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Revision of Braking Systems; Airworthiness Standards To Harmonize With European Airworthiness Standards for Transport Category Airplanes
Note: EPA no longer updates this information, but it may be useful as a reference or resource.
[Federal Register: December 18, 2000 (Volume 65, Number 243)]
[Proposed Rules]
[Page 79277-79282]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr18de00-35]
[[Page 79277]]
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Part IV
Department of Transportation
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Federal Aviation Administration
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14 CFR Part 25
Revision of Braking Systems; Airworthiness Standards to Harmonize With
European Airworthiness Standards for Transport Category Airplanes;
Proposed Rule
[[Page 79278]]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. FAA-1999-6063; Notice No. 99-16A]
RIN 2120-AG80
Revision of Braking Systems; Airworthiness Standards To Harmonize
With European Airworthiness Standards for Transport Category Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Supplemental notice of proposed rulemaking, (SNPRM).
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SUMMARY: This document seeks public comment on changes proposed as a
result of the comments received on Notice No. 99-16. The changes
proposed in this supplemental notice would require an additional
dynamometer test during brake qualification, namely, an accelerate-stop
test with the brake heat sink in a new condition (also called a new
brake rejected takeoff (RTO) test) for part 25 transport category
airplanes. The new proposed brake test could result in a minimal cost
increase for some part 25 small airplanes. These changes are intended
to benefit the public interest by standardizing certain requirements,
concepts, and procedures in the airworthiness standards without
reducing, but potentially enhancing, the current level of safety.
DATES: Comments must be received on or before February 16, 2001.
ADDRESSES: Address your comments to the Docket Management System, U.S.
Department of Transportation, Room PL 401, 400 Seventh Street, NW,
Washington, DC 20590-0001. You must identify the docket number FAA-
1999-6063 at the beginning of your comments, and you should submit two
copies of your comments. If you wish to receive confirmation that FAA
has received your comments, include a self addressed, stamped postcard.
You may also submit comments through the Internet to: http://
dms.dot.gov. You may review the public docket containing comments to
these proposed regulations in person in the Docket Office between 9:00
a.m. and 5:00 p.m., 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: Mahinder K. Wahi, FAA, Propulsion/
Mechanical Systems Branch, ANM-112, Transport Airplane Directorate,
1601 Lind Avenue SW., Renton, WA 98055-4056; telephone (425) 227-2142;
facsimile (425) 227-1320.
SUPPLEMENTARY INFORMATION:
Comments Invited
Interested persons are invited to participate in the making of the
proposed rule 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 notice are also invited. Substantive comments should
be accompanied by cost estimates. Commenters must identify the
regulatory docket or notice number and submit comments in duplicative
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
rulemaking, will be filed in the docket. The Docket is available for
public inspection before and after the comment closing date.
All comments received on or before the closing date will be
considered by the Administrator before taking action on this proposed
rulemaking. Comments filed late will be considered as far as possible
without incurring expense or delay. The proposals contained in this
notice may be changed in light of the comments received.
Commenters wishing the FAA to acknowledge receipt of their comments
submitted in response to this notice must include a pre-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket No. FAA-1999-6063.'' The postcard will be date stamped and
mailed to the commenter.
Availability of the SNPRM
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 final rule.
You can also get an 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.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 amendment number or docket number of this notice.
Background
On August 10, 1999, the the FAA issued an NPRM titled ``Revision of
Braking Systems Airworthiness Standards To Harmonize With European
Airworthiness Standards for Transport Category Airplanes,'' Notice No.
99-16 (64 FR 43570), and two Notices of Availability, ``Proposed TSO-
C135, Transport Airplane Wheels and Wheel and Brake Assemblies,'' and
``Proposed Advisory Circular (AC) 25.735-1X, Brakes and Braking Systems
Certification Tests and Analysis.'' The related background material
leading to Notice No. 99-16 and the notices of availability is as
follows:
In 1988, the FAA, in cooperation with the JAA and other
organizations representing the American and European aerospace
industries, began a process to harmonize the airworthiness requirements
of the United States and the airworthiness requirements of Europe,
especially in the areas of Flight Test and Structures.
Starting in 1992, the FAA's harmonization effort for various
systems-related airworthiness requirements was undertaken by the ARAC.
