[Federal Register Volume 66, Number 95 (Wednesday, May 16, 2001)]
[Rules and Regulations]
[Pages 27390-27394]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-12231]



[[Page 27389]]

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Part IV





Department of Transportation





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Federal Aviation Administration



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14 CFR Part 25



Revised Landing Gear Shock Absorption Test Requirements; Final Rule

  Federal Register / Vol. 66, No. 95 / Wednesday, May 16, 2001 / Rules 
and Regulations  

[[Page 27390]]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-1999-5835; Amendment No. 25-103]
RIN 2120-AG72


Revised Landing Gear Shock Absorption Test Requirements

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: This amendment revises the airworthiness standards for landing 
gear shock absorption test requirements for transport category 
airplanes by incorporating 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). This amendment reduces the number of design weight conditions 
required to be demonstrated by shock absorption tests and changes the 
objective of the tests to include the complete validation of the 
landing gear dynamic characteristics. This amendment also removes some 
means of compliance criteria from the rule since it is more 
appropriately set forth in advisory material.

EFFECTIVE DATE: June 15, 2001.

FOR FURTHER INFORMATION CONTACT: James Haynes, Airframe and Cabin 
Safety Branch, ANM-115, Transport Airplane Directorate, Aircraft 
Certification Service, FAA, 1601 Lind Ave. SW., Renton, WA 98055-4056; 
telephone (425) 227-2131.

SUPPLEMENTARY INFORMATION:

Availability of Final Rules

    You can get and 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 amendment. Click on ``search.''
    (3) On the next page, which contains the Docket summary information 
for the Docket you selected, click on the final rule.
    You can also get and electronic copy using the Internet through 
FAA's web page at http://www.faa.gov/avr/arm/nprm/nprm.htm or the 
Federal Register's web page at http://www.access.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 amendment number or docket number of this final 
rule.

Small Business Regulatory Enforcement Fairness Act

    The Small Business Regulatory Enforcement Fairness Act (SBREFA) of 
1996, requires the FAA to comply with small entity requests for 
information or advice about compliance with statutes and regulations 
within its jurisdiction. Therefore, any small entity that has a 
question regarding this document may contact their local FAA official, 
or the person listed under FOR FURTHER INFORMATION CONTACT. You can 
find out more about SBREFA on the Internet at our site http://www.faa.gov/avr/arm/sbrefa.htm For more information on SBREFA, e-mail 
us at [email protected].

Background

    The manufacturing, marketing and certification of transport 
airplanes is increasingly an international endeavor. In order for 
United States manufacturers to export transport airplanes to other 
countries, the airplane must be designed to comply, not only with the 
U.S. airworthiness requirements for transport airplanes (14 CFR part 
25), but also with the transport airworthiness requirements of the 
countries to which the airplane is to be exported.
    The European countries have developed a common airworthiness code 
for transport airplanes that is administered by the JAA of Europe. This 
code is the result of a European effort to harmonize the various 
airworthiness codes of the European countries and is called the Joint 
Aviation Requirements (JAR)-25. It was developed in a format similar to 
part 25. Many other countries have airworthiness codes that are aligned 
closely to part 25 or to JAR-25, or they use these codes directly for 
their own certification purposes.
    The ARAC was established by the FAA on February 15, 1991, with the 
purpose of providing information, advice, and recommendations to be 
considered in rulemaking activities. By notice in the Federal Register 
(59 FR 30081, June 10, 1994), the FAA assigned several new tasks to an 
ARAC working group of industry and government structural loads 
specialists from Europe, the United States, and Canada. Task 6 of the 
working group charter concerned the shock absorption test requirements 
for landing gear. The ARAC working group completed its work for this 
task and the ARAC made recommendations to the FAA by letter dated 
October 29, 1997.
    Although the requirements for landing gear shock absorption tests 
are essentially the same between the Federal Aviation Regulations (FAR) 
and JAR, the requirements do not address the capabilities of modern 
technology and do not take into account other related changes in the 
requirements for landing gear load conditions that have already been 
incorporated into other sections of the FAR. When the landing loads 
requirements for transport airplanes were originally developed, the 
required the landing load factors to be determined and applied to the 
airplane. The airplane was treated as a rigid body and the landing 
loads were applied to this rigid representation of the airplane for the 
purpose of structural analysis. For the early landing gear systems, 
analysis alone was considered sufficient for determining the landing 
load factor that will be applied to the rigid airplane. It was only 
necessary to determine the landing load factor (by analysis or tests) 
and this load factor will then be used to design and substantiate the 
airplane for the landing load conditions.
    The development of more complex landing gear systems, for which 
analysis alone was unreliable, led to the adoption of a requirement to 
verify the landing factor by actual shock absorption tests. This 
requirement was added to the Civil Air Regulations (CAR) 4b, which was 
the predecessor to part 25. These shock absorption tests were allowed 
by Sec. 4b.200 of the CAR to be free drop tests in which the gear 
alone, could be dropped in free fall to impact the ground. In these 
tests, mass is added to represent the proportion of the airplane weight 
on the landing gear unit, and the mass may be reduced to account for 
the effects of airplane lift acting during the landing impact. Later, 
the corresponding requirement in Sec. 25.723(a), was modified to allow 
the substantiation of some changes to the landing gear shock absorption 
systems by analysis alone without verification by tests.
    Prior to this amendment, Secs. 25.473(d) and 25.723(a) for shock 
absorption tests required just the determination of the limit landing 
load factor from the shock absorption test. However, the landing gear 
shock absorption systems had become even more sophisticated and the 
airplane had become more flexible. Part 25 was previously revised to 
require that determinations of airplane loads in the landing 
configuration take into

