[Federal Register Volume 79, Number 26 (Friday, February 7, 2014)]
[Proposed Rules]
[Pages 7406-7408]
[FR Doc No: 2014-02618]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No.FAA-2014-0067; Notice No. 25-14-01-SC]

Special Conditions: Learjet Inc., Model LJ-200-1A10 Airplane;
Composite Fuselage In-Flight Fire/Flammability Resistance

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed special conditions.

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SUMMARY: This action proposes special conditions for the Learjet Inc.
Model LJ-200-1A10 airplane. This airplane will have a novel or unusual
design feature

when compared to the state of technology envisioned in the
airworthiness standards for transport category airplanes. The fuselage
of the LJ-200-1A10 will be made of composite materials rather than
conventional aluminum, which may affect fire propagation during an in-
flight fire. 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 March 24, 2014.

ADDRESSES: Send comments identified by docket number FAA-2014-0067
using any of the following methods:
     Federal eRegulations Portal: Go to http://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<PHONE_NUMBER>.
    Privacy: The FAA will post all comments it receives, without
change, to http://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 http://DocketsInfo.dot.gov/.
    Docket: Background documents or comments received may be read at
http://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: Alan Sinclair, FAA, Airframe and Cabin
Safety Branch, ANM-115, Transport Airplane Directorate, Aircraft
Certification Service, 1601 Lind Avenue SW., Renton, Washington, 98057-
3356; telephone<PHONE_NUMBER>; facsimile<PHONE_NUMBER>.

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 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 February 9, 2009, Learjet Inc. applied for a type certificate
for their new Model LJ-200-1A10 airplane (hereafter referred to as the
``Model LJ-200''). The Model LJ-200 is a business class airplane
powered by two high-bypass turbine engines with an estimated maximum
takeoff weight of 35,550 pounds and an interior configuration for up to
10 passengers.
    The Model LJ-200 is the first composite fuselage airplane design
manufactured by Learjet Inc. A fuselage manufactured from composite
material is considered a unique and novel design with respect to
existing regulations for this type of aircraft. The performance of
aircraft consisting of a conventional aluminum fuselage in an
inaccessible in-flight fire scenario is understood based on service
history and extensive intermediate and large-scale fire testing. The
fuselage itself does not contribute to in-flight fire propagation. This
may not be the case for an all composite fuselage. The existing
regulations do not adequately address protection against an in-flight
fire for an all composite fuselage. These proposed special conditions
are necessary to ensure a level of safety equivalent to that provided
by existing regulations.

Type Certification Basis

    Under the provisions of Title 14, Code of Federal Regulations (14
CFR) 21.17, Learjet Inc. must show that the Model LJ-200 airplane meets
the applicable provisions of part 25, as amended by Amendments 25-1
through 25-127, and 14 CFR part 26, as amended by Amendment 26-1
through 26-2.
    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 LJ-200 airplane because of a
novel or unusual design feature, special conditions are prescribed
under the provisions of 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 special conditions would also
apply to the other model under Sec.  21.101.
    In addition to the applicable airworthiness regulations and special
conditions, the Model LJ-200 airplane 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 Sec.  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).

Novel or Unusual Design Features

    The Model LJ-200 airplane will incorporate the following novel or
unusual design features: The fuselage will be fabricated using
composite materials instead of conventional aluminum.

Discussion

    The Model LJ-200 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 LJ-200 airplane 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 LJ-200 airplane is to conduct large-scale tests.
These large-scale tests would use a mock-up of a Model LJ-200 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, these special conditions or the method
of compliance would need to be modified in order to take the more
severe threat into account.
    Despite the major change from aluminum to composite material for
the fuselage, the Model LJ-200 must have in-flight fire survivability
such that the composite fuselage is no worse than that of a similar
aluminum structure.

Applicability

    As discussed above, these special conditions are applicable to the
Model LJ-200 airplane. Should Learjet Inc. 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.

Conclusion

    This action affects only certain novel or unusual design features
on one model of 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 Conditions

    Accordingly, the Federal Aviation Administration (FAA) proposes the
following special conditions as part of the type certification basis
for Learjet LJ-200-1A10 airplane.
    Composite Fuselage In-Flight Fire/Flammability Resistance. The
Learjet Model LJ-200 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 January 31, 2014.
John P. Piccola,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 2014-02618 Filed 2-6-14; 8:45 am]
BILLING CODE 4910-13-P