Special Conditions: Boeing Model 787-8 Airplane; Composite Fuselage In-Flight Fire/Flammability Resistance, 45626-45628 [E7-16020]
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Federal Register / Vol. 72, No. 157 / Wednesday, August 15, 2007 / Rules and Regulations
ebenthall on PRODPC61 with RULES
conditions are issued as part of the type
certification basis for Adam Aircraft,
Model A700 airplanes.
Aft fuselage mounted engines need to
protect the airplane from fires that were
not envisioned in the development of
part 23. Therefore, special conditions
for a fire extinguishing system are
required for airplanes with this engine
configuration.
Regulations requiring and defining
engine compartment fire extinguishing
systems already exist for part 23
commuter category airplanes. These
regulations will provide an adequate
level of safety for the normal category
Model A700 aircraft with its aft pylon
mounted engines.
As the extinguishing agent is subject
to change during the service life of the
airplane, the certification basis needs to
include 14 CFR part 23, § 23.1197 in its
entirety.
Each fire zone should be ventilated to
prevent the accumulation of flammable
vapors. It must also be designed such
that it will not allow entry of flammable
fluids, vapors, or flames from other fire
zones. It must be designed such that it
does not create an additional fire hazard
from the discharge of vapors or fluids.
1. SC 23.1195—Add the requirements
of § 23.1195 while deleting ‘‘For
commuter category airplanes.’’
23.1195, Fire Extinguishing Systems
(a) Fire extinguishing systems must be
installed and compliance shown with
the following:
(1) Except for combustor, turbine, and
tailpipe sections of turbine-engine
installations that contain lines or
components carrying flammable fluids
or gases for which a fire originating in
these sections is shown to be
controllable, a fire extinguisher system
must serve each engine compartment;
(2) The fire extinguishing system, the
quantity of extinguishing agent, the rate
of discharge, and the discharge
distribution must be adequate to
extinguish fires. An individual ‘‘oneshot’’ system may be used except for
embedded engines where a ‘‘two-shot’’
system is required.
(3) The fire extinguishing system for
a nacelle must be able to simultaneously
protect each compartment of the nacelle
for which protection is provided.
(b) If an auxiliary power unit is
installed in any airplane certificated to
this part, that auxiliary power unit
compartment must be served by a fire
extinguishing system meeting the
requirements of paragraph (a)(2) of this
section.
2. SC 23.1197—Add the requirements
of § 23.1197 while deleting ‘‘For
commuter category airplanes.’’
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Jkt 211001
23.1197, Fire Extinguishing Agents
The following applies:
(a) Fire extinguishing agents must—
(1) Be capable of extinguishing flames
emanating from any burning fluids or
other combustible materials in the area
protected by the fire extinguishing
system; and
(2) Have thermal stability over the
temperature range likely to be
experienced in the compartment in
which they are stored.
(b) If any toxic extinguishing agent is
used, provisions must be made to
prevent harmful concentrations of fluid
or fluid vapors (from leakage during
normal operation of the airplane or as a
result of discharging the fire
extinguisher on the ground or in flight)
from entering any personnel
compartment, even though a defect may
exist in the extinguishing system. This
must be shown by test except for builtin carbon dioxide fuselage compartment
fire extinguishing systems for which—
(1) Five pounds or less of carbon
dioxide will be discharged under
established fire control procedures into
any fuselage compartment; or
(2) Protective breathing equipment is
available for each flight crewmember on
flight deck duty.
3. SC 23.1199—Add the requirements
of § 23.1199 while deleting ‘‘For
commuter category airplanes.’’
23.1199, Extinguishing Agent
Containers
Frm 00016
Fmt 4700
Sfmt 4700
23.1201, Fire Extinguishing System
Materials
The following apply:
(a) No material in any fire
extinguishing system may react
chemically with any extinguishing agent
so as to create a hazard.
(b) Each system component in an
engine compartment must be fireproof.
Issued in Kansas City, Missouri on
August 6, 2007.
Kim Smith,
Manager, Small Airplane Directorate, Aircraft
Certification Service.
[FR Doc. E7–15973 Filed 8–14–07; 8:45 am]
BILLING CODE 4910–13–P
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. NM373; Special Conditions No.
