```

[Federal Register Volume 82, Number 69 (Wednesday, April 12, 2017)]
[Rules and Regulations]
[Pages 17531-17533]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-07326]

=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2016-4158; Special Conditions No. 25-656-SC]

Special Conditions: Bombardier Inc. Model BD-700-2A12 and BD-700-
2A13 Airplanes; Fuselage In-Flight Fire Safety and Flammability 
Resistance of Aluminum-Lithium Material

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

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

SUMMARY: These special conditions are issued for the Bombardier Inc. 
(Bombardier) Model BD-700-2A12 and BD-700-2A13 airplanes. These 
airplanes will have a novel or unusual design feature when compared to 
the state of technology envisioned in the airworthiness standards for 
transport-category airplanes. This design feature is a fuselage 
fabricated using aluminum-lithium materials instead of conventional 
aluminum. The applicable airworthiness regulations do not contain 
adequate or appropriate fire-safety standards for this design feature. 
These special conditions contain the additional fire-safety standards 
that the Administrator considers necessary to establish a level of 
safety equivalent to that established by the existing airworthiness 
standards.

[[Page 17532]]

DATES: Effective May 12, 2017.

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 425-227-2195; facsimile 425-227-1320.

SUPPLEMENTARY INFORMATION: 

Background

    On May 30, 2012, Bombardier applied for an amendment to Type 
Certificate No. T00003NY to include the new Model BD-700-2A12 and BD-
700-2A13 airplanes. These airplanes are derivatives of the Model BD-700 
series of airplanes and are marketed as the Bombardier Global 7000 
(Model BD-700-2A12) and Global 8000 (Model BD-700-2A13). These 
airplanes are twin-engine, transport-category, executive-interior 
business jets. The maximum passenger capacity is 19 and the maximum 
takeoff weights are 106,250 lb. (Model BD-700-2A12) and 104,800 lb. 
(Model BD-700-2A13).

Type Certification Basis

    Under the provisions of Title 14, Code of Federal Regulations (14 
CFR) 21.101, Bombardier must show that the Model BD-700-2A12 and BD-
700-2A13 airplanes meet the applicable provisions of the regulations 
listed in Type Certificate No. T00003NY, or the applicable regulations 
in effect on the date of application for the change, except for earlier 
amendments as agreed upon by the FAA.
    In addition, the certification basis includes other regulations, 
special conditions, and exemptions that are not relevant to these 
special conditions. Type Certificate No. T00003NY will be updated to 
include a complete description of the certification basis for these 
airplane models.
    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 BD-700-2A12 and BD-700-2A13 
airplanes 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 novel or 
unusual design feature, or should any other model already included on 
the same type certificate be modified to incorporate the same novel or 
unusual design feature, these 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 BD-700-2A12 and BD-700-2A13 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 14 CFR 11.19, in 
accordance with Sec.  11.38, and they become part of the type-
certification basis under Sec.  21.101.

Novel or Unusual Design Feature

    Bombardier Model BD-700-2A12 and BD-700-2A13 airplanes will 
incorporate the following novel or unusual design feature: The fuselage 
will be fabricated using aluminum-lithium alloy materials instead of 
conventional aluminum.

Discussion

    The Bombardier Model BD-700-2A12 and BD-700-2A13 airplanes will be 
fabricated using aluminum-lithium materials. The performance of 
airplanes consisting of a conventional aluminum fuselage, in an in-
flight, inaccessible-fire scenario, is understood based on service 
history, and extensive intermediate- and large-scale fire testing. 
Experience has shown that eliminating fire propagation of the interior 
and insulation materials tends to increase survivability because other 
aspects of in-flight fire safety (e.g., toxic-gas emission and smoke 
obscuration) are typically byproducts of the propagating fire. The 
fuselage itself does not contribute to in-flight fire propagation. This 
may not be the case for a fuselage fabricated from aluminum-lithium 
materials. Therefore, special conditions are necessary so that the 
Model BD-700-2A12 and BD-700-2A13 airplanes provide protection against 
in-flight fires propagating along the surface of the fuselage.
    In the past, fatal in-flight fires have originated in inaccessible 
areas of airplanes where thermal or acoustic insulation was located 
adjacent to the airplane's aluminum fuselage skin. Research revealed 
that this area has been the path for flame propagation and fire growth. 
