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[Federal Register Volume 78, Number 211 (Thursday, October 31, 2013)]
[Proposed Rules]
[Pages 65231-65233]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2013-25663]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2013-0819; Notice No. 25-13-06-SC]

Special Conditions: Bombardier Inc., Models BD-500-1A10 and BD-
500-1A11 series airplanes; Fuselage In-Flight Fire Safety and 
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 Bombardier 
Inc. Model BD-500-1A10 and BD-500-1A11 series airplanes. These 
airplanes will have a novel or unusual design feature associated with 
the materials used to fabricate the fuselage, 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 December 16, 2013.

ADDRESSES: Send comments identified by docket number [FAA-2013-0819] 
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 8 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 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 425-227-2195; facsimile 425-227-1232.

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 December 10, 2009, Bombardier Inc. applied for a type 
certificate for their new Model BD-500-1A10 and BD-500-1A11 series 
airplanes. The Model BD-500-1A10 and BD-500-1A11 series airplanes are 
swept-wing monoplanes with pressurized cabins, and they share an 
identical supplier base and significant common design elements. The 
fuselages are aluminum alloy material, blended double-bubble design, 
sized for nominal 5 abreast seating. Each airplane's powerplant 
includes two under-wing Pratt and Whitney PW1524G ultra-high bypass, 
geared turbofan engines. Flight controls are fly-by-wire flight with 
two passive/uncoupled side sticks. Avionics include five landscape 
primary cockpit displays. The dimension of the airplanes encompasses a 
wingspan of 115 feet; a height of 37.75 feet; and a length of 114.75 
feet for the Model BD-500-1A10 and 127 feet for the Model BD-500-1A11. 
Passenger capacity is designated as 110 for the Model BD-500-1A10 and 
125 for the Model BD-500-1A11. Maximum takeoff weight is 131,000 pounds 
for the Model BD-500-1A10 and 144,000 pounds for the Model BD-500-1A11. 
Maximum takeoff thrust is 21,000 pounds for the Model BD-500-1A10 and 
23,300 pounds for the Model BD-500-1A11. The range is 3,394 miles 
(5,463 kilometers) for both model airplanes. The maximum operating 
altitude is 41,000 feet for both model airplanes.
    The Bombardier BD-500-1A10 and BD-500-1A11 series airplanes will be 
fabricated using aluminum-lithium materials. The performance of 
airplanes 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-aluminum-lithium fuselage. Experience 
has shown that eliminating the fire propagation of the interior 
materials and insulation materials tends to increase survivability 
since other aspects of in-flight fire safety (e.g., toxic gas emission 
and smoke obscuration) are typically by-products of the propagating 
fire. The Bombardier BD-

[[Page 65232]]

500-1A10 and BD-500-1A11 series airplanes must provide protection 
against an in-flight fire propagating along the surface of the 
fuselage.

Type Certification Basis

    Under the provisions of Title 14, Code of Federal Regulations (14 
CFR) 21.17, Bombardier Inc. must show that the Model BD-500-1A10 and 
BD-500-1A11 series airplanes meet the applicable provisions of part 25 
as amended by Amendments 25-1 through 25-129 thereto.
    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-500-1A10 and BD-500-1A11 
series 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 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 BD-500-1A10 and BD-500-1A11 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 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 BD-500-1A10 and BD-500-1A11 series airplanes will 
incorporate the following novel or unusual design features: The 
fuselage will be fabricated using aluminum-lithium materials instead of 
conventional aluminum. This new type of material must provide 
protection against an in-flight fire propagating along the surface of 
the fuselage.