25–360–SC]
Special Conditions: Boeing Model 787–
8 Airplane; Composite Fuselage InFlight Fire/Flammability Resistance
Federal Aviation
Administration (FAA), DOT.
ACTION: Final special conditions.
AGENCY:
The following applies:
(a) Each extinguishing agent container
must have a pressure relief to prevent
bursting of the container by excessive
internal pressures.
(b) The discharge end of each
discharge line from a pressure relief
connection must be located so that
discharge of the fire-extinguishing agent
would not damage the airplane. The line
must also be located or protected to
prevent clogging caused by ice or other
foreign matter.
(c) A means must be provided for
each fire extinguishing agent container
to indicate that the container has
discharged or that the charging pressure
is below the established minimum
necessary for proper functioning.
(d) The temperature of each container
must be maintained, under intended
operating conditions, to prevent the
pressure in the container from—
(1) Falling below that necessary to
provide an adequate rate of discharge; or
(2) Rising high enough to cause
premature discharge.
(e) If a pyrotechnic capsule is used to
discharge the fire extinguishing agent,
each container must be installed so that
PO 00000
temperature conditions will not cause
hazardous deterioration of the
pyrotechnic capsule.
4. SC 23.1201—Add the requirements
of § 23.1201 while deleting ‘‘For
commuter category airplanes.’’
SUMMARY: These special conditions are
issued for the Boeing Model 787–8
airplane. This airplane will have novel
or unusual design features when
compared to the state of technology
envisioned in the airworthiness
standards for transport category
airplanes. The fuselage of the Boeing
Model 787–8 series airplane will be
made of composite materials rather than
conventional aluminum. While the
regulations include flame propagation
standards for some materials commonly
found in inaccessible areas of the
airplane, they do not yet incorporate
standards for materials used to construct
the fuselage. Therefore, special
conditions are needed to address 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 standards. Additional special
conditions will be issued for other novel
or unusual design features of the Boeing
Model 787–8 airplanes.
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Federal Register / Vol. 72, No. 157 / Wednesday, August 15, 2007 / Rules and Regulations
DATES:
Effective Date: September 14,
2007.
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:
FOR FURTHER INFORMATION CONTACT:
Background
On March 28, 2003, Boeing applied
for an FAA type certificate for its new
Boeing Model 787–8 passenger airplane.
The Boeing Model 787–8 airplane will
be an all-new, two-engine jet transport
airplane with a two-aisle cabin. The
maximum takeoff weight will be
476,000 pounds, with a maximum
passenger count of 381 passengers.
ebenthall on PRODPC61 with RULES
Type Certification Basis
Under provisions of 14 Code of
Federal Regulations (CFR) 21.17, Boeing
must show that Boeing Model 787–8
airplanes (hereafter referred to as ‘‘the
787’’) meet the applicable provisions of
14 CFR part 25, as amended by
Amendments 25–1 through 25–117,
except §§ 25.809(a) and 25.812, which
will remain at Amendment 25–115. If
the Administrator finds that the
applicable airworthiness regulations do
not contain adequate or appropriate
safety standards for the 787 because of
a novel or unusual design feature,
special conditions are prescribed under
provisions of 14 CFR 21.16.
In addition to the applicable
airworthiness regulations and special
conditions, the 787 must comply with
the fuel vent and exhaust emission
requirements of 14 CFR part 34 and the
noise certification requirements of part
36. The FAA must also issue a finding
of regulatory adequacy pursuant to
section 611 of Public Law 92–574, the
‘‘Noise Control Act of 1972.’’
The FAA issues special conditions, as
defined in § 11.19, under § 11.38, and
they become part of the type
certification basis under § 21.17(a)(2).
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 § 21.101.
Novel or Unusual Design Features
In-flight fires have originated in
inaccessible areas of aircraft where
thermal/acoustic insulation located
VerDate Aug<31>2005
14:56 Aug 14, 2007
Jkt 211001
adjacent to the aluminum aircraft skin
has been the path for flame propagation
and fire growth. Although these
insulation materials were required to
comply with the basic ‘‘Bunsen burner’’
requirements of 14 CFR 25.853(a) and
25.855(d), these incidents revealed
unexpected flame spread along the
insulation film covering material of the
thermal/acoustic insulation. In all cases,
the ignition source was relatively
modest and, in most cases, was
electrical in origin (for example an
electrical short circuit, arcing caused by
chafed wiring, or a ruptured ballast
case).
