[Federal Register: June 4, 2009 (Volume 74, Number 106)]
[Notices]
[Page 26919-26920]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr04jn09-133]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of request for comments on nonmetallic transport
category airplanes.
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SUMMARY: This notice solicits public comment on the need for, and the
possible scope of, rulemaking to address extensive use of nonmetallic
materials in the construction of transport category airplanes.
DATES: We must receive comments on this notice by September 2, 2009.
ADDRESSES: You may mail comments to: Federal Aviation Administration
(FAA), Transport Airplane Directorate, Aircraft Certification Service,
ANM-100 (Attn: Jeff Gardlin, ANM-115), 1601 Lind Avenue, SW., Renton,
Washington 98057-3359.
FOR FURTHER INFORMATION CONTACT: Jeff Gardlin, FAA, Airframe and Cabin
Safety Branch, ANM-115, Transport Airplane Directorate, Aircraft
Certification Service, 1601 Lind Avenue, SW., Renton, Washington 98057-
3359; telephone (206) 227-2136.
[[Page 26920]]
SUPPLEMENTARY INFORMATION:
Comments Invited
Interested persons are invited to participate in identifying the
need for, and defining the scope of, rulemaking and advisory materials
to address the extensive use of nonmetallic materials in the
construction of transport category airplanes by submitting written
data, views, or arguments as they may desire. Comments relating to the
environmental, energy, or economic impact that might result from
adopting the recommendations contained in this notice are invited.
Substantive comments should be accompanied by estimates of their
economic impact if possible. All comments received on or before the
closing date for comments will be considered by the FAA before deciding
whether to pursue rulemaking.
Background
The certification standards for transport category airplanes are
contained in Title 14, Code of Federal Regulations (14 CFR) part 25.
These standards have evolved over the years and take into account the
practicalities of how airplanes are designed and constructed. While it
is in theory possible to develop standards that make no assumptions
about the airplane design or materials, i.e., pure performance
standards, this is often extremely difficult. The standards themselves
would have to anticipate virtually any design innovations, which would
tend to make the standards very complex and lengthy or, conversely, so
high level as to make it difficult to develop methods for demonstrating
compliance. One area where the airworthiness standards of part 25 are
based on an assumption is the principal materials of construction. For
the most part, the regulations assume that the airplane fuselage,
including wings and empennage--the airframe--will be constructed from
metallic materials. Despite this assumption, nonmetallic materials have
been used over the years for specific components on various airplane
types. In those cases, the FAA has evaluated the safety effects of
these specific designs, and in some cases has issued special conditions
to identify appropriate certification criteria. However, the current
regulatory standards do not account for an airframe that is constructed
predominantly from nonmetallic materials. While special conditions are
a tool to address individual certification projects, they are not a
long-term solution to a shift in design philosophy. Airworthiness
standards might need to evolve with evolving designs. Therefore, the
FAA is considering whether a more comprehensive change to part 25 is
appropriate.
There is an obvious trend toward the increased use of composites in
the construction of airplanes. Both Boeing and Airbus are in the
process of developing large transport category airplanes using
composite materials as the primary material in construction of the
airframe. The FAA has written, or is in the process of writing, special
conditions to incorporate adequate safety standards for these
airplanes. Some of the special conditions supplement or replace
requirements that either do not address all aspects of composites, or
have criteria that are based on experience with metallic structure that
is not applicable to composites. In either situation, the use of
nonmetallic materials requires additional or modified standards to
maintain the level of safety currently required for metallic materials.
In other cases, the regulatory language may be sufficiently broad to
address nonmetallic materials, but the advisory material may require
updating.
The objective of this notice is to solicit public comments on the
topics that should be addressed, if the FAA proceeds to rulemaking, and
suggestions on the best way to amend part 25 to address the use of
nonmetallic materials as the principal materials of construction.
As noted above, certification standards ideally would not assume
the use of any particular materials, and would contain the standards
necessary to assure the level of safety intended by the regulations
regardless of the materials used. While that is a goal, it may not be
completely achievable, and it is likely that certain assumptions
regarding materials will be necessary for a manageable standard. Still,
the FAA is approaching this effort with the objective of eliminating
assumptions regarding materials as much as is feasible.
Based on our review of current programs, we believe the following
areas would have to be addressed to account for the extensive use of
nonmetallic materials in airframe construction:
Airframe crashworthiness
Fuel Tank crashworthiness
Post crash fire safety
Fuselage protection
Fuel tank protection
In-flight fire safety
Fuselage protection
Fuel tank protection
Lightning protection
Damage tolerance
The FAA seeks public input to further refine the areas of interest
identified above, as well as identify any other relevant areas, in
order to establish the scope of any regulatory efforts and advisory
materials. Based on this input, the FAA may then proceed to rulemaking
activity, or may elect to task the Aviation Rulemaking Advisory
Committee with recommending specific changes to the regulations and
applicable advisory materials.
Issued in Renton, Washington, on April 30, 2009.
Stephen P. Boyd,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E9-12987 Filed 6-3-09; 8:45 am]
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