–2013–0891 and Airspace Docket No. 12–ASO–37 at the beginning of your comments. You may also submit comments through the Internet at https://www.regulations .gov. FOR FURTHER INFORMATION CONTACT: Paul Gallant, Airspace Policy and ATC Procedures Group, Office of Airspace Services, Federal Aviation Administration, 800 Independence Avenue SW., Washington, DC 20591; telephone: (202) 267–8783. SUPPLEMENTARY INFORMATION: SUMMARY: Comments Invited Interested parties are invited to participate in this proposed rulemaking PO 00000 Frm 00004 Fmt 4702 Sfmt 4702 68777 by submitting such written data, views, or arguments as they may desire. Comments that provide the factual basis supporting the views and suggestions presented are particularly helpful in developing reasoned regulatory decisions on the proposal. Comments are specifically invited on the overall regulatory, aeronautical, economic, environmental, and energy-related aspects of the proposal. Communications should identify both docket numbers (FAA Docket No. FAA– 2013–0891 and Airspace Docket No. 12– ASO–37) and be submitted in triplicate to the Docket Management Facility (see ADDRESSES section for address and phone number). You may also submit comments through the Internet at https:// www.regulations.gov. Commenters wishing the FAA to acknowledge receipt of their comments on this action must submit with those comments a self-addressed, stamped postcard on which the following statement is made: ‘‘Comments to FAA Docket No. FAA–2013–0891 and Airspace Docket No. 12–ASO–37.’’ The postcard will be date/time stamped and returned to the commenter. All communications received on or before the specified closing date for comments will be considered before taking action on the proposed rule. The proposal contained in this action may be changed in light of comments received. All comments submitted will be available for examination in the public docket both before and after the closing date for comments. A report summarizing each substantive public contact with FAA personnel concerned with this rulemaking will be filed in the docket. Availability of NPRMs An electronic copy of this document may be downloaded through the Internet at https://www.regulations.gov. You may review the public docket containing the proposal, any comments received and any final disposition in person in the Dockets Office (see ADDRESSES section for address and phone number) between 9:00 a.m. and 5:00 p.m., Monday through Friday, except Federal holidays. An informal docket may also be examined during normal business hours at the office of the Eastern Service Center, Federal Aviation Administration, Room 210, 1701 Columbia Ave., College Park, GA 30337. Persons interested in being placed on a mailing list for future NPRM’s should contact the FAA’s Office of Rulemaking, (202) 267–9677, for a copy of Advisory Circular No. 11–2A, Notice of Proposed E:\FR\FM\15NOP1.SGM 15NOP1

Agencies

[Federal Register Volume 78, Number 221 (Friday, November 15, 2013)]
[Proposed Rules]
[Pages 68775-68777]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2013-27413]

=======================================================================
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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2013-0898; Notice No. 25-13-33-SC]

Special Conditions: Airbus, Model A350-900 Series Airplane;
Composite Fuselage In-Flight Fire/Flammability Resistance

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed special conditions.

-----------------------------------------------------------------------

SUMMARY: This action proposes special conditions for the Airbus Model
A350-900 series airplanes. This airplane will have a novel or unusual
design features associated with the in-flight fire and flammability
resistance of the composite fuselage. Experience has shown that
eliminating fire propagation on the surface of interior and insulating
materials enhances survivability since the threats from an in-flight
fire (e.g., toxic gas emission and smoke obscuration) are typically by-
products of a propagating fire. The Airbus Model A350-900 series
airplanes must provide protection against an in-flight fire propagating
along the surface of the fuselage. Special conditions are needed to
address this design feature. 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: Send your comments on or before December 30, 2013.

ADDRESSES: Send comments identified by docket number FAA-2013-0898
using any of the following methods:
Federal eRegulations Portal: Go to https://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 https://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 https://DocketsInfo.dot.gov/.
Docket: Background documents or comments received may be read at
https://www.regulations.gov/at any time. Follow the online instructions
for accessing the docket or go to the 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: Jeff Gardlin, FAA, Airframe/Cabin
Safety, ANM-115, Transport Airplane Directorate, Aircraft Certification
Service, 1601 Lind Avenue SW., Renton, Washington, 98057-3356;
telephone (425) 227-2136; 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 proposed special conditions,
explain the reason for any recommended change, and include supporting
data.
We will consider all comments we receive on or before the closing
date for comments. We may change these special conditions based on the
comments we receive.