[[Page 27391]]

account the dynamic flexibility of the airplane. In order to determine 
the airplane loads in the landing load conditions, it was no longer 
sufficient to determine just the load factor from a drop test of a 
landing gear unit. A comprehensive analysis of the combined dynamic 
systems for the landing gear and airplane had become essential in order 
to determine the structural design loads for the airplane. In 
developing the mathematical model, it is necessary to provide an 
accurate representation of all the landing gear dynamic 
characteristics. This includes the energy absorption characteristics 
and the time histories of force and displacement during a landing 
impact.
    Notice 99-08 was published in the Federal Register on June 18, 1999 
(64 FR 32978). The notice proposes to revise the main objective of the 
shock absorption tests to be the validation of the landing gear dynamic 
characteristics which make up the analytical model rather than just to 
determine the landing load factors. In addition, the number of actual 
design weight conditions were proposed to be reduced to include just 
the landing weight, or design take-off weight, whichever provided the 
greatest landing impact energy. Furthermore, Secs. 25.725 and 25.727 
were proposed to be removed from part 25, since these sections only 
contained criteria for one means of compliance to the shock absorption 
test requirement. These criteria were proposed to be set forth as 
acceptable means of compliance in Advisory Circular (AC) 25.723-1 
``Shock Absorption Tests.''