In September 2003, in an effort to
limit use of materials that sustain or
propagate a fire in inaccessible areas,
the FAA promulgated 14 CFR 25.856(a),
which requires that thermal/acoustic
insulation material installed in the
fuselage meet newly developed flame
propagation test requirements. That rule
was Amendment 25–111. These
requirements were developed to address
a realistic fire threat. We consider that
threat generally applicable to the 787.
Conventional aluminum fuselage
material does not contribute to in-flight
fire propagation. As a result, there are
no standards that address in-flight fire
safety of the fuselage structure itself.
The 787 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.
As a result of this extensive use of a
new construction material, the fuselage
cannot be assumed to have the fire
resistance previously afforded by
aluminum during the in-flight fire
scenario mentioned above. These
special conditions require that the 787
provide the same level of in-flight
survivability as a conventional
aluminum fuselage airplane. This
includes its thermal/acoustic insulation
meeting the requirements of § 25.856(a).
Resistance to flame propagation must be
shown, and all products of combustion
that may result must be evaluated for
toxicity and found acceptable.
Discussion of Comments
Notice of Proposed Special
Conditions No. 25–07–09–SC for the
787 was published in the Federal
Register on April 26, 2007 (72 FR
20774). Two commenters, the Air Line
Pilots Association (ALPA) and an
individual member of the public,
responded to the notice. Both
commenters concur with the proposed
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Fmt 4700
Sfmt 4700
45627
special conditions but have additional
concerns about composite structures
that they feel should be addressed.
Comment 1. A member of the public
commented that a post-crash, fuel fed
fire is a significant hazard that is not
addressed in these special conditions.
This commenter cites research
conducted on behalf of the Australian
Government that documents potential
fire hazards associated with composite
materials—in particular toxicity and
smoke. The commenter noted that the
fire penetration resistance of a
composite material alone is not
sufficient to determine its overall
contribution to fire safety.
FAA Response: We agree with the
commenter that consideration of postcrash fire safety must include all the
factors that influence survivability, and
not just focus on one characteristic.
These special conditions focus on inflight fire safety, so any issues related to
post-crash fire safety go beyond the
scope of these special conditions.
Nonetheless, the FAA is equally
concerned with post-crash survivability
and is addressing this issue through
separate criteria. In this case, because
there are requirements related to postcrash fire safety in § 25.856(b), the
approach will be via an equivalent level
of safety finding in accordance with
§ 21.21(b)(1). A summary of this finding
will be available in the FAA Regulatory
and Guidance Library at https://
rgl.faa.gov/.
Comment 2. ALPA commented that
the effects of moisture ingress must be
addressed for all aspects of composite
material integrity.
FAA Response: From the standpoint
of flammability, moisture ingress is not
an issue, because moisture will tend to
reduce the flammability of the material.
Since these special conditions only
concern flammability resulting from an
in-flight fire, the remainder of the issues
go beyond the scope of these special
conditions. Moisture is known to
influence properties of composite
materials and this concern is a well
documented environmental condition
that Boeing will have to address. In fact,
the use of composite materials in
aviation is not new and there is a
significant amount of experience with
the behavior of composites over time in
service. Advisory Circular 20–107A,
Composite Aircraft Structure, also
discusses factors that need to be
addressed when using composite
structure.
Comment 3. ALPA also commented
that aluminum structure can dissipate
heat using the airflow over the skin, but
this may not be the case for a composite
structure because of its different thermal
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15AUR1
45628
Federal Register / Vol. 72, No. 157 / Wednesday, August 15, 2007 / Rules and Regulations
conductivity. ALPA believes that this
difference must be taken into account
with any in-flight fire safety assessment.
FAA Response: We agree that the heat
transfer characteristics of aluminum
influence its response to an in-flight
fire, and that a composite structure will
doubtless behave differently. The goal of
these special conditions is to enable
continued safe flight and landing in the
event of an in-flight fire that directly
impinges on the fuselage structure.
Since these special conditions require
Boeing to show that the composite
structure is resistant to flame
propagation resulting from in-flight fire,
all the relevant material properties and
performance characteristics of the
composite structure will need to be
addressed. This requirement is not a
comparison with aluminum structure. It
is a new requirement for composite
structure. Since this is so, the special
conditions as written cover the ALPA
concern, and these special conditions
are adopted as proposed.