Background

On August 25, 2008, Airbus applied for a type certificate for their
new Model A350-900 series airplane. Later, Airbus requested and the FAA
approved an

[[Page 68776]]

extension to the application for FAA type certification to June 28,
2009, The Model A350-900 series has a conventional layout with twin
wing-mounted Rolls Royce Trent engines. It features a twin aisle 9-
abreast economy class layout, and accommodates side-by-side placement
of LD-3 containers in the cargo compartment. The basic Model A350-900
series configuration will accommodate 315 passengers in a standard two-
class arrangement. The design cruise speed is Mach 0.85 with a Maximum
Take-Off Weight of 602,000 lbs. Airbus proposes the Model A350-900
series to be certified for extended operations (ETOPS) beyond 180
minutes at entry into service for up to a 420-minute maximum diversion
time.
Experience has shown that eliminating fire propagation on the
surface of interior and insulating materials enhances survivability
since the threats from an in-flight fire (e.g., toxic gas emission and
smoke obscuration) are typically by-products of a propagating fire. The
Airbus Model A350-900 series airplane must provide protection against
an in-flight fire propagating along the surface of the fuselage.
In the past, fatal in-flight fires have originated in inaccessible
areas of the aircraft where the thermal/acoustic insulation located
adjacent to the aluminium aircraft skin has been the path for flame
propagation and fire growth. Concern over the fire performance of
thermal/acoustic insulation was initially raised by five incidents in
the 1990's which revealed unexpected flame spread along the insulation
film covering material. In all cases, the ignition source was
relatively modest and, in most cases, was electrical in origin (e.g.,
electrical short circuit, arcing caused by chafed wiring, ruptured
ballast case). From 1972 until 2003 these materials were required to
comply with a basic ``Bunsen burner'' requirement per Title 14 Code of
Federal Regulations (14 CFR) 25.853(a), 25.855(d), and part 25,
Appendix F, part I, paragraph (a)(1)(ii). These requirements prescribed
that insulation materials must be self-extinguishing after having been
subjected to the flame of a Bunsen burner for 12 seconds, in accordance
with the procedures defined in part 25, Appendix F, part I, paragraph
(b)(4). The average burn was not to exceed eight inches and the average
flame time after removal of the flame source was not to exceed 15
seconds. Drippings from the test specimen were not to continue to flame
for more than an average of five seconds after falling.
Further concern with the flammability of thermal/acoustic
insulation was raised by the Transportation Safety Board (TSB) of
Canada during their investigation of the fatal Swiss Air MD-11 in-
flight fire accident that occurred in September 1998 and involved 229
fatalities. TSB investigators reported that the fatal fire appeared to
have been confined to the area above the cockpit and forward cabin
ceiling and involved the insulation blankets. On August 21, 2001, the
TSB recommended that flammability standards for interior materials
should be based on realistic ignition scenarios and prevent the use of
materials that sustain or propagate a fire.
In 1996, the FAA Technical Center began a program to develop new
fire test criteria for insulation films directly relating to the
resistance of in-flight fire propagation. The current test standard was
evaluated as well as another small-scale test method that has been used
by airplane manufacturers to evaluate flame propagation on thermal/
acoustic insulation materials. An inter-laboratory comparison of these
methods revealed a number of deficiencies. Other small-scale tests
developed by the FAA Technical Center did demonstrate that some
insulation films would ignite and propagate flame in a confined space.
As a result, a series of large-scale fire tests were conducted in a
mock-up of the attic area above the passenger cabin ceiling. In a
confined space, ignition and flame propagation may occur because of
more extensive radiating heat and the trapping of melted film/scrim.
Temperature (heat release) data was recorded and the degree of flame
propagation was observed from the large-scale tests. A radiant panel
test standard for flooring materials was a test method that provided
good correlation to the large-scale model. The test method involved
subjecting a material to a pilot flame while the material is heated by
a radiant panel.
The previously described development program resulted in a new test
method (radiant panel test) and test criteria specifically established
for improving the in-flight fire ignition/flame propagation of thermal/
acoustic insulation materials. A new part 25 airworthiness standard,
Sec. 25.856, became effective in September 2003, Amendment 25-111,
requiring that all thermal/acoustic insulation materials installed in
the fuselage must comply to this flammability and flame propagation
requirement. The proposed standards are intended to ``reduce the
incidence and severity of cabin fires, particularly those ignited in
inaccessible areas where thermal acoustic insulation materials are
typically installed.''

