[Federal Register Volume 67, Number 19 (Tuesday, January 29, 2002)]
[Proposed Rules]
[Pages 4318-4322]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-1767]



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Part II





Department of Transportation





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Federal Aviation Administration



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14 CFR Part 25



Revised Requirement for Material Strength Properties and Design Values 
for Transport Airplanes and Notice of Proposed Advisory Circular (AC) 
25.613-1X; Proposed Rule and Notice

  Federal Register / Vol. 67 , No. 19 / Tuesday, January 29, 2002 / 
Proposed Rules  

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2002-11345; Notice No. 02-05]
RIN 2120-AH36


Revised Requirement for Material Strength Properties and Design 
Values for Transport Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The Federal Aviation Administration proposes to revise the 
material strength properties and material design values requirement for 
transport category airplanes by incorporating changes developed in 
cooperation with the Joint Aviation Authorities of Europe and the U.S. 
and European aviation industry through the Aviation Rulemaking Advisory 
Committee (ARAC). This action is necessary because differences between 
the current U.S. and European requirements impose unnecessary costs on 
airplane manufacturers. These proposals are intended to achieve common 
requirements and language between the requirements of the U.S. 
regulations and the Joint Aviation Requirements (JAR) of Europe, while 
maintaining at least the level of safety provided by the current 
regulations and industry practice.

DATES: Send your comments on or before April 1, 2002.

ADDRESSES: Address your comments to the Docket Management System, U.S. 
Department of Transportation, Room Plaza 401, 400 Seventh Street SW., 
Washington, DC 20590-0001. You must identify the docket number, FAA-
2002-11345 at the beginning of your comments, and you should submit two 
copies of your comments. If you wish to receive confirmation that the 
FAA has received your comments, please include a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket No. FAA-2002-XXXX.'' We will date-stamp the postcard and mail 
it back to you.
    You also may submit comments electronically to the following 
Internet address: http://dms.dot.gov. You may review the public docket 
containing comments to these proposed regulations in person in the 
Dockets Office between 9:00 a.m. and 5:00 p.m., Monday through Friday, 
except Federal holidays. The Dockets Office is on the plaza level of 
the NASSIF Building at the Department of Transportation at the above 
address. Also, you may review public dockets on the Internet at http://dms.dot.gov.

FOR FURTHER INFORMATION CONTACT: Rich Yarges, Airframe/Cabin Safety 
Branch, ANM-115, FAA Transport Airplane Directorate, Aircraft 
Certification Service, 1601 Lind Avenue, SW., Renton, WA 98055-4056; 
telephone (425) 227-2143, facsimile (425) 227-1320, e-mail 
[email protected].

SUPPLEMENTARY INFORMATION:

How Do I Submit Comments to This NPRM?

    Interested persons are invited to participate in the making of the 
proposed action by submitting such written data, views, or arguments as 
they may desire. Comments relating to the environmental, energy, 
federalism, or economic impact that might result from adopting the 
proposals in this document also are invited. Substantive comments 
should be accompanied by cost estimates. Comments must identify the 
regulatory docket or notice number and be submitted in duplicate to the 
DOT Rules Docket address specified above.
    All comments received, as well as a report summarizing each 
substantive public contact with FAA personnel concerning this proposed 
rulemaking, will be filed in the docket. The docket is available for 
public inspection before and after the comment closing date.
    We will consider all comments received on or before the closing 
date before taking action on this proposed rulemaking. Comments filed 
late will be considered as far as possible without incurring expense or 
delay. The proposals in this document may be changed in light of the 
comments received.

How Can I Obtain a Copy of This NPRM?