Applicability
As discussed above, these special
conditions are applicable to the 787.
Should Boeing 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 features, these special
conditions would apply to that model as
well.
Conclusion
This action affects only certain novel
or unusual design features of the 787. 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 the Boeing Model 787–8
airplane.
I In addition to the requirements of 14
CFR 25.853(a) governing material
flammability, the following special
conditions apply:
ebenthall on PRODPC61 with RULES
I
The 787–8 composite fuselage structure
must be shown to be resistant to flame
propagation under the fire threat used to
develop 14 CFR 25.856(a). If products of
combustion are observed beyond the test heat
source, they must be evaluated and found
acceptable.
VerDate Aug<31>2005
14:56 Aug 14, 2007
Jkt 211001
Issued in Renton, Washington, on August
6, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate,
Aircraft Certification Service.
[FR Doc. E7–16020 Filed 8–14–07; 8:45 am]
BILLING CODE 4910–13–P
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 71
[Docket No. FAA–2007–28669; Airspace
Docket No. 07–ASO–18]
Removal of Class E Airspace;
Columbus, GA
Federal Aviation
Administration (FAA), DOT.
ACTION: Final rule.
AGENCY:
SUMMARY: This action removes the Class
E4 Airspace at Columbus Lawson Army
Air Field (AAF), Columbus, Ga. This
Class E4 airspace was associated with a
Nondirectional Radio Beacon (NDB)
Runway (RWY) 03 Standard Instrument
Approach Procedure (SIAP), which has
been cancelled, as RWY 03–21 has been
permanently closed.
DATES: Effective Date: 0901 UTC,
October 25, 2007. The Director of the
Federal Register approves this
incorporation by reference action under
title 1, Code of Federal Regulations, part
51, subject to the annual revision of
FAA Order 7400.9 and publication of
conforming amendments.
FOR FURTHER INFORMATION CONTACT:
Mark D. Ward, Manager, System
Support Group, Eastern Service Center,
Federal Aviation Administration, P.O.
Box 20636, Atlanta, Georgia 30320;
telephone (404) 305–5581.
SUPPLEMENTARY INFORMATION:
History
The NDB RWY 03 SIAP was cancelled
due to the permanent closure of RWY
03–21. The cancellation and runway
closure, therefore, requires the removal
of Class E4 airspace. This rule becomes
effective on the date specified in the
‘‘Effective Date’’ section. Since this
action will eliminate the impact of
controlled airspace on aircraft in the
vicinity of Columbus Lawson AAF, GA,
notice and public procedure under 5
U.S.C. 553(b) are not necessary.
Designations for Class E airspace areas
extending upward from the surface of
the earth are published in Paragraph
6004 of FAA Order 7400.9P, dated
September 01, 2006, and effective
September 15, 2006, which is
incorporated by reference in 14 CFR
PO 00000
Frm 00018
Fmt 4700
Sfmt 4700
71.1. The Class E airspace designations
listed in this document will be
published subsequently in the Order.
The Rule
This amendment to Title 14 Code of
Federal Regulations (14 CFR) part 71
removes Class E4 airspace at Lawson
AAF, Columbus, Ga.
The FAA has determined that this
regulation only involves an established
body of technical regulations for which
frequent and routine amendments are
necessary to keep them operationally
current. It, therefore, (1) is not a
‘‘significant regulatory action’’ under
Executive Order 12866; (2) is not a
‘‘significant rule’’ under DOT
Regulatory Policies and Procedures (44
FR 11034; February 26, 1979); and (3)
does not warrant preparation of a
regulatory evaluation as the anticipated
impact is so minimal. Since this is a
routine matter that will only affect air
traffic procedures and air navigation, it
is certified that this rule will not have
a significant economic impact on a
substantial number of small entities
under the criteria of the Regulatory
Flexibility Act.
List of Subjects in 14 CFR Part 71
Airspace, Incorporation by reference,
Navigation (air).