Type Certification Basis

Under Title 14, Code of Federal Regulations (14 CFR) 21.17, Airbus
must show that the Model A350-900 series airplane meets the applicable
provisions of 14 CFR part 25, as amended by Amendments 25-1 through 25-
128.
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 Model A350-900 series because of a
novel or unusual design feature, special conditions are prescribed
under Sec. 21.16.
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 or similar
novel or unusual design feature, the proposed special conditions would
also apply to the other model under Sec. 21.101.
In addition to the applicable airworthiness regulations and
proposed special conditions, the Model A350-900 series 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 and the FAA must
issue a finding of regulatory adequacy under 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,
under Sec. 11.38, and they become part of the type-certification basis
under Sec. 21.17(a)(2).

Novel or Unusual Design Features

The Airbus Model A350-900 series airplane will incorporate the
following novel or unusual design features: fuselage fabricated with
composite materials.

Discussion

The Airbus Model A350-900 series airplane will make extensive use
of composite materials in the fabrication of the majority of the wing,
fuselage skin, stringers, spars, and most other structural elements of
all major sub-assemblies of the airplane. Despite the major change from
aluminum to composite material for the fuselage, the Model A350-900
series must have in-flight survivability such that the composite
fuselage does not propagate a fire. A methodology for assessing the in-
flight fire survivability of an all-composite fuselage is therefore
needed.
The FAA believes that one way to assess the survivability within
the cabin of the Model A350-900 series airplane is to conduct large-
scale tests. This large-scale test would utilize a mock-up

[[Page 68777]]

of an Airbus Model A350-900 series airplane fuselage skin/structure
section of sufficient size to assess any tendency for fire propagation.
The fire threat used to represent the realistic ignition source in the
airplane would consist of a 4'' x 4'' x 9'' polyurethane foam block and
10 ml of Heptane. This ignition source provides approximately three
minutes of flame time and would be positioned at various points and
orientations within the mocked up installation to impinge on those
areas of the fuselage considered to be most crucial.
This fire threat was established based on an assessment of a range
of potential ignition sources, coupled with possible contamination of
materials. The FAA considers this a severe fire threat, encompassing a
variety of scenarios. However, should ignition or fire sources of a
greater severity be identified, the special condition or its method of
compliance would need to be modified in order to take the more severe
threat into account.

Applicability

As discussed above, these proposed special conditions apply to
Airbus Model A350-900 series airplanes. Should Airbus apply later for a
change to the type certificate to include another model incorporating
the same novel or unusual design feature, the proposed special
conditions would apply to that model as well.

Conclusion

This action affects only certain novel or unusual design features
on the Airbus Model A350-900 series airplanes. 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 Condition

Accordingly, the Federal Aviation Administration (FAA) proposes the
following special condition as part of the type certification basis for
Airbus Model A350-900 series airplanes.

Composite Fuselage In-Flight Fire/Flammability Resistance

In addition to the requirements of Sec. 25.853(a) governing
material flammability, the following special condition applies:
The Airbus Model A350 composite fuselage structure must be shown to
be resistant to flame propagation under the fire threat used to develop
Sec. 25.856(a). If products of combustion are observed beyond the test
heat source, they must be evaluated and found acceptable.

Issued in Renton, Washington, on November 12, 2013.
Jeffrey E. Duven,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 2013-27413 Filed 11-14-13; 8:45 am]
BILLING CODE 4910-13-P

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