Discussion of Comments

    There are 6 commenters from aviation manufacturers and foreign 
airworthiness authorities. Although one commenter objects to the 
proposed rule, most of the commenters support the proposed changes. 
Several of the commenters provide suggestions for clarity, consistency 
and organization. Comments are summarized as follows along with 
disposition.
    One commenter objects to the proposed change in the basic purpose 
of the shock absorption tests from the validation of the load factors 
to the validation of the dynamic characteristics of the landing gear. 
The commenter believes that the new proposal has the potential for 
requiring a significant volume of recalculation for refinement of load 
values and this would be neither productive nor cost effective. 
Furthermore, the commenter believes that this approach would not fit 
well in the timeline between design concept and the development of the 
first prototype and so would bring the potential for discovering a 
different answer for the completed product late in the design process. 
Finally, the commenter believes the existing regulations are 
sufficient. The FAA agrees that validation of dynamic characteristics 
by test always brings a risk if the assumptions made in the prediction 
of these characteristics are not sufficiently accurate or conservative. 
However, the process of prediction, design, and validation are normal, 
and expected, in the development of aircraft and the risks can be 
minimized by the use of conservative assumptions. Furthermore, the FAA 
does not agree that the existing shock absorption test requirements are 
sufficient. The development of airplane loads for dynamic landing 
conditions requires a valid analytical model of the landing gear which 
includes a valid representation of the energy absorbing characteristics 
of the gear. The dynamic landing requirement has existed in 14 CFR part 
25 for a number of years but the validation shock absorption test 
requirement has remained outdated, since it requires only the 
validation of a simple static landing load factor which may not even be 
used in design of the airplane. Because of the existing dynamic landing 
requirement, it has become a standard practice to develop the design 
loads for the airplane structure based on a mathematical model of the 
airplane and landing gear and to validate the assumed gear 
characteristics by shock absorption tests. Therefore, the requirement 
is being updated to be consistent with the related design landing load 
requirements and also to be consistent with standard practice.
    One commenter points out that the terminology used in the proposed 
Sec. 25.723(a)(1) for design weight conditions was inconsistent with 
that used in Sec. 25.473, ``Landing load conditions and assumptions,'' 
which is the same as that used in the proposed AC 25.723-1. The FAA 
agrees, and the language in the new Sec. 25.723(a)(1) has been changed 
to refer to these design weight conditions as ``limit design 
conditions'' and to use the terms ``design landing weight'' and 
``design takeoff weight'' to be consistent with Sec. 25.473(a).
    One commenter is concerned that the proposed location of the 
requirement for shock absorption tests in Sec. 25.473(d) implies that 
the individual tests would be required for each of the landing 
conditions and configurations specified in Sec. 25.473, including 
unsymmetrical conditions. The FAA does not agree since the specific 
landing conditions are referenced in Sec. 25.473(a) while the 
requirement related to validating landing gear dynamic characteristics, 
potentially of use in some or all conditions, is set forth in 
Sec. 25.473(d). Validation is intended to mean that the adequacy of the 
dynamic characteristics would be confirmed by shock absorption tests to 
whatever extent necessary to provide confidence in the analysis of the 
specified landing conditions. To clarify this intent, an additional 
sentence is added to Sec. 25.723(a) which would require that a range of 
tests be conducted to ensure that the analytical representation is 
valid for the design condition specified in Sec. 25.723.
    The same commenter suggests that the terms, ``dynamic 
characteristics,'' are ambiguous and that the rule should completely 
define dynamic characteristics and specify which dynamic 
characteristics must be validated by tests. The FAA agrees that these 
terms are general. However, the FAA does not agree that an exhaustive 
list of dynamic characteristics or shock absorption characteristics can 
be provided in the rule. The relevant landing gear dynamic 
characteristics depend on the parameter chosen by the applicant for use 
in the analysis. The analysis must represent the full energy absorbing 
characteristics of the landing gear and it would be impossible to 
provide an exhaustive list of characteristics that would apply to all 
designs. Typically the manufacturer will validate the dynamic 
characteristics used in the analysis in a gross fashion by using the 
analytical mathematical model to predict the shock absorption response 
time histories in the test for a range of test conditions. In response 
to this comment, changes have been made to the proposed advisory 
material to identify some of the energy absorption components and 
characteristics that are usually of significance and the extent that 
they could be changed or revised without additional testing.
    One commenter is concerned that the elimination of Sec. 25.723(b) 
means that the reserve energy shock absorption tests would no longer be 
required. Removal of Sec. 25.723(b) was not a proposal of Notice 99-08. 
The commenter fails to recognize that the paragraph is represented in 
the notice as a set of asterisks at the end of Sec. 25.723(a) 
signifying that the remaining paragraphs of Sec. 25.723 would remain 
unchanged. However, consideration of the commenters concern brings to 
light the fact that the allowance provided in Sec. 25.723(a)(3) for 
using analysis in lieu of tests, would not necessarily apply to the 
reserve energy drop test of Sec. 25.723(b). In order to correct this

