[Federal Register Volume 71, Number 63 (Monday, April 3, 2006)]
[Proposed Rules]
[Pages 16678-16682]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E6-4791]



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Part V





Department of Transportation





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 Federal Aviation Administration



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14 CFR Part 121



 Fire Penetration Resistance of Thermal Acoustic Insulation Installed 
on Transport Category Airplanes; Proposed Rule

  Federal Register / Vol. 71, No. 63 / Monday, April 3, 2006 / Proposed 
Rules  

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 121

[Docket No.: FAA-2006-24277; Amendment No. 121-323]
RIN 2120-AI75


Fire Penetration Resistance of Thermal Acoustic Insulation 
Installed on Transport Category Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to extend, by 12 months, the date for 
operators to comply with the fire penetration resistance requirements 
of thermal/acoustic insulation used in transport category airplanes 
manufactured after September 2, 2007. This extension is from September 
2, 2007 to September 2, 2008. This action is necessary to allow 
airframe manufacturers enough time, after getting an acceptable 
certification test facility, to select and certificate appropriate 
installations.

DATES: Send your comments by June 2, 2006.

ADDRESSES: You may send comments to Docket No. FAA-2006-24277 using any 
of the following methods:
     DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
     Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility; U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, 
Washington, DC 20590-0001.
     Fax: 1-202-493-2251.
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    For more information on the rulemaking process, see the 
SUPPLEMENTARY INFORMATION section of this document.
    Privacy: We will post all comments we receive, without change, to 
http://dms.dot.gov, including any personal information you provide. For 
more information, see the Privacy Act discussion in the SUPPLEMENTARY 
INFORMATION section of this document.
    Docket: To read background documents or comments received, go to 
http://dms.dot.gov at any time or to Room PL-401 on the plaza level of 
the NASSIF Building, 400 Seventh Street, SW., Washington, DC, between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.

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 98055-
4056; telephone (425) 227-2136, facsimile (425) 227-1149, e-mail: 
[email protected].

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA invites interested persons to take part in this rulemaking 
by sending written comments, data, or views. We also invite comments 
about the economic, environmental, energy, or federalism impacts that 
might result from adopting the proposals in this document. The most 
helpful comments reference a specific portion of the proposal, explain 
the reason for any recommended change, and include supporting data. We 
ask that you send us two copies of written comments.
    We will file in the docket all comments we receive as well as a 
report summarizing each substantive public contact with FAA personnel 
concerning this proposed rulemaking. The docket is available for public 
inspection before and after the comment closing date. If you wish to 
review the docket in person, go to the address in the ADDRESSES section 
of this preamble between 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays. You may also review the docket using the 
Internet at the web address in the ADDRESSES section.
    Privacy Act: Using the search function of our docket web site, 
anyone can find and read the comments received into any of our dockets, 
including the name of the individual sending the comment (or signing 
the comment for an association, business, labor union, or other group). 
You may review DOT's complete Privacy Act Statement in the Federal 
Register published on April 11, 2000 (65 FR 19477-78) or you may visit 
http://dms.dot.gov.
    Before acting on this proposal, we will consider all comments we 
receive by the closing date for comments. We will consider comments 
filed late if it is possible to do so without incurring expense or 
delay. We may change this proposal because of the comments we receive.
    If you want the FAA to acknowledge receipt of your comments on this 
proposal, include with your comments a pre-addressed, stamped postcard 
on which the docket number appears. We will stamp the date on the 
postcard and mail it to you.

Proprietary or Confidential Business Information

    Do not file in the docket any information that you consider to be 
proprietary or confidential business information. Send or deliver this 
information directly to the person identified in the FOR FURTHER 
INFORMATION CONTACT section of this document. You must mark the 
information that you consider proprietary or confidential. If you send 
the information on a disk or CD ROM, mark the outside of the disk or CD 
ROM and identify electronically within the disk or CD ROM the specific 
information that is proprietary or confidential.
    Under 14 CFR 11.35(b), when we are aware of proprietary information 
filed with a comment, we do not place it in the docket. We hold it in a 
separate file to which the public does not have access and place a note 
in the docket that we have received it. If we receive a request to 
examine or copy this information, we treat it as any other request 
under the Freedom of Information Act (5 U.S.C. 552). We process such a 
request under the DOT procedures found in 49 CFR part 7.

