Special Conditions: Bombardier Inc., Models BD-500-1A10 and BD-500-1A11 Series Airplanes; Fuselage In-Flight Fire Safety and Flammability Resistance, 9380-9382 [2014-03586]
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Federal Register / Vol. 79, No. 33 / Wednesday, February 19, 2014 / Rules and Regulations
characteristics of this non-traditional
fuselage material. If negligible amounts
of combustion products are produced in
this test, the material can be considered
acceptable with respect to post crash
survivability. A test method developed
by the FAA’s William J. Hughes
Technical Center should be used (Ref.
DOT/FAA/AR–TN07/15 dated August
2008).
Related regulations, including
§§ 25.853 and 25.856(a), remain valid
for this airplane, but they do not reflect
the potential threat generated from toxic
levels of gases produced from
aluminum-lithium materials.
constructed aluminum airplane exposed
to a post-crash fuel-fed fire.
Issued in Renton, Washington, on January
22, 2014.
Jeffrey E. Duven,
Manager, Transport Airplane Directorate,
Aircraft Certification Service.
[FR Doc. 2014–03585 Filed 2–18–14; 8:45 am]
BILLING CODE 4910–13–P
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
Discussion of Comments
Notice of proposed special conditions
No. 25–13–08–SC for the Bombardier Cseries airplanes was published in the
Federal Register on October 31, 2013
(78 FR 65233). No comments were
received, and the special conditions are
adopted as proposed.
[Docket No. FAA–2013–0819; Special
Conditions No. 25–519–SC]
Special Conditions: Bombardier Inc.,
Models BD–500–1A10 and BD–500–
1A11 Series Airplanes; Fuselage InFlight Fire Safety and Flammability
Resistance
Applicability
As discussed above, these special
conditions are applicable to the Models
BD–500–1A10 and BD–500–1A11 series
airplanes. Should Bombardier Inc. apply
at a later date for a change to the type
certificate to include another model on
the same type certificate 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 two
model series 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.
ehiers on DSK2VPTVN1PROD with RULES
The Special Conditions
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 Inc.
Models BD–500–1A10 and BD–500–
1A11 (C-series) airplanes.
Fuselage Post-Crash Fire
Survivability. The Bombardier C-series
airplanes must show that any toxic
levels of gases produced from the
aluminum-lithium material are in no
way an additional threat to the
passengers and their ability to evacuate
when compared to a typically
VerDate Mar<15>2010
14:22 Feb 18, 2014
Jkt 232001
Federal Aviation
Administration (FAA), DOT.
ACTION: Final special conditions.
AGENCY:
These special conditions are
issued for the Bombardier Inc. Models
BD–500–1A10 and BD–500–1A11 series
airplanes. These airplanes will have
novel or unusual design features when
compared to the state of technology
envisioned in the airworthiness
standards for transport category
airplanes. These features are 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 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: Effective Date: March 21, 2014.
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:
SUMMARY:
Background
On December 10, 2009, Bombardier
Inc. applied for a type certificate for
their new Models BD–500–1A10 and
BD–500–1A1 series airplanes (hereafter
collectively referred to as ‘‘C-series’’).
The C-series airplanes are swept-wing
PO 00000
Frm 00002
Fmt 4700
Sfmt 4700
monoplanes with an aluminum alloy
fuselage sized for 5-abreast seating.
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.
The Bombardier C-series airplanes
will be fabricated using aluminumlithium 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 Cseries 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 Cseries airplanes meet the applicable
provisions of part 25, as amended by
Amendment 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 C-series airplanes because of a
novel or unusual design feature, special
conditions are prescribed under the
provisions of § 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, the special conditions
would also apply to the other model
under § 21.101.
In addition to the applicable
airworthiness regulations and special
conditions, the C-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 § 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 § 11.38, and they become part of
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Federal Register / Vol. 79, No. 33 / Wednesday, February 19, 2014 / Rules and Regulations
the type-certification basis under
§ 21.17(a)(2).
ehiers on DSK2VPTVN1PROD with RULES
Novel or Unusual Design Features
The Bombardier C-series airplanes
will incorporate the following novel or
unusual design features: The fuselage
will be fabricated using aluminumlithium 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 C-series airplanes
will be fabricated using aluminumlithium 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
VerDate Mar<15>2010
14:22 Feb 18, 2014
Jkt 232001
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 C-series
airplanes 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 24inch 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
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Frm 00003
Fmt 4700
Sfmt 4700
9381
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.