[[Page 27392]]

oversight, Sec. 25.723(b) is clarified, and the allowance in the 
proposed Sec. 25.723(a)(3) is now set forth in a separate 
Sec. 25.723(c) and made applicable to both Secs. 25.723(a) and (b).
    One commenter is concerned that the removal of the free drop test 
requirements in Secs. 25.725 and 25.727 of the rules means that these 
tests would no longer be required and that this could result in a 
reduction in the degree of safety. These specific types of tests, known 
as free drop tests, have never been required. They have always been a 
means of compliance to the general requirement to conduct shock 
absorption tests. This general requirement for conducting shock 
absorption tests remains in the revised Sec. 25.723. The free drop test 
criteria are provided for the manufacturer that chooses to use this 
particular method of performing the required shock absorption tests. In 
the free drop test, the manufacturer may represent the airplane lift by 
using a reduced effective weight for the test. However many 
manufacturers represent the lifting force directly in a drop test or 
perform other types of shock absorption tests. The criteria for 
establishing the effective drop weight is applicable to only this one 
means of compliance and would be more appropriately presented in an 
advisory circular (AC). To this end, AC 25.723-1 ``Shock Absorption 
Tests,'' was made available to provide this means of compliance.
    Two commenters are concerned that the removal of the free drop test 
criteria from the regulation would result in the loss of the current 
method for establishing the effective mass over the nose gear for the 
free drop test. As stated above, this information is not being lost but 
is being moved to an AC as acceptable means of compliance.
    Except for the minor editorial and organizational changes mentioned 
above, the amendment is issued as proposed.

Paperwork Reduction Act

    In accordance with the Paperwork Reduction Act of 1995 (44 U.S.C., 
3507(d)), there are no 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 has 
reviewed the corresponding ICAO Standards and Recommended Practices and 
has identified no differences with 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 Evaluation, 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 upon 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 and, where 
appropriate, that they be the basis of U.S standards. And fourth, the 
Unfunded Mandates Reform Act of 1995 requires agencies to preparer 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, in any 
one year (adjusted for inflation).
    However, for regulations with an expected minimal impact, the 
above-specified analyses are not required. The Department of 
Transportation Order DOT 2100.5 prescribes policies and procedures for 
simplification, analysis, and review of regulations. If it is 
determined that the expected impact is so minimal that the proposal 
does not warrant a full Evaluation, a statement to that effect and the 
basis for it is included in proposed regulation. Since this final rule 
makes landing gear requirements consistent with other requirements in 
the FAR, harmonizes these standards to be consistent with the European 
JAR, and since industry is currently in compliance with the new 
requirements, the expected outcome is to have a minimal cost impact 
with positive net benefits.
    The regulatory evaluation summary examines the costs and benefits 
of a Final Rule entitled Revised Landing Gear Shock Absorption Test 
Requirements. The rule changes the transport category airplane 
certification requirements for landing gear shock absorption tests. 
This amendment to part 25 updates the current standards to take into 
account the structural dynamic flexibility of modern airplanes, the 
complexity of landing gear shock absorption systems, and the ability of 
highly sophisticated computer models to simulate dynamic structural 
loads. The amendment also makes landing gear requirements consistent 
with other requirements in the FAR, harmonizes these standards with 
those being proposed for the European JAR, and is expected to maintain 
the level of safety provided by the test requirements.

Background

    Landing load requirements have evolved as the designs of transport 
category airplanes have changed. Initially, analysis alone was 
considered sufficient for determining the landing load factor that 
would be applied to a rigid airplane. The development of more complex 
landing gear systems and flexible airplanes led to the requirement for 
actual shock absorption tests. Later, the requirement for tests was 
modified to allow analysis alone to substantiate some changes to 
landing gear systems.
    The current landing load requirements in Subpart D (Design and 
Construction) of part 25 require determination of the landing load 
factors for landing gear by means of energy absorption tests (drop 
tests) at maximum takeoff and landing weights. To comply with the 
landing load requirements of Subpart D and the requirements of Subpart 
C (Structure) of part 25, manufacturers build sophisticated computer 
models that comprehensively analyze landing gear and airplane structure 
and accurately represent landing gear shock absorption characteristics. 
These analytical models for landing conditions are validated