    You can get an electronic copy using the Internet by taking the 
following steps:
    (1) Go to the search function of the Department of Transportation's 
electronic Docket Management System (DMS) web page (http://dms.dot.gov/search).
    (2) On the search page type in the last four digits of the Docket 
number shown at the beginning of this notice. Click on ``search.''
    (3) On the next page, which contains the Docket summary information 
for the Docket you selected, click on the document number of the item 
you wish to view.
    You can also get an electronic copy using the Internet through the 
Office of Rulemaking's web page at http://www.faa.gov/avr/armhome.htm 
or the Government Printing Office's web page at http://www.access.gpo.gov/su_docs/aces/aces140.html.
    You can also get a copy by submitting 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.

What Are the Relevant Airworthiness Standards in the United States?

    In the United States, the airworthiness standards for type 
certification of transport category airplanes are contained in Title 
14, Code of Federal Regulations (CFR) part 25. Manufacturers of 
transport category airplanes must show that each airplane they produce 
of a different type design complies with the appropriate part 25 
standards. These standards apply to:
     Airplanes manufactured within the U.S. for use by U.S.-
registered operators, and
     Airplanes manufactured in other countries and imported to 
the U.S. under a bilateral airworthiness agreement.

What Are the Relevant Airworthiness Standards in Europe?

    In Europe, the airworthiness standards for type certification of 
transport category airplanes are contained in Joint Aviation 
Requirements (JAR)-25, which are based on part 25. These were developed 
by the Joint Aviation Authorities (JAA) of Europe to provide a common 
set of airworthiness standards within the European aviation community. 
Twenty-three European countries accept airplanes type certificated to 
the JAR-25 standards, including airplanes manufactured in the U.S. that 
are type certificated to JAR-25 standards for export to Europe.

What Is ``Harmonization'' and How Did It Start?

    Although part 25 and JAR-25 are very similar, they are not 
identical in every respect. When airplanes are type certificated to 
both sets of standards, the differences between part 25 and JAR-25 can 
result in substantial additional costs to manufacturers and operators. 
These additional costs, however, frequently do not bring about an 
increase in safety. In many cases, part 25 and JAR-25 may contain 
different requirements to accomplish the same safety intent.

[[Page 4319]]

Consequently, manufacturers are usually burdened with meeting the 
requirements of both sets of standards, although the level of safety is 
not increased correspondingly.
    Recognizing that a common set of standards would not only benefit 
the aviation industry economically, but also maintain the necessary 
high level of safety, the FAA and the JAA began an effort in 1988 to 
``harmonize'' their respective aviation standards. The goal of the 
harmonization effort is to ensure that:
     Where possible, standards do not require domestic and 
foreign parties to manufacture or operate to different standards for 
each country involved; and
     The standards adopted are mutually acceptable to the FAA 
and the foreign aviation authorities.
    The FAA and JAA have identified a number of significant regulatory 
differences (SRD) between the wording of part 25 and JAR-25. Both the 
FAA and the JAA consider ``harmonization'' of the two sets of standards 
a high priority.

What Is ARAC and What Role Does It Play in Harmonization?

    After initiating the first steps towards harmonization, the FAA and 
JAA soon realized that traditional methods of rulemaking and 
accommodating different administrative procedures was neither 
sufficient nor adequate to make appreciable progress towards fulfilling 
the goal of harmonization. The FAA then identified the Aviation 
Rulemaking Advisory Committee (ARAC) as an ideal vehicle for assisting 
in resolving harmonization issues, and, in 1992, the FAA tasked ARAC to 
undertake the entire harmonization effort.
    The FAA had formally established ARAC in 1991 (56 FR 2190, January 
22, 1991), to provide advice and recommendations concerning the full 
range of the FAA's safety-related rulemaking activity. The FAA sought 
this advice to develop better rules in less overall time and using 
fewer FAA resources than previously needed. The committee provides the 
FAA firsthand information and insight from interested parties regarding 
potential new rules or revisions of existing rules.
    There are 64 member organizations on the committee, representing a 
wide range of interests within the aviation community. Meetings of the 
committee are open to the public, except as authorized by section 10(d) 
of the Federal Advisory Committee Act.
    The ARAC establishes working groups to develop recommendations for 
resolving specific airworthiness issues. Tasks assigned to working 
groups are published in the Federal Register. Although working group 
meetings are not generally open to the public, the FAA solicits 
participation in working groups from interested members of the public 
who possess knowledge or experience in the task areas. Working groups 
report directly to the ARAC, and the ARAC must accept a working group 
proposal before ARAC presents the proposal to the FAA as an advisory 
committee recommendation.
    The activities of the ARAC will not, however, circumvent the public 
rulemaking procedures; nor is the FAA limited to the rule language 
``recommended'' by ARAC. If the FAA accepts an ARAC recommendation, the 
agency proceeds with the normal public rulemaking procedures. Any ARAC 
participation in a rulemaking package is fully disclosed in the public 
docket.