Availability of Rulemaking Documents

    You can get an electronic copy using the Internet by:
    (1) Searching the Department of Transportation's electronic Docket 
Management System (DMS) Web page (http://dms.dot.gov/search);
    (2) Visiting the FAA's Regulations and Policies Web page at http://www.faa.gov/regulations_policies/; or
    (3) Accessing the Government Printing Office's Web page at http://www.gpoaccess.gov/fr/index.html.
    You can also get a copy by sending a request to the Federal 
Aviation Administration, Office of Rulemaking, ARM-1, 800 Independence 
Avenue, SW., Washington, DC 20591, or by calling (202) 267-9680. Make 
sure to identify the docket number, notice number, or amendment number 
of this rulemaking.

Authority for This Rulemaking

    The FAA's authority to issue rules regarding aviation safety is 
found in Title 49 of the United States Code. Subtitle I, Section 106 
describes the authority of the FAA Administrator. Subtitle VII, 
Aviation Programs,

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describes in more detail the scope of the agency's authority.
    This rulemaking is promulgated under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701, ``General 
requirements.'' Under that section, the FAA is charged with promoting 
safe flight of civil aircraft in air commerce by prescribing minimum 
standards required in the interest of safety for the design and 
performance of aircraft. This regulation is within the scope of that 
authority, because it prescribes new safety standards for the design of 
transport category airplanes.

Background

    We issued Amendment 121-301 on July 31, 2003, to mandate new 
flammability requirements for thermal/acoustic insulation installed in 
the fuselage of transport category airplanes. This amendment contained 
requirements applicable to newly manufactured airplanes, as well as 
airplanes already in service. The requirements established new 
standards for flame propagation and flame penetration resistance. We 
are proposing to extend the compliance date for the flame penetration 
requirements of the rule applicable to newly manufactured airplanes. 
The compliance date would be extended by 12 months from September 2, 
2007, to September 2, 2008.

Previous Rulemaking

    On September 20, 2000, we published an NPRM to upgrade the 
flammability and fire protection standards for thermal/acoustic 
insulation installed in transport category airplanes. The NPRM 
contained a provision for newly manufactured airplanes entering 14 CFR 
part 121 service to require thermal/acoustic insulation installed in 
the lower half of the fuselage to provide flame penetration resistance 
as required in Sec.  25.856(b). The new test method required by Sec.  
25.856(b) involves the use of an oil burner similar to those used in 
other test methods already required in part 25. The requirement raises 
the level of safety by providing additional time for evacuation in the 
event of a post-crash fire.
    There were many comments on the proposal. Some commenters believed 
it was too stringent, and some commenters stated it was not stringent 
enough. Commenters also discussed the compliance date for newly 
manufactured airplanes, with a similar mixture of those favoring a 
longer compliance date and those suggesting a shorter compliance date. 
Several commenters addressed the cost of this provision and felt it was 
underestimated. Two commenters proposed the objective of the 
requirement, i.e., increasing the time for evacuation, be the basis of 
the requirement rather than the fire safety performance of thermal/
acoustic insulation. We carefully considered all comments received and 
the requirement was adopted in the final rule, published on July 31, 
2003 (68 FR 45046), in new Sec. Sec.  25.856(b) and 121.312(e)(3). 
Section 121.312(e)(3) applies to airplanes manufactured after September 
2, 2007. The goal of the part 121 provision was to raise the level of 
safety of airplanes entering commercial service faster than a new 
airworthiness standard alone would provide.