A working group of industry and government braking systems specialists
of Europe, the United States, and Canada was chartered by notice in the
Federal Register (59 FR 30080, June 10, 1994). The working group was
tasked to develop a harmonized standard, such as a Technical Standard
Order (TSO), for approval of wheels and brakes to be installed on
transport category airplanes and to develop a draft notice of proposed
rulemaking (NPRM), with supporting economic and other required
analyses, and/or any other related guidance material or collateral
documents, such as advisory circulars, concerning new or revised
requirements and the associated test conditions for wheels, brakes and
braking systems, installed in transport category airplanes
(Secs. 25.731 and 25.735).
The harmonization task was completed by the working group and
recommendations were submitted to the FAA by a letter dated May 1,
1998. The FAA concurred with the
[[Page 79279]]
recommendations and proposed them in Notice No. 99-16. A notice of
availability of proposed TSO-C135 and request for comments and a notice
of availability of proposed AC 25.735-1X and request for comments were
also published in the Federal Register on August 10, 1999 (64 FR
43579). On August 25, 1999, the JAA issued two Notices of Proposed
Amendment (NPA) 25D-291 and NPA TSO-7: ``Brakes and Braking Systems''
that included the proposed advisory material AMJ 25.735. The amendments
proposed in NPA 25D-291 and the advisory material proposed in AMJ
25.735 were substantively the same as the amendments proposed by the
Notice No. 99-16 and the advisory material in proposed AC 25.735-1X.
The NPA TSO-7 was substantively the same as proposed TSO-C135.
As a result, the FAA and JAA each received a set of comments from
the public in response to the proposed rule, the proposed TSO, and the
proposed AC. These two sets of comments are interlinked and addressed
jointly by the FAA in preparing this SNPRM.
Discussion of Comments: Notice 99-16
Twenty-one commenters responded to the request for comments
contained in Notice No. 99-16, the notices of availability of proposed
TSO-C135 and AC 25.735-1, and the corresponding JAA documents NPA 25D-
291, NPA TSO-7, and AMJ 25.735. Comments were received from eight (8)
foreign and domestic airplane and brake manufacturers, nine (9) foreign
airworthiness authorities, one operator and three (3) foreign and
domestic industry organizations. The majority of the commenters agree
with the proposal and recommend its adoption. However, some commenters
disagree with the proposal while providing alternative proposals that
appear to merit further consideration by the ARAC. Therefore, the FAA
tasked the ARAC Braking Systems Harmonization Working Group (HWG) by
letter dated February 8, 2000, to consider the comments and provide
recommendations for the disposition of the comments along with any
recommendations for changes to the proposal. Proposal 11 is the only
proposal relevant to this SNPRM. The disposition of the comments below
is based on the agreement reached by the HWG.
Proposal 11, Sec. 25.735(f)
The proposed paragraph Sec. 25.735(f) in Notice No. 99-16 reads as
follows:
(f) Kinetic energy capacity. The design landing stop, the maximum
kinetic energy accelerate-stop, and the most severe landing stop brake
kinetic energy absorption requirements of each wheel and brake assembly
must be determined. It must be substantiated by dynamometer testing
that, at the declared fully worn limit(s) of the brake heat sink, the
wheel and brake assemblies are capable of absorbing not less than these
levels of kinetic energy. Energy absorption rates defined by the
airplane manufacturer must be achieved. These rates must be equivalent
to mean decelerations not less than 10 fps\2\ for the design landing
stop and 6 fps\2\ for the maximum kinetic energy accelerate stop. The
most severe landing stop need not be considered for extremely
improbable failure conditions or if the maximum kinetic energy
accelerate-stop energy is more severe. Design landing stop is an
operational landing stop at maximum landing weight. Maximum kinetic
energy accelerate-stop is a rejected takeoff for the most critical
combination of airplane takeoff weight and speed. Most severe landing
stop is a stop at the most critical combination of airplane landing
weight and speed.
Comment: One commenter states that as proposed, Sec. 25.735(f) is
difficult to read and contains too many separate requirements in
itself. It could create undue difficulties during the finding of
compliance. It is suggested that the paragraph be re-arranged such
that:
There is a distinct sub-paragraph that can be identified
for the requirement for the determination of the levels of kinetic
energy and the energy absorption rates. This paragraph should indicate
that three cases are to be considered (design landing stop, accelerate-
stop, and most severe landing stop). This sub-paragraph could also
mention the caveats about the need to consider, or not consider, during
testing the most severe landing stop.
There is a distinct sub-paragraph for the requirement for
the wheel and brake assembly to meet the levels of kinetic energy.
There is a distinct sub-paragraph for the requirement for
the wheel and brake assembly to meet the energy absorption rates.