What Is the Status of the Harmonization Effort Today?

    Despite the work that ARAC has undertaken to address harmonization, 
there remain a large number of regulatory differences between part 25 
and JAR-25. The current harmonization process is extremely costly and 
time-consuming for industry, the FAA, and the JAA. Industry has 
expressed a strong desire to conclude the harmonization program as 
quickly as possible to alleviate the drain on their resources and to 
finally establish one acceptable set of standards.
    Recently, representatives of the aviation industry [including 
Aerospace Industries Association of America, Inc. (AIA), General 
Aviation Manufacturers Association (GAMA), and European Association of 
Aerospace Industries (AECMA)] proposed an accelerated process to reach 
harmonization.

What Is the ``Fast Track Harmonization Program''?

    In light of a general agreement among the affected industries and 
authorities to expedite the harmonization program, the FAA and JAA in 
March 1999 agreed upon a method to achieve these goals. This method, 
which the FAA has titled ``The Fast Track Harmonization Program,'' is 
aimed at expediting the rulemaking process for harmonizing not only the 
42 standards that are currently tasked to ARAC for harmonization, but 
approximately 80 additional standards for part 25 airplanes.
    The FAA initiated the Fast Track program on November 26, 1999 (64 
FR 66522). This program involves grouping all of the standards needing 
harmonization into three categories:
    Category 1: Envelope--For these standards, parallel part 25 and 
JAR-25 standards would be compared, and harmonization would be reached 
by accepting the more stringent of the two standards. Thus, the more 
stringent requirement of one standard would be ``enveloped'' into the 
other standard. In some cases, it may be necessary to incorporate parts 
of both the part 25 and JAR standard to achieve the final, more 
stringent standard. (This may necessitate that each authority revises 
its current standard to incorporate more stringent provisions of the 
other.)
    Category 2: Completed or near complete--For these standards, ARAC 
has reached, or has nearly reached, technical agreement or consensus on 
the new wording of the proposed harmonized standards.
    Category 3: Harmonize--For these standards, ARAC is not near 
technical agreement on harmonization, and the parallel part 25 and JAR-
25 standards cannot be ``enveloped'' (as described under Category 1) 
for reasons of safety or unacceptability. A standard developed under 
Category 3 would be mutually acceptable to the FAA and JAA, with a 
consistent means of compliance.
    Further details on the Fast Track Program can be found in the 
tasking statement (64 FR 66522, November 26, 1999) and the first NPRM 
published under this program, Fire Protection Requirements for 
Powerplant Installations on Transport Category Airplanes (65 FR 36978, 
June 12, 2000).
    By notice in the Federal Register (60 FR 4222, January 20, 1995), 
the FAA tasked an ARAC working group of industry and government 
structural specialists from Europe, the United States, and Canada to 
review Sec. 25.613 of part 25, along with corresponding paragraph 
25.613 of the JAR, and supporting policy and guidance material, and to 
recommend to the FAA appropriate revisions for harmonization, including 
advisory material. The ARAC working group completed its work on that 
task and submitted its recommendation to the FAA. That effort was then 
absorbed under the Fast Track program when it was established in 1999. 
The regulatory changes proposed in this notice result from the 
recommendation of ARAC.