 Basis of This Proposal

    Following publication of the final rule, and the development of the 
associated Advisory Circular (AC) 25.856-2, we continued to conduct 
comparative testing with industry to refine the test method. During 
this testing, we found that certain elements of the test equipment 
(specifically a fuel nozzle used in the oil burner) were not 
standardized. Although the parts were ostensibly the same, and so 
marked, there were design differences that led to different test 
results at different facilities. The fuel nozzle is used commercially 
in home heating applications where the design differences are not 
significant. However, for the FAA certification test, the differences 
are significant.
    To ensure a standardized configuration, the FAA William J. Hughes 
Technical Center developed a detailed test method and equipment 
configuration. These were based on the procedures and equipment used at 
the Technical Center and were intended to ensure the test method was 
reproducible and repeatable. We recognized the fuel nozzle was an 
important element of the test setup and procured and distributed 
multiple, apparently identical nozzles to other test facilities for 
their use. We conducted comparative tests with multiple test facilities 
through the International Aircraft Materials Fire Test Working Group. 
Based on this work, the test method and equipment was finalized.
    During the development of the test method, materials under 
consideration tended either to provide flame penetration resistance 
that significantly exceeded the requirement, or provide little 
penetration resistance. The materials we evaluated were not just barely 
passing the standard. In retrospect, the lack of such materials tended 
to mask any differences in test facility performance. On deeper 
investigation of the effect of the nozzle on the test results, we 
realized there were potential differences in the flow of air through 
the test burner that could also lead to disparate results from one test 
facility to another. These differences in airflow were likely obscured 
by the material performance and the effects of the fuel nozzle 
originally used. As airframe manufacturers began to develop design 
solutions to comply with the requirement, they developed insulation 
materials and installation methods that were optimized for weight and 
thermal/acoustic performance, while meeting the burnthrough standard. 
The effect of this optimization was to bring the burnthrough 
performance very close to the pass/fail limit of the standard and the 
impact of the nozzle became much greater. Thus, the same insulation 
material could pass the test at the Technical Center but fail at the 
manufacturers' test facilities. This was an unacceptable situation for 
both the FAA and the manufacturers and led to a significant program to 
identify why this was occurring.
    In order to substantiate an installation for approval in accordance 
with Sec.  25.856(b), there are essentially 3 steps required. First, a 
suitable material system needs to be identified and qualified (shown to 
pass the required test). Second, appropriate installation methods must 
be developed and qualified (the materials, when installed using these 
methods, must be shown to pass the test). Finally, the actual design 
data must be generated, once the materials and installation methods 
have been proven. The first two steps are often sequential, since the 
appropriate installation methods may be dictated by the type of 
materials used. However, in some cases, the first two steps could take 
place simultaneously, or essentially so. This is because the FAA has 
identified numerous acceptable installation methods in Advisory 
Circular 25.856-2, and these can be used without further qualification. 
In addition, some installation approaches are not specific to 
particular material types.
    When we issued the final rule, we considered four years sufficient, 
but not generous, to design and implement into production installations 
that meet the fire penetration requirements. Unfortunately, 
identification of the equipment issues consumed a significant portion 
of the 4 year compliance time. While this primarily affected the 
selection of insulation materials, it also had the effect of delaying 
identification of suitable installation methods, and consequently, 
developing specific designs. As

