[Federal Register Volume 74, Number 106 (Thursday, June 4, 2009)]
[Notices]
[Pages 26919-26920]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E9-12987]


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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:
    <bullet> Airframe crashworthiness
    <bullet> Fuel Tank crashworthiness
    <bullet> Post crash fire safety
     <bullet> Fuselage protection
     <bullet> Fuel tank protection
    <bullet> In-flight fire safety
     <bullet> Fuselage protection
     <bullet> Fuel tank protection
    <bullet> Lightning protection
    <bullet> 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]
BILLING CODE 4910-13-P