Discussion of the Proposal

    Section 25.613 of part 25 prescribes requirements for material 
static strength properties and design values. Metallic material 
strength properties for aircraft manufactured in the U.S. have 
traditionally been based on those specified in Military Handbook (MIL-

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HDBK)-5. For metallic materials not listed in that handbook, the 
statistical procedures in the handbook were normally used to determine 
material strength properties. Prior to Amendment 25-72 to part 25 (55 
FR 29786, July 20, 1990), the ``A'' or ``B'' material strength 
properties listed in MIL-HDBK-5, or those listed in MIL-HDBK-17, and -
23, or Army-Navy-Commerce (ANC)-18, were required to be used unless 
specific FAA approval was granted to use other properties. With 
Amendment 25-72, Secs. 25.613 and 25.615 were combined into one 
requirement, Sec. 25.613, and the references to MIL-HDBK-5, -17, -23, 
and ANC-18 were removed. As part of that amendment, the requirement to 
use ``A'' and ``B'' properties of the military handbook was replaced by 
a more general requirement specifying probabilities and confidence 
levels for material strength properties, with the test procedures and 
statistical methods unspecified. Those probability and confidence 
levels apply to metallic as well as non-metallic materials. In Europe, 
other standards have been used in showing compliance with JAR 25.613, 
such as the Euronorm, International Standard Organization, and 
Engineering Sciences Data Unit 00932 Metallic Data Handbook.
    Because Amendment 25-72 removed the provision which permitted the 
Administrator to approve ``other design values,'' such an approval 
requires an equivalent safety finding. This finding results in 
additional administrative time for both the manufacturer and the FAA. 
To reduce this administrative burden, the FAA proposes to revise the 
rule to reinstate the pre-amendment 25-72 provision. In addition, other 
changes of a clarifying nature are proposed.

Proposed Changes

    This proposal would revise Sec. 25.613 as follows:
     The heading of Sec. 25.613 would be revised to read, 
``Material Strength Properties and Material Design Values.'' This 
change would clarify that the design values are material design values.
     Paragraph (a) would remain unchanged.
     Paragraph (b) would be revised to clarify that the design 
values are material design values. The ``A'' and ``B'' properties 
published in MIL-HDBK-5 and -17, or in equivalent handbooks, would be 
acceptable without further statistical analysis. The statistical 
methods specified in MIL-HDBK-5 and -17 would be acceptable for use in 
establishing material design values. Other statistical methods, amounts 
of data, and material property data might also be acceptable, including 
those specified in the European Standards previously noted.
     Paragraph (c) currently requires consideration of the 
effects of temperature on allowable stresses used for design where 
thermal effects are significant under normal operating conditions. The 
proposed revision would require consideration of environmental 
conditions in general, such as temperature and moisture, on material 
design values used in an essential component or structure, where those 
effects are significant in the airplane operating envelope. This change 
is made because environmental factors other than temperature may have a 
significant effect on allowable stresses, not only under normal 
operating conditions, but also at other conditions within the airplane 
operating envelope.
     Paragraph (d) would be removed by this proposal as fatigue 
is now adequately addressed in Sec. 25.571.
     The premium selection process of paragraph (e) would be 
revised to clarify that the design values are material design values.
     A new paragraph (f) is proposed, which would permit the 
use of other design values if they are approved by the Administrator.
    A draft Advisory Circular, AC 25.613-1X, Material Strength 
Properties and Material Design Values, which describes acceptable 
methods of compliance with this proposed rule, is being developed 
concurrently with this proposal. Public comments concerning the 
proposed AC are invited by separate notice published elsewhere in this 
issue of the Federal Register.

Paperwork Reduction Act

    In accordance with the Paperwork Reduction Act of 1995 (44 U.S.C. 
3507(d)), the FAA has determined that there are no requirements for 
information collection associated with this proposed rule.