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discussed in the NPRM and final rule implementing the new requirements, 
the installation methodology for thermal/acoustic insulation is 
critical in assuring the flame resistance of the materials actually 
provides a benefit. If the installation does not enable the insulation 
to stay in place in a post-crash fire, the material cannot provide a 
barrier to prevent fire entry into occupied areas.
    Although the rule applies to operators, the practical effect is 
that airframe manufacturers must develop suitable designs. We do not 
expect operators to demonstrate compliance with the fire penetration 
requirements of the final rule independently. Sometimes, the existing 
installation methods are adequate, but for many applications, the 
airframe manufacturer must change the installation approach to 
accommodate the specific materials chosen. Since the thermal/acoustic 
insulation is typically installed in the lower half of the airplane 
very early in the airplane production process, the airframe 
manufacturer must anticipate well in advance which serial production 
airplane must be the first to comply with the requirement. Because the 
test apparatuses have not been fully qualified up to now, the date by 
which changes to designs needed to be incorporated in production has 
passed without the necessary testing completed. This means the current 
compliance date of September 2, 2007, is not achievable unless 
manufacturers use materials that are heavier than we anticipated would 
be necessary, and disrupt production schedules and plans to incorporate 
these materials into current production. The adverse economic impact of 
this effort was not considered during the initial rulemaking.
    While problems with the test equipment have resulted in delays to 
certification and qualification of improved materials and 
installations, the acceptable installation methods identified in AC 
25.856-2 will greatly reduce the need to qualify installations 
separately. Thus, we do not consider the full 4-year compliance time 
cycle should be restarted. While optimized materials are not qualified 
as yet, the FAA is actively working with airframe manufacturers to 
minimize the time required for this step. In most cases, airframe 
manufacturers have identified the primary materials they intend to use, 
assuming certification tests are successful. We have considered the 
ramifications of the delays because of the test equipment and have 
determined that the principal impact is on the detailed design changes. 
Ideally these would have already started. However, considering the 
effect on the schedule of the burner issues, we understand that 
manufacturers are approximately 12 months behind on making design 
changes. Therefore, a 12-month extension from September 2, 2007, would 
enable airframe manufacturers to implement the necessary changes into 
production. By identifying this extension now, the manufacturers can 
plan the necessary design and certification actions and avoid taking 
extraordinary and costly measures to attempt to satisfy the existing 
compliance date.
    This amendment delays an improvement in safety because of 
unforeseen circumstances. This delay in the compliance date means that 
a certain number of additional airplanes will enter the fleet that do 
not meet the flame penetration resistance requirements of Sec.  
25.856(b) later than originally anticipated. There are four airframe 
manufacturers delivering affected airplanes to the United States. We 
expect these manufacturers to implement compliant installations at the 
earliest opportunity, which will likely be before the new compliance 
date. Since the benefits of this provision accumulate as complying 
airplanes enter the fleet, the benefits will be delayed, but will 
ultimately be realized. However, there is no reduction to the current 
safety standard because of this amendment.

Paperwork Reduction Act

    There are no new requirements for information collection associated 
with this amendment.

International Compatibility

    In keeping with U.S. obligations under the Convention on 
International Civil Aviation, it is FAA policy to comply with 
International Civil Aviation Organization (ICAO) Standards and 
Recommended Practices to the maximum extent practicable. The FAA 
determined there are no ICAO Standards and Recommended Practices that 
correspond to these regulations.

Executive Order 12866 and DOT Regulatory Policies and Procedures

    Executive Order 12866, Regulatory Planning and Review, directs the 
FAA to assess both the costs and benefits of a regulatory change. We 
are not allowed to propose or adopt a regulation unless we make a 
reasoned determination that the benefits of the intended regulation 
justify its costs. Our assessment of this proposal indicates that its 
economic impact is minimal. Since its costs and benefits do not make it 
a ``significant regulatory action'' as defined in the Order, we have 
not prepared a ``regulatory impact analysis.'' Similarly, we have not 
prepared a ``regulatory evaluation,'' which is the written cost/benefit 
analysis ordinarily required for all rulemaking proposals under the DOT 
Regulatory and Policies and Procedures. We do not need to do the latter 
analysis where the economic impact of a proposal is minimal.

Economic Assessment, Regulatory Flexibility Determination, 
International Trade Impact Assessment, and Unfunded Mandates Assessment

    Changes to Federal regulations must undergo several economic 
analyses. First, Executive Order 12866 directs that each Federal agency 
shall propose or adopt a regulation only on a reasoned determination 
that the benefits of the intended regulation justify its costs. Second, 
the Regulatory Flexibility Act of 1980 requires agencies to analyze the 
economic impact of regulatory changes on small entities. Third, the 
Trade Agreements Act (19 U.S.C. 2531-2533) prohibits agencies from 
setting standards that create unnecessary obstacles to the foreign 
commerce of the United States. In developing U.S. standards, this Trade 
Act requires agencies to consider international standards and, where 
appropriate, to be the basis of U.S. standards. Fourth, the Unfunded 
Mandates Reform Act of 1995 (Public Law 104-4) requires agencies to 
prepare a written assessment of the costs, benefits, and other effects 
of proposed or final rules that include a Federal mandate likely to 
result in the expenditure by State, local, or tribal governments, in 
the aggregate, or by the private sector, of $100 million or more 
annually (adjusted for inflation). This portion of the preamble 
summarizes the FAA's analysis of the economic impacts of this NPRM.
    The Department of Transportation Order DOT 2100.5 prescribes 
policies and procedures for simplification, analysis, and review of 
regulations. If the expected cost impact is so minimal that a proposal 
does not warrant a full evaluation, this order permits a statement to 
that effect. This statement now follows.
    A one-year postponement of the new thermal acoustic insulation 
standards would spare manufacturers from an additional setup cost of 
slightly more than $50 million at an expected societal loss of $14 
million in benefits. This substantial difference between the cost of 
compliance and expected benefits may run counter to expectations. The 
improved flammability standards for thermal/acoustic insulation 
regulatory