The FAA determined, in five incidents in the 1990s, that unexpected 
flame spread along thermal and acoustic insulation-film covering 
material, raising concerns about the fire performance of this 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, etc.).
    In 1996, the FAA Technical Center began a program to develop new 
fire-test criteria for insulation films directly relating to in-flight 
fire resistance. This development program resulted in a new test 
method--the radiant-panel test--and also resulted in test criteria 
specifically established for improving the in-flight fire ignition and 
flame propagation of thermal and acoustic insulation materials based on 
actual, on-board fire scenarios.
    The FAA determined that a test similar to the test for the 
measurement of insulation burnthrough resistance (14 CFR part 25, 
Appendix F, Part VII, ``Test Method to Determine the Burnthrough 
Resistance of Thermal/Acoustic Insulation Materials'') could be used to 
assess the flammability characteristics of the proposed fuselage 
aluminum-lithium material. The only change to the test is the size of 
the sample and the sample holder, to accommodate panels of the fuselage 
material.
    Bombardier must use the test method contained in Part VII of 
Appendix F, Test Method, for determining the burnthrough resistance of 
thermal-acoustic insulation materials, with the slight changes to the 
sample size and sample holder, as described in these special 
conditions, to show that the aluminum-lithium material complies with 
applicable requirements.
    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.

Discussion of Comments

    Notice of Proposed Special Conditions No. 25-16-06-SC for the 
Bombardier Model BD-700-2A12 and BD-700-2A11 airplanes was published in 
the Federal Register on October 26, 2016 (81 FR 74348). One comment was 
received.
    The commenter acknowledged that the use of the aluminum-lithium 
alloy would require full certification to the existing regulations. 
However, they contend that the material is not novel and unusual and 
does not require special conditions.
    The FAA does not agree. While it is true that, with materials 
presently tested, the proposed aluminum-lithium alloy does not appear 
to pose a significant risk, the existing regulations and guidance do 
not adequately address the use of this specific alloy technology.
    Therefore, special conditions are required until the regulations 
are amended to provide sufficient

[[Page 17533]]

requirements for the application of this new alloy technology.

Applicability

    As discussed above, these special conditions are applicable to 
Bombardier Model BD-700-2A12 and BD-700-2A13 airplanes. Should 
Bombardier apply at a later date for a change to the type certificate 
to include another model incorporating the same novel or unusual design 
feature, these special conditions would apply to the other model as 
well.

Conclusion

    This action affects only a certain novel or unusual design feature 
on Bombardier Model BD-700-2A12 and BD-700-2A13 airplanes. It is not a 
rule of general applicability and affects only the applicant who 
applied to FAA for approval of this feature on the airplane.

List of Subjects in 14 CFR Part 25

    Aircraft, Aviation safety, Reporting and recordkeeping 
requirements.

0
The authority citation for these special conditions is as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701, 44702, 44704.

The Special Conditions

0
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 Bombardier Model BD-700-2A12 and BD-
700-2A13 airplanes.
    1. Bombardier must demonstrate that the aluminum-lithium material 
has equal or better flammability-resistance characteristics than the 
aluminum-alloy sheet material typically used as skin material on 
similar airplanes.
    2. The test set-up and methodology must be in accordance with the 
tests described in 14 CFR part 25, Appendix F, Part VII, except for the 
following.
    a. Each test sample must consist of a flat test specimen. A set of 
three samples of aluminum-lithium sheet material must be tested. The 
size of each sample must be 16 inches wide by 24 inches long by 0.063 
inch thick.
    b. The test samples must be installed into a steel-sheet subframe 
with outside dimensions of 18 inches by 32 inches. The subframe must 
have a 14.5-inch by 22.5-inch opening cut into it. The tests samples 
must be mounted onto the subframe using 0.250-20 UNC threaded bolts.
    c. Test specimens must be conditioned at 70 [deg]F + 5 [deg]F, and 
55% + 5% humidity, for at least 24 hours before testing.
    3. The aluminum-lithium material must not ignite during any of the 
tests.

    Issued in Renton, Washington, on April 3, 2017.
Michael Kaszycki,
Assistant Manager, Transport Airplane Directorate, Aircraft 
Certification Service.
[FR Doc. 2017-07326 Filed 4-11-17; 8:45 am]
 BILLING CODE 4910-13-P
```