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 has 
determined that there are no ICAO Standards and Recommended Practices 
that correspond to these proposed regulations.

Regulatory Evaluation Summary

    Proposed changes to Federal regulations must undergo several 
economic analyses. First, Executive Order 12866 directs each Federal 
agency to propose or adopt a regulation only if the agency makes 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. section 
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. Where appropriate, agencies are directed to 
use those international standards as the basis of U.S. standards. And 
fourth, the Unfunded Mandates Reform Act of 1995 requires agencies to 
prepare a written assessment of the costs, benefits, and other effects 
of proposed or final rules. This requirement applies only to rules that 
include a Federal mandate on State, local, or tribal governments or the 
private sector, likely to result in a total expenditure of $100 million 
or more in any one year (adjusted for inflation.)
    In conducting these analyses, the FAA has determined this proposed 
rule: (1) Has benefits which do justify its costs, is not a 
``significant regulatory action'' as defined in the Executive Order, 
and is not ``significant'' as defined in DOT's Regulatory Policies and 
Procedures; (2) would not have a significant impact on a substantial 
number of small entities; (3) would not have an negative impact on 
international trade; and (4) would not impose an unfunded mandate on 
state, local, or tribal governments, or on the private sector. The FAA 
has placed these analyses in the docket and summarized them below.
    The proposed rule would incorporate changes developed in 
cooperation with the Joint Aviation Authorities (JAA) of Europe and the 
U.S. and European aviation industry through the Aviation Rulemaking 
Advisory Committee (ARAC). If adopted, the proposed amendment would 
revise the requirements for material strength properties and material 
design values for transport category airplanes. Furthermore, the 
proposal would harmonize FAA requirements with those proposed by the 
JAA.
    There would be no incremental costs as a result of the proposed 
rule. Rather, the proposed rule would result in cost savings to 
manufacturers and the FAA by reinstating a provision that permits the 
Administrator to approve other material design values published in 
accepted military and industry handbooks. A draft Advisory Circular

[[Page 4321]]

(AC) accompanies this proposed rule and describes the acceptable 
methods of compliance. As a result, in certain material design values 
cases, the FAA estimates that the proposed rule would result in cost 
savings to manufacturers of transport category airplanes of at least 
$100,000 per initial aircraft certification. In addition, the FAA would 
realize an estimated administrative cost saving of approximately $1,460 
per certification. Finally, by harmonizing JAA and FAA requirements, 
the proposed rule would create a single set of requirements accepted in 
both the United States and Europe. This action would foster 
international trade and make the aircraft certification process more 
efficient. Accordingly, the FAA has determined that the proposed rule 
would be cost-beneficial. The FAA solicits comments from affected 
entities with respect to this finding and determination and requests 
that all comments be accompanied by clear documentation.

Initial 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 Act requires agencies to 
solicit and consider flexible regulatory proposals and to explain the 
rationale for their actions. The Act 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 determination is that it will, the 
agency must prepare a regulatory flexibility analysis as described in 
the Act.
    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 1980 act 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 the factual basis for this determination, and the reasoning 
should be clear.
    This proposed rule would affect manufacturers of transport category 
airplanes. However, all United States transport-aircraft category 
manufacturers exceed the Small Business Administration (SBA) small-
entity standard of 1,500 employees for aircraft manufacturers. United 
States part 25 airplane manufacturers include: Boeing, Cessna Aircraft, 
Gulfstream Aerospace, Learjet (owned by Bombardier), Lockheed Martin, 
McDonnell Douglas (a wholly-owned subsidiary of The Boeing Company), 
Raytheon Aircraft, and Sabreliner Corporation. Consequently, the 
Federal Aviation Administration certifies that the proposed rule would 
not have a significant economic impact on a substantial number of small 
entities. The FAA solicits comments from affected entities with respect 
to this finding and determination and requests that all comments be 
accompanied by clear documentation.