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evaluation (July, 2002) estimated the new insulation requirements will 
produce present value benefits of $222.6 million with present value 
costs of $108.4 million. The benefit/cost delay dichotomy is because of 
substantial setup costs and a relatively short postponement of 
benefits.
    Nearly half of the regulatory evaluation estimated $108 million 
present value costs are the setup costs ($51.1 million in present 
value), which are incurred in the two years before installing the 
improved insulation on new production airplanes. These set-up costs are 
because of configuration management, or the cost resulting from 
engineering time to fully effect changes in airplane configuration--
such as fully accounting for all parts, tools, and shop manual changes. 
To be in compliance with the new requirements the industry would have 
to install different insulation for one year, before lighter weight 
insulation becomes fully available. Two different insulation materials 
require configuration management costs to double.
    With the codification of this proposed rule, society would lose one 
year of additional safety benefits. For that year new production 
airplanes would be produced at today's existing level of fire 
protection, rather than to the improved level of protection. Based on 
the 2002 regulatory evaluation, the one-year loss of benefit equals $14 
million in present value. We estimate the one-year loss in benefit 
based on the 2002 final thermal acoustic regulatory evaluation. In that 
evaluation, the present-value benefits equals $222.6 million. The loss 
of one year of these benefits equals the first year of airplane 
deliveries divided by the total deliveries (476/7702) multiplied by 
$222.6 million, or approximately $14 million.
    The FAA has, therefore, determined this rulemaking action is not a 
``significant regulatory action'' as defined in section 3(f) of 
Executive Order 12866, and is not ``significant'' as defined in DOT's 
Regulatory Policies and Procedures. In addition, the FAA has determined 
that this rulemaking action: (1) Would not have a significant economic 
impact on a substantial number of small entities; (2) would not affect 
international trade; and (3) would not impose an unfunded mandate on 
state, local, or tribal governments, or on the private sector.

Regulatory Flexibility Determination

    The Regulatory Flexibility Act of 1980 (RFA) establishes ``as a 
principle of regulatory issuance that agencies shall endeavor, 
consistent with the objective of the rule and of applicable statutes, 
to fit regulatory and informational requirements to the scale of the 
business, organizations, and governmental jurisdictions subject to 
regulation.'' To achieve that principle, the RFA requires that agencies 
consider flexible regulatory proposals, to explain the rationale for 
their actions, and to solicit comments. The RFA covers a wide-range of 
small entities, including small businesses, not-for-profit 
organizations and small governmental jurisdictions.
    Agencies must perform a review to determine whether a proposed or 
final rule will have a significant economic impact on a substantial 
number of small entities. If the agency determines that it will, the 
agency must prepare a regulatory flexibility analysis as described in 
the RFA.
    However, if an agency determines that a proposed or final rule is 
not expected to have a significant economic impact on a substantial 
number of small entities, section 605(b) of the RFA provides that the 
head of the agency may so certify and a regulatory flexibility analysis 
is not required. The certification must include a statement providing 
additional configuration management cost. While these manufacturers are 
not small entities, the small entity operators are expected to save 
fuel burn expense, as the one-year interim fix insulation is heavier. 
Thus, this rule is cost relieving and does not impose a significant 
economic impact on a substantial number of small entities.
    Consequently, the FAA certifies the rulemaking action would not 
have a significant economic impact on a substantial number of small 
entities. The FAA solicits comments regarding this determination.

International Trade Impact Assessment

    The Trade Agreements Act of 1979 prohibits Federal agencies from 
establishing any standards or engaging in related activities that 
create unnecessary obstacles to the foreign commerce of the United 
States. Legitimate domestic objectives, such as safety, are not 
considered unnecessary obstacles. The statute also requires 
consideration of international standards and, where appropriate, that 
these international standards be the basis for U.S. standards. The FAA 
has assessed the potential effect of this rulemaking action and has 
determined that it provides the same cost relief to domestic and 
international entities and thus has a neutral trade impact.