Discussion

    The Bombardier BD-500-1A10 and BD-500-1A11 series airplanes will be 
fabricated using aluminum-lithium materials. The performance of 
airplanes 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. 
Experience has shown that eliminating the fire propagation of the 
interior materials and insulation materials tends to increase 
survivability since other aspects of in-flight fire safety (e.g., toxic 
gas emission and smoke obscuration) are typically by-products of the 
propagating fire. The fuselage itself does not contribute to in-flight 
fire propagation. This may not be the case for an all-aluminum-lithium 
fuselage.
    In the past, fatal in-flight fires have originated in inaccessible 
areas of the airplane where thermal/acoustic insulation located 
adjacent to the aluminum airplane 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 that covered the thermal/acoustic insulation. 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).
    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. The current test standard at that time 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. A new test method subjecting a material to a pilot 
flame while the material is heated by a radiant panel was developed. 
The new radiant panel test method and criteria were specifically 
established to improve the evaluation of the in-flight fire ignition/
flame propagation of thermal/acoustic insulation materials based on 
real-world fire scenarios. While these tests were developed for 
thermal/acoustic insulation materials, this same type of test 
methodology can be used to assess the flammability characteristics of 
the proposed aluminum-lithium material for the fuselage.
    The FAA reviewed the test method proposed by Bombardier Inc. and 
determined that a larger flame and test article would be necessary to 
make a determination of the potential flammability of the aluminum-
lithium material. It would also be more representative of a real-life 
fire scenario.
    The FAA recently conducted additional testing in our Components 
Fire Test facility and determined that another way to assess the 
survivability within the cabin of the Model BD-500-1A10 and BD-500-1A11 
series is to use the cargo liner flammability test (part III of 
appendix F to part 25, Test Method to Determine Flame Penetration 
Resistance of Cargo Compartment Liners). However, the problem with 
using this particular test is that when the aluminum panels melt, 
molten globs of aluminum fall directly into the burner, which adversely 
affects the flame. So the FAA decided that a similar test for the 
measurement of insulation burnthrough resistance could be used (part 
VII of appendix F to part 25, Test Method to Determine the Burnthrough 
Resistance of Thermal/Acoustic Insulation Materials). Although this 
test method uses the same burner as the cargo liner test, it uses a 
slightly larger flame. In addition, the burner is not vertical, so 
there was no problem with molten material falling into it, requiring 
disassembly of the burner. The only slight change was the size of the 
sample and the sample holder. These were modified slightly to 
accommodate the samples that we received.
    The recent FAA tests that were conducted in our Components Fire 
Test facility used a 6 gallon/hour oil burner, the same apparatus used 
to determine burnthrough resistance of thermal/acoustic insulation 
(part VII of appendix F to part 25). The test used 16 by 24 inch Al-Li 
panels that were installed into a sheet steel subframe, which measured 
18 by 32 inches (outside dimensions). The subframe had an opening cut 
into it, which measured 14.5 by 22.5 inches; this allowed the test 
panels to be mounted onto the subframe using .250-20 UNC threaded 
bolts.
    The FAA proposes that Bombardier use the test method contained in 
part VII of appendix F to part 25, Test Method to Determine the 
Burnthrough Resistance of Thermal/Acoustic Insulation Materials, with 
the slight changes to the sample size and sample holder as an alternate 
test method to show compliance with applicable requirements. Bombardier 
Inc. is responsible for finding a suitable testing facility in which to 
conduct the testing.

Applicability

    As discussed above, these special conditions are applicable to the 
Model BD-500-1A10 and BD-500-1A11 airplanes. Should Bombardier 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.

[[Page 65233]]

Conclusion

    This action affects only certain novel or unusual design features 
on two models 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 Bombardier Inc. Model BD-500-1A10 and BD-500-1A11 series airplanes.
    1. Fuselage In-Flight Fire Safety and Flammability Resistance. 
Bombardier must demonstrate that the fuselage would not materially 
contribute to the propagation of an in-flight fire or introduce any 
additional in-flight fire risk.
    2. To demonstrate compliance, the test set-up and methodology must 
be commensurate with 14 CFR part 25, appendix F, part VII, except the 
size of the test samples, modifications to the sample holder, and the 
test methodology would be varied as described below.
    3. In demonstrating that the aluminum-lithium material used to 
fabricate the fuselage has equal or better flammability resistance 
characteristics than the aluminum alloy sheet typically used as skin 
material on similar airplanes, the accepted test methods for compliance 
include:
    a. Each test sample must consist of a flat test specimen. A set of 
three samples of the material must be tested. The size of each sample 
must be 16 inches by 24 inches by 0.063 inches.
    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 an opening cut into it of 14.5 inches by 22.5 inches. The tests 
samples must be mounted onto the subframe using .250-20 UNC threaded 
bolts.
    c. Test specimens must be conditioned at 70 [deg]F  5 
[deg]F and 55 percent  5 percent humidity for at least 24 
hours before testing.
    4. Demonstration of compliance will be achieved if the material is 
not ignited during any of the tests.

    Issued in Renton, Washington, on September 12, 2013.
Jeffrey E. Duven,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2013-25663 Filed 10-30-13; 8:45 am]
BILLING CODE 4910-13-P
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