Discussion of Comments
Notice of proposed special conditions
No. 25–13–06–SC for the Bombardier Cseries airplanes was published in the
Federal Register on October 31, 2013
(78 FR 65231). No comments were
received, and the special conditions are
adopted as proposed.
Applicability
As discussed above, these special
conditions are applicable to the Models
BD–500–1A10 and BD–500–1A11 series
airplanes. Should Bombardier Inc. apply
at a later date for a change to the type
certificate to include another model on
the same type certificate 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 two
model series 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 Special Conditions
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 Inc.
Models BD–500–1A10 and BD–500–
1A11 (C-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.
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Federal Register / Vol. 79, No. 33 / Wednesday, February 19, 2014 / Rules and Regulations
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 °F ± 5 °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 January
22, 2014.
Jeffrey E. Duven,
Manager, Transport Airplane Directorate,
Aircraft Certification Service.
[FR Doc. 2014–03586 Filed 2–18–14; 8:45 am]
BILLING CODE 4910–13–P
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA–2013–0632; Directorate
Identifier 2013–NM–045–AD; Amendment
39–17752; AD 2014–03–14]
Discussion
RIN 2120–AA64
Airworthiness Directives; Airbus
Airplanes
Federal Aviation
Administration (FAA), Department of
Transportation (DOT).
ACTION: Final rule.
AGENCY:
We are adopting a new
airworthiness directive (AD) for all
Airbus Model A330–200 and –300 series
airplanes, and Model A340–200, –300,
–500, and –600 series airplanes. This
AD was prompted by results from fuel
system reviews conducted by the
airplane manufacturer. This AD requires
removing bulb-type maintenance lights;
installing a drain mast on certain
airplanes; and installing muffs on
connecting bleed elements on certain
airplanes. We are issuing this AD to
ehiers on DSK2VPTVN1PROD with RULES
SUMMARY:
VerDate Mar<15>2010
14:22 Feb 18, 2014
Jkt 232001
prevent ignition sources inside fuel
tanks, which, in combination with
flammable fuel vapors, could result in
fuel tank explosions and consequent
loss of the airplane.
DATES: This AD becomes effective
March 26, 2014.
The Director of the Federal Register
approved the incorporation by reference
of certain publications listed in this AD
as of March 26, 2014.
ADDRESSES: You may examine the AD
docket on the Internet at https://
www.regulations.gov/
#!docketDetail;D=FAA-2013-0632; or in
person at the Docket Management
Facility, U.S. Department of
Transportation, Docket Operations, M–
30, West Building Ground Floor, Room
W12–140, 1200 New Jersey Avenue SE.,
Washington, DC.
For service information identified in
this AD, contact Airbus SAS,
Airworthiness Office—EAL, 1 Rond
Point Maurice Bellonte, 31707 Blagnac
Cedex, France; telephone +33 5 61 93 36
96; fax +33 5 61 93 45 80; email
airworthiness.A330-A340@airbus.com;
Internet https://www.airbus.com. You
may view this referenced service
information at the FAA, Transport
Airplane Directorate, 1601 Lind Avenue
SW., Renton, WA. For information on
the availability of this material at the
FAA, call 425–227–1221.
FOR FURTHER INFORMATION CONTACT:
Vladimir Ulyanov, Aerospace Engineer,
International Branch, ANM–116,
Transport Airplane Directorate, FAA,
1601 Lind Avenue SW., Renton, WA
98057–3356; telephone 425–227–1138;
fax 425–227–1149.
SUPPLEMENTARY INFORMATION:
We issued a notice of proposed
rulemaking (NPRM) to amend 14 CFR
part 39 by adding an AD that would
apply to all Airbus Model A330–200
and –300 series airplanes, and Model
A340–200, –300, –500, and –600 series
airplanes. The NPRM published in the
Federal Register on July 31, 2013 (78 FR
46306). The NPRM was prompted by
results from fuel system reviews
conducted by the airplane
manufacturer. The NPRM proposed to
require removing bulb-type
maintenance lights; installing a drain
mast on certain airplanes; and installing
muffs on connecting bleed elements on
certain airplanes. We are issuing this
AD to prevent ignition sources inside
fuel tanks, which, in combination with
flammable fuel vapors, could result in
fuel tank explosions and consequent
loss of the airplane.