Unfunded Mandate Assessment

    The Unfunded Mandates Reform Act of 1995 (the Act) is intended, 
among other things, to curb the practice of imposing unfunded Federal 
mandates on State, local, and tribal governments. Title II of the Act 
requires each Federal agency to prepare a written statement assessing 
the effects of any Federal mandate in a proposed or final agency rule 
that may result in an expenditure of $100 million or more (adjusted 
annually for inflation) in any one year by State, local, and tribal 
governments, in the aggregate, or by the private sector. The FAA 
currently uses an inflation-adjusted value of $120.7 million instead of 
$100 million.
    This action does not contain such a mandate. The requirements of 
Title II do not apply.

Executive Order 13132, Federalism

    The FAA has analyzed this proposed rule under the principles and 
criteria of Executive Order 13132, Federalism. We determined that this 
action would not have a substantial direct effect on the States, on the 
relationship between the national Government and the States, or on the 
distribution of power and responsibilities among the various levels of 
government and therefore would not have federalism implications

Regulations Affecting Intrastate Aviation in Alaska

    Section 1205 of the FAA Reauthorization Act of 1996 (119 Sat. 3213) 
requires the Administrator, when modifying regulations in title 14 of 
the CFR in manner affecting intrastate aviation in Alaska, to consider 
the extend to which Alaska is not served by transportation modes other 
than aviation, and to establish such regulatory distinctions as he or 
she considers appropriate. Because this proposed rule would apply to 
the certification of newly manufactured transport category airplanes 
and their subsequent operation, it could, if adopted, affect intrastate 
aviation in Alaska. The FAA therefore specifically requests comments on 
whether there is justification of applying the proposed rule 
differently in intrastate operations in Alaska.

Environmental Analysis

    Federal Aviation Administration Order 1050.1E identifies FAA 
actions that are categorically excluded from preparation of an 
environmental assessment or environmental impact statement under the 
National Environmental Policy Act without extraordinary circumstances. 
The FAA has determined this proposed

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rulemaking action qualifies for the categorical exclusion identified in 
paragraph 3f and involves no extraordinary circumstances.

Regulations That Significantly Affect Energy Supply, Distribution, or 
Use

    The FAA has analyzed this proposed rulemaking under Executive Order 
13211, Actions Concerning Regulations That Significantly Affect Energy 
Supply, Distribution, or Use (66 FR 28355, May 18, 2001). We have 
determined that it is not a ``significant energy action'' under the 
executive order because it is not a ``significant regulatory action'' 
under Executive Order 12866, and it is not likely to have a significant 
adverse effect on the supply, distribution, or use of energy.

Lists of Subjects

14 CFR Part 121

    Aircraft, Aviation safety.

The Proposed Amendment

    In consideration of the foregoing, the Federal Aviation 
Administration proposes to amend part 121 of Title 14, Code of Federal 
Regulations, as follows:

PART 121--OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL 
OPERATIONS

    1. The authority citation for part 121 continues to read as 
follows:

    Authority: 49 U.S.C. 106(g), 40113, 40119, 44101, 44701-44702, 
44705, 44709-44711, 44713, 44716-44717, 44722, 44901, 44903-44904, 
44912, 46105.

    2. Amend Sec.  121.312 by revising paragraph (e)(3) to read as 
follows:


Sec.  121.312  Materials for compartment interiors.

* * * * *
    (e) Thermal/acoustic insulation materials. For transport category 
airplanes type certificated after January 1, 1958:
* * * * *
    (3) For airplanes with a passenger capacity of 20 or greater, 
manufactured after September 2, 2008, thermal/acoustic insulation 
materials installed in the lower half of the fuselage must meet the 
flame penetration resistance requirements of Sec.  25.856 of this 
chapter, effective September 2, 2003.

    Issued in Washington, DC, on March 27, 2006.
Dorenda D. Baker,
Acting Director, Aircraft Certification Service.
 [FR Doc. E6-4791 Filed 3-31-06; 8:45 am]
BILLING CODE 4910-13-P