[[Page 27393]]

through shock absorption tests (usually drop tests) at the maximum 
takeoff weight and the maximum landing weight.
    The rule will allow manufacturers to validate the analytical 
representation of the dynamic characteristics of landing gear by 
conducting energy absorption tests at the weight (maximum takeoff 
weight or maximum landing weight) which provides the maximum impact 
energy. Because of the ability of the computer models to describe 
landing gear characteristics, tests at weights other than that of 
maximum impact energy are unnecessary. The rule will continue to 
provide for the substantiation of minor changes in landing gear systems 
through the use of the analyses.
    The current Secs. 25.725 and 25.727 are deleted as regulatory 
requirements and moved to a new proposed Advisory Circular 25.723-1, 
except that current Sec. 25.725(c), which describes conditions for the 
attitude of the landing gear and the representation of drag loads 
during the tests, is included in Sec. 25.723.
    This amendment was developed by the ARAC and presented to the FAA 
as a recommendation for rulemaking. This amendment will harmonize shock 
absorption tests with those being proposed by the JAA.

Costs and Benefits

    The requirements, applicable to future type certificated transport 
category airplanes, will result in two regulatory changes: Utilizing 
landing gear energy absorption tests to validate the landing gear 
dynamic characteristics rather than the limit load factor value, and 
confirming energy absorption in characteristics by requiring tests at 
either the maximum landing weight or maximum takeoff weight condition, 
whichever provides the maximum landing impact energy. This is in 
contrast to current requirements, which require tests at both weight 
conditions.
    The tests results will be used to develop the analytical modeling 
of the landing gear dynamic characteristics. These regulatory changes 
are not expected to result in any physical change in the way landing 
gears are tested: the attitude of the gear being usually simulated 
directly by orienting the gear on the rig and drag loads being applied 
by spinning the wheel up to the ground speed. Therefore, it is not 
expected to impose additional costs on manufacturers. This was 
confirmed by two manufacturers. No comments to the contrary were 
received in response to the Notice of Proposed Rulemaking.
    Significant cost savings may result from not having to test both at 
maximum landing weight and maximum takeoff weight, but instead, 
conducting shock absorption in tests only for the conditions associated 
with maximum energy. One manufacturer estimates that this would result 
in 15 fewer test conditions per airplane certification. At a cost of 
$5,000 per condition, the total cost savings as a result of this 
provision equals $75,000 per airplane certification. Another 
manufacturer estimates a cost saving of approximately $190,000 for a 
ten-year period.
    Additionally, by harmonizing the standards of the FAR ad JAR, the 
rule is expected to yield cost savings by eliminating duplicate 
certification activities. One manufacturer ``applauds'' this FAA/JAA 
harmonization effort and its influence on the regulations.
    The imposition of this rule is expected to maintain the current 
level of aviation safety.
    Based on the finding of regulatory cost savings, coupled with the 
cost savings realizable from harmonization, and the expectation that 
these revisions will maintain the existing level of safety provided by 
the test requirements, the FAA has determined that the rule is expected 
to be cost-beneficial.

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.
    The primary effect of this rule is expected to be cost savings for 
aircraft manufacturers. The FAA received no comments regarding its 
earlier assessment of no impact on small entities. The U.S. Small 
Business Administration specifies in its Table of Size Standards of 
March 1, 1996 that, for aircraft manufacturers, a small entity is one 
with 1,500 or fewer employees. Since no part 25 airplane manufacturer 
is believed to have 1,500 or fewer employees, and the rule is expected 
to reduce manufacturing costs, the FAA certifies that the rule is not 
expected to have a significant economic impact on a substantial number 
of small entities.

Unfunded Mandates Reform Act

    The Unfunded Mandates Reform Act of 1995 (the Act), enacted as Pub. 
L. 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 final rule does not contain such a mandate. Therefore, the 
requirements of Title II of the Unfunded Mandates Reform Act of 1995 do 
not apply.