PO 00000
Frm 00004
Fmt 4700
Sfmt 4700
The European Aviation Safety Agency
(EASA), which is the Technical Agent
for the Member States of the European
Community, has issued EASA
Airworthiness Directive 2013–0033,
dated February 19, 2013 (referred to
after this the Mandatory Continuing
Airworthiness Information, or ‘‘the
MCAI’’), to correct an unsafe condition
for the specified products. The MCAI
states:
[Subsequent to accidents involving fuel
tank system explosions in flight and on
ground], the FAA published Special Federal
Aviation Regulation (SFAR) 88 [66FR 23086,
May 7, 2001], and the Joint Aviation
Authorities (JAA) published Interim Policy
INT/POL/25/12.
In response to these regulations, a global
design review conducted by Airbus on the
A330 and A340 type design Section 19,
which is a flammable fluid leakage zone and
a zone adjacent to a fuel tank, highlighted
potential deviations. The specific identified
cases were that drainage is inefficient in
flight on A340–500/–600 aeroplanes,
maintenance lights are not qualified
explosion proof, and hot surfaces may exist
on bleed system during normal/failure
operations.
This condition, if not corrected, in
combination with a fuel leak generating
flammable vapours in the area, could result
in a fuel tank explosion and consequent loss
of the aeroplane.
For the reasons described above, this
[EASA] AD requires removal of bulb type
maintenance lights for all aeroplanes,
installation of the drain mast between Frame
(FR) 80 and FR83 for A340–500/–600, and
installation of muffs on connecting bleed
elements to minimize hot surfaces on A330
and A340–200/–300.
You may examine the MCAI in the
AD docket on the Internet at https://
www.regulations.gov/
#!documentDetail;D=FAA-2013-06320002.
Comments
We gave the public the opportunity to
participate in developing this AD. We
have considered the comments received.
The following presents the comments
received on the proposal (78 FR 46306,
July 31, 2013) and the FAA’s response
to each comment.
Request To Require New Service
Information
Airbus requested that we specify the
use of Revision 01 of Airbus Mandatory
Service Bulletin A340–36–4035, dated
September 24, 2013, instead of the
original issue of Airbus Mandatory
Service Bulletin A340–36–4035, dated
September 18, 2012. Airbus stated that
since the issuance of the MCAI, it
identified an inversion of configurations
in Airbus Mandatory Service Bulletin
A340–36–4035. Airbus stated that it
E:\FR\FM\19FER1.SGM
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]]>Agencies
[Federal Register Volume 79, Number 33 (Wednesday, February 19, 2014)]
[Rules and Regulations]
[Pages 9380-9382]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2014-03586]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. FAA-2013-0819; Special Conditions No. 25-519-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: Final special conditions.
-----------------------------------------------------------------------
SUMMARY: These special conditions are issued for the Bombardier Inc.
Models BD-500-1A10 and BD-500-1A11 series airplanes. These airplanes
will have novel or unusual design features when compared to the state
of technology envisioned in the airworthiness standards for transport
category airplanes. These features are 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 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: Effective Date: March 21, 2014.
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:
Background
On December 10, 2009, Bombardier Inc. applied for a type
certificate for their new Models BD-500-1A10 and BD-500-1A1 series
airplanes (hereafter collectively referred to as ``C-series''). The C-
series airplanes are swept-wing monoplanes with an aluminum alloy
fuselage sized for 5-abreast seating. 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.
The Bombardier C-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 C-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 C-series airplanes meet
the applicable provisions of part 25, as amended by Amendment 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 C-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 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 C-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
[[Page 9381]]
the type-certification basis under Sec. 21.17(a)(2).
Novel or Unusual Design Features
The Bombardier C-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 C-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 C-series airplanes 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.
Discussion of Comments
Notice of proposed special conditions No. 25-13-06-SC for the
Bombardier C-series airplanes was published in the Federal Register on
October 31, 2013 (78 FR 65231). No comments were received, and the
special conditions are adopted as proposed.
Applicability
As discussed above, these special conditions are applicable to the
Models BD-500-1A10 and BD-500-1A11 series airplanes. Should Bombardier
Inc. apply at a later date for a change to the type certificate to
include another model on the same type certificate 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 two model series 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 Special Conditions
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 Inc. Models BD-500-1A10 and
BD-500-1A11 (C-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.
[[Page 9382]]
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 January 22, 2014.
Jeffrey E. Duven,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 2014-03586 Filed 2-18-14; 8:45 am]
BILLING CODE 4910-13-P