Adoption of the Amendment
In consideration of the foregoing, the
Federal Aviation Administration
amends 14 CFR part 71 as follows:
I
PART 71—[AMENDED]
1. The authority citation for 14 CFR
part 71 continues to read as follows:
I
Authority: 49 U.S.C. 106(g); 40103, 40113,
40120; EO 10854, 24 FR 9565, 3 CFR, 1959–
1963 Comp., p. 389; 14 CFR 11.69.
§ 71.1
[Amended]
2. The incorporation by reference in
14 CFR 71.1 of Federal Aviation
Administration Order 7400.9P, Airspace
Designations and Reporting Points,
dated September 1, 2006, and effective
September 15, 2006, is amended as
follows:
I
Paragraph 6004 Class E Airspace Areas
Designated as an Extension to a Class D
Surface Area.
*
*
*
*
*
ASO GA E4 Columbia Lawson AAF, GA
[REMOVED]
*
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*
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*
*
]]>Agencies
[Federal Register Volume 72, Number 157 (Wednesday, August 15, 2007)]
[Rules and Regulations]
[Pages 45626-45628]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E7-16020]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. NM373; Special Conditions No. 25-360-SC]
Special Conditions: Boeing Model 787-8 Airplane; Composite
Fuselage In-Flight Fire/Flammability Resistance
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final special conditions.
-----------------------------------------------------------------------
SUMMARY: These special conditions are issued for the Boeing Model 787-8
airplane. This airplane will have novel or unusual design features when
compared to the state of technology envisioned in the airworthiness
standards for transport category airplanes. The fuselage of the Boeing
Model 787-8 series airplane will be made of composite materials rather
than conventional aluminum. While the regulations include flame
propagation standards for some materials commonly found in inaccessible
areas of the airplane, they do not yet incorporate standards for
materials used to construct the fuselage. Therefore, special conditions
are needed to address 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 standards. Additional special conditions
will be issued for other novel or unusual design features of the Boeing
Model 787-8 airplanes.
[[Page 45627]]
DATES: Effective Date: September 14, 2007.
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:
Background
On March 28, 2003, Boeing applied for an FAA type certificate for
its new Boeing Model 787-8 passenger airplane. The Boeing Model 787-8
airplane will be an all-new, two-engine jet transport airplane with a
two-aisle cabin. The maximum takeoff weight will be 476,000 pounds,
with a maximum passenger count of 381 passengers.
Type Certification Basis
Under provisions of 14 Code of Federal Regulations (CFR) 21.17,
Boeing must show that Boeing Model 787-8 airplanes (hereafter referred
to as ``the 787'') meet the applicable provisions of 14 CFR part 25, as
amended by Amendments 25-1 through 25-117, except Sec. Sec. 25.809(a)
and 25.812, which will remain at Amendment 25-115. If the Administrator
finds that the applicable airworthiness regulations do not contain
adequate or appropriate safety standards for the 787 because of a novel
or unusual design feature, special conditions are prescribed under
provisions of 14 CFR 21.16.
In addition to the applicable airworthiness regulations and special
conditions, the 787 must comply with the fuel vent and exhaust emission
requirements of 14 CFR part 34 and the noise certification requirements
of part 36. The FAA must also issue a finding of regulatory adequacy
pursuant to section 611 of Public Law 92-574, the ``Noise Control Act
of 1972.''
The FAA issues special conditions, as defined in Sec. 11.19, under
Sec. 11.38, and they become part of the type certification basis under
Sec. 21.17(a)(2).
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.
Novel or Unusual Design Features
In-flight fires have originated in inaccessible areas of aircraft
where thermal/acoustic insulation located adjacent to the aluminum
aircraft skin has been the path for flame propagation and fire growth.
Although these insulation materials were required to comply with the
basic ``Bunsen burner'' requirements of 14 CFR 25.853(a) and 25.855(d),
these incidents revealed unexpected flame spread along the insulation
film covering material of the thermal/acoustic insulation. In all
cases, the ignition source was relatively modest and, in most cases,
was electrical in origin (for example an electrical short circuit,
arcing caused by chafed wiring, or a ruptured ballast case).
In September 2003, in an effort to limit use of materials that
sustain or propagate a fire in inaccessible areas, the FAA promulgated
14 CFR 25.856(a), which requires that thermal/acoustic insulation
material installed in the fuselage meet newly developed flame
propagation test requirements. That rule was Amendment 25-111. These
requirements were developed to address a realistic fire threat. We
consider that threat generally applicable to the 787.