International Trade Impact Assessment

    The Trade Agreement Act of 1979 prohibits Federal agencies from 
setting 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 they be the basis 
for U.S. standards. In addition, consistent with the Administration's 
belief in the general superiority and desirability of free trade, it is 
the policy of the Administration to remove or diminish, to the extent 
feasible, barriers to international trade, including both barriers 
affecting the export of American goods and services to foreign 
countries and barriers affecting the import of foreign goods and 
services into the United States.
    In accordance with the above statute and policy, the FAA has 
assessed the

[[Page 27394]]

potential effect of this rule and has determined that it is not 
expected to constitute a barrier to international trade, including the 
export of American airplanes to foreign countries and the import of 
foreign airplanes into the United States. The requirements in this rule 
are expected to have no adverse impact on trade opportunities for U.S. 
manufacturers selling airplanes in foreign markets and foreign 
manufacturers selling airplanes into the U.S. market. Instead, by 
harmonizing the standards of the FAR and the JAR, it will serve to 
facilitate international trade.

Executive Order 13132, Federalism

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

Regulations Affecting Intrastate 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 CFT in a manner affecting intrastate 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 final 
rule applies to the certification of future designs of transport 
category airplanes and their subsequent operation, it could affect 
intrastate aviation in Alaska. The Administrator has considered the 
extent to which Alaska is not served by transportation modes other than 
aviation, and how the final rule could have been applied directly to 
intrastate operations in Alaska. However, the Administrator has 
determined that airplanes operated solely in Alaska would present the 
same safety concerns as all other affected airplanes; therefore, it 
would be inappropriate to establish a regulatory distinction for the 
intrastate operation of affected airplanes in Alaska.

Environmental Analysis

    Federal Aviation Administration Order 1050.1D defines FAA actions 
that may be categorically excluded from preparation of a National 
Environmental Policy Act (NEPA) environmental impact statement. In 
accordance with FAA Order 1050.ID, appendix 4, paragraph 4(j), this 
amendment qualifies for a categorical exclusion.

Energy Impact

    The energy impact of the amendment has been assessed in accordance 
with the Energy Policy and Conservation Act (EPCA) Pub. L. 94-163, as 
amended (42 U.S.C. 6362) and FAA Order 1053.1. It has been determined 
that the final rule is not a major regulatory action under the 
provisions of the EPCA.

List of Subjects in 14 CFR Part 25

    Air transportation, Aircraft, Aviation safety, Safety.

The Amendment

    In consideration of the foregoing, the Federal Aviation 
Administration amends part 25 of Title 14, Code of Federal Regulations 
(14 CFR part 25) as follows:

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, 44704.

    2. Section 25.473 is amended by revising paragraph (d) to read as 
follows:


Sec. 25.473  Landing load conditions and assumptions.

* * * * *
    (d) The landing gear dynamic characteristics must be validated by 
tests as defined in Sec. 25.723(a).
* * * * *
    3. Section 25.723 is revised to read as follows:


Sec. 25.723  Shock absorption tests.

    (a) The analytical representation of the landing gear dynamic 
characteristics that is used in determining the landing loads must be 
validated by energy absorption tests. A range of tests must be 
conducted to ensure that the analytical representation is valid for the 
design conditions specified in Sec. 25.473.
    (1) The configurations subjected to energy absorption tests at 
limit design conditions must include at least the design landing weight 
or the design takeoff weight, whichever produces the greater value of 
landing impact energy.
    (2) The test attitude of the landing gear unit and the application 
of appropriate drag loads during the test must simulate the airplane 
landing conditions in a manner consistent with the development of 
rational or conservative limit loads.
    (b) The landing gear may not fail in a test, demonstrating its 
reserve energy absorption capacity, simulating a descent velocity of 12 
f.p.s. at design landing weight, assuming airplane lift not greater 
than airplane weight acting during the landing impact.
    (c) In lieu of the tests prescribed in this section, changes in 
previously approved design weights and minor changes in design may be 
substantiated by analyses based on previous tests conducted on the same 
basic landing gear system that has similar energy absorption 
characteristics.


Sec. 25.725  [Reserved]

    4. By removing and reserving Sec. 25.725.


Sec. 25.727  [Reserved]

    5. By removing and reserving Sec. 25.727.

    Issued in Renton, Washington, on May 9, 2001.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service, ANM-100.
[FR Doc. 01-12231 Filed 5-15-01; 8:45 am]
BILLING CODE 4910-13-M