International Trade Impact Assessment

    The Trade Agreement Act of 1979 prohibits Federal agencies from 
engaging in any standards or 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 they be the basis for U.S. 
standards. In accordance with the above statute, the FAA has assessed 
the potential effect of this proposed rule and has determined that it 
complies with the Act because this rule would use European 
international standards as the basis for U.S. standards.

Unfunded Mandates Assessment

    The Unfunded Mandates Reform Act of 1995 (the Act), enacted as 
Public Law 104-4 on March 22, 1995, 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 a $100 million or more 
expenditure (adjusted annually for inflation) in any one year by State, 
local, and tribal governments, in the aggregate, or by the private 
sector; such a mandate is deemed to be a ``significant regulatory 
action.''
    This proposed rule does not contain such a mandate. Therefore, the 
requirements of Title II of the Unfunded Mandates Reform Act of 1995 do 
not apply.

Executive Order 13132, Federalism

    The FAA has analyzed this proposed rule and the principles and 
criteria of Executive Order 13132, Federalism. The FAA has 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. Therefore, the FAA has determined that 
this notice of proposed rulemaking would not have federalism 
implications.

Environmental Analysis

    FAA Order 1050.1D defines FAA actions that may be categorically 
excluded from preparation of a National Environmental Policy Act (NEPA) 
environmental assessment or environmental impact statement. In 
accordance with FAA Order 1050.1D, appendix 4, paragraph 4(j), this 
proposed rulemaking action qualifies for a categorical exclusion.

Energy Impact

    The energy impact of the proposed rule has been assessed in 
accordance with the Energy, Policy, and Conservation Act (EPCA), Public 
Law 94-163, as amended (43 U.S.C. 6362), and FAA Order 1053.1. It has 
been determined that the proposed rule is not a major regulatory action 
under the provisions of the EPCA.

Regulations Affecting Interstate Aviation in Alaska

    Section 1205 of the FAA Reauthorization Act of 1996 (110 Stat. 
3213) requires the Administrator, when modifying regulations in title 
14 of the CFR in a manner affecting interstate aviation in Alaska, to 
consider the extent 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 future designs of transport 
category airplanes and their subsequent operation, it could, if 
adopted, affect interstate aviation in Alaska. The FAA therefore 
specifically requests comments on whether there is justification for 
applying the proposed rule differently in interstate operations in 
Alaska.

List of Subjects in 14 CFR Part 25

    Aircraft, Aviation safety, Reporting and recordkeeping 
requirements.

The Proposed Amendment

    In consideration of the foregoing, the Federal Aviation 
Administration proposes to amend part 25 of Title 14, Code of Federal 
Regulations, as follows:

[[Page 4322]]

PART 25--AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES

    1. The authority citation for part 25 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701-44702, and 44704.
    2. Amend Sec. 25.613 by revising the section heading and paragraphs 
(b) introductory text, (c), and (e); by removing and reserving 
paragraph (d); and by adding a new paragraph (f) to read as follows:


Sec. 25.613  Material strength properties and material design values

* * * * *
    (b) Material design values must be chosen to minimize the 
probability of structural failures due to material variability. Except 
as provided in paragraphs (e) and (f) of this section, compliance must 
be shown by selecting material design values which assure material 
strength with the following probability:
* * * * *
    (c) The effects of environmental conditions, such as temperature 
and moisture, on material design values used in an essential component 
or structure must be considered where these effects are significant 
within the airplane operating envelope.
    (d) [Reserved]
    (e) Greater material design values may be used if a `` premium 
selection `` of the material is made in which a specimen of each 
individual item is tested before use to determine that the actual 
strength properties of that particular item will equal or exceed those 
used in design.
    (f) Other material design values may be used if approved by the 
Administrator.

    Issued in Renton, Washington, on January 8, 2002.
Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 02-1767 Filed 1-28-02; 8:45 am]
BILLING CODE 4910-13-P