Conventional aluminum fuselage material does not contribute to in-
flight fire propagation. As a result, there are no standards that
address in-flight fire safety of the fuselage structure itself. The 787
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.
As a result of this extensive use of a new construction material,
the fuselage cannot be assumed to have the fire resistance previously
afforded by aluminum during the in-flight fire scenario mentioned
above. These special conditions require that the 787 provide the same
level of in-flight survivability as a conventional aluminum fuselage
airplane. This includes its thermal/acoustic insulation meeting the
requirements of Sec. 25.856(a). Resistance to flame propagation must
be shown, and all products of combustion that may result must be
evaluated for toxicity and found acceptable.
Discussion of Comments
Notice of Proposed Special Conditions No. 25-07-09-SC for the 787
was published in the Federal Register on April 26, 2007 (72 FR 20774).
Two commenters, the Air Line Pilots Association (ALPA) and an
individual member of the public, responded to the notice. Both
commenters concur with the proposed special conditions but have
additional concerns about composite structures that they feel should be
addressed.
Comment 1. A member of the public commented that a post-crash, fuel
fed fire is a significant hazard that is not addressed in these special
conditions. This commenter cites research conducted on behalf of the
Australian Government that documents potential fire hazards associated
with composite materials--in particular toxicity and smoke. The
commenter noted that the fire penetration resistance of a composite
material alone is not sufficient to determine its overall contribution
to fire safety.
FAA Response: We agree with the commenter that consideration of
post-crash fire safety must include all the factors that influence
survivability, and not just focus on one characteristic. These special
conditions focus on in-flight fire safety, so any issues related to
post-crash fire safety go beyond the scope of these special conditions.
Nonetheless, the FAA is equally concerned with post-crash survivability
and is addressing this issue through separate criteria. In this case,
because there are requirements related to post-crash fire safety in
Sec. 25.856(b), the approach will be via an equivalent level of safety
finding in accordance with Sec. 21.21(b)(1). A summary of this finding
will be available in the FAA Regulatory and Guidance Library at https://
rgl.faa.gov/.
Comment 2. ALPA commented that the effects of moisture ingress must
be addressed for all aspects of composite material integrity.
FAA Response: From the standpoint of flammability, moisture ingress
is not an issue, because moisture will tend to reduce the flammability
of the material. Since these special conditions only concern
flammability resulting from an in-flight fire, the remainder of the
issues go beyond the scope of these special conditions. Moisture is
known to influence properties of composite materials and this concern
is a well documented environmental condition that Boeing will have to
address. In fact, the use of composite materials in aviation is not new
and there is a significant amount of experience with the behavior of
composites over time in service. Advisory Circular 20-107A, Composite
Aircraft Structure, also discusses factors that need to be addressed
when using composite structure.
Comment 3. ALPA also commented that aluminum structure can
dissipate heat using the airflow over the skin, but this may not be the
case for a composite structure because of its different thermal
[[Page 45628]]
conductivity. ALPA believes that this difference must be taken into
account with any in-flight fire safety assessment.
FAA Response: We agree that the heat transfer characteristics of
aluminum influence its response to an in-flight fire, and that a
composite structure will doubtless behave differently. The goal of
these special conditions is to enable continued safe flight and landing
in the event of an in-flight fire that directly impinges on the
fuselage structure. Since these special conditions require Boeing to
show that the composite structure is resistant to flame propagation
resulting from in-flight fire, all the relevant material properties and
performance characteristics of the composite structure will need to be
addressed. This requirement is not a comparison with aluminum
structure. It is a new requirement for composite structure. Since this
is so, the special conditions as written cover the ALPA concern, and
these special conditions are adopted as proposed.
Applicability
As discussed above, these special conditions are applicable to the
787. Should Boeing 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 features, these special
conditions would apply to that model as well.
Conclusion
This action affects only certain novel or unusual design features
of the 787. 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
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 the Boeing Model 787-8 airplane.
0
In addition to the requirements of 14 CFR 25.853(a) governing material
flammability, the following special conditions apply:
The 787-8 composite fuselage structure must be shown to be
resistant to flame propagation under the fire threat used to develop
14 CFR 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 August 6, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E7-16020 Filed 8-14-07; 8:45 am]
BILLING CODE 4910-13-P