The definitions of the three stop cases (the last 9 lines
of the currently proposed paragraph, starting with: `` . . . Design
landing stop is an operational . . . '') are taken out of the
requirement and placed in the proposed AC 25.735-1X.
The FAA concurs that rearranging Sec. 25.735(f) into three distinct
sub-paragraphs clarifies the requirement. The FAA, however, decided
that it is more appropriate to retain the definitions as part of the
regulatory text, since this is the only place where these terms are
identified.
The text of this paragraph is divided into three subparagraphs
f(1), f(2), and f(3) with appropriate headings. The subparagraphs cover
each of the three tests and include the definitions.
Comment: Two commenters suggest adding a requirement that the
accelerate-stop test, reference: paragraph 3.3.3.2 of the proposed TSO-
C135, and Sec. 25.735(f) of Notice No. 99-16, must be completed on both
a new brake and a fully worn brake. The fully worn brake is the worst
case condition for energy absorption capability, however, the new brake
condition is the worst case condition for performance for some heat
sink materials. (The heat sink is the mass of the brake that is
primarily responsible for absorbing energy during a stop. For a typical
brake, this would consist of the stationary and rotating disc
assemblies.)
The FAA concurs with this comment. Applicable text in the TSO-C135
paragraph 3.3.3.2, and the new Sec. 25.735(f)(2) in this SNPRM add a
new brake accelerate-stop test requirement with the new brake defined
as a brake worn no more than 5 percent of its usable wear range. The
accelerate-stop applicable portion of Sec. 25.735(f) text, Notice No.
99-16, is revised from ``It must be substantiated by dynamometer
testing that, at the declared fully-worn limit(s) of the brake heat
sink, the wheel and brake assemblies are capable of absorbing not less
than these levels of kinetic energy'' to ``(f)(2): It must be
substantiated by dynamometer testing that the wheel, brake, and tire
assembly is capable of absorbing not less than this level of kinetic
energy throughout the defined wear range of the brake.'' Although, not
a part of the TSO, large airplane manufacturers currently require a new
brake RTO test as part of brake qualification. Small airplane
manufacturers may experience a cost increase of $20,000 per
certification.
The New Proposal
The revised proposed rule reads as follows:
(f) Kinetic energy capacity
(1) Design landing stop: The design landing stop is an operational
landing stop at maximum landing weight. The design landing stop brake
kinetic energy absorption requirement of each wheel, brake, and tire
assembly must be determined. It must be substantiated by dynamometer
testing that the wheel, brake and tire assembly is capable of absorbing
not less than this level of kinetic energy throughout the defined wear
range of the brake. The energy absorption rate derived from the
[[Page 79280]]
airplane manufacturer's braking requirements must be achieved. The mean
deceleration must not be less than 10 fps\2\.
(2) Maximum kinetic energy accelerate-stop: The maximum kinetic
energy accelerate-stop is a rejected takeoff for the most critical
combination of airplane takeoff weight and speed. The accelerate-stop
brake kinetic energy absorption requirement of each wheel, brake, and
tire assembly must be determined. It must be substantiated by
dynamometer testing that the wheel, brake, and tire assembly is capable
of absorbing not less than this level of kinetic energy throughout the
defined wear range of the brake. The energy absorption rate defined by
the airplane manufacturer must be achieved. The mean deceleration must
not be less than 6 fps\2\.
(3) Most severe landing stop: The most severe landing stop is a
stop at the most critical combination of airplane landing weight and
speed. The most severe landing stop brake kinetic energy absorption
requirement of each wheel, brake, and tire assembly must be determined.
It must be substantiated by dynamometer testing that, at the declared
fully worn limit(s) of the brake heat sink, the wheel, brake and tire
assembly is capable of absorbing not less than this level of kinetic
energy. The most severe landing stop need not be considered for
extremely improbable failure conditions or if the maximum kinetic
energy accelerate-stop energy is more severe.
The rulemaking proposal contained in this supplemental notice is
based on a recommendation developed by the Braking Systems
Harmonization Working Group, and presented to the FAA by the ARAC as a
recommendation.
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.
Compatibility with ICAO Standards
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. For this
SNPRM, the FAA has determined that there are no ICAO Standards and
Recommended Practices that correspond to these proposed regulations.
Regulatory Evaluation Summary, Regulatory Flexibility Determination,
International Trade Impact Assessment, and Unfunded Mandates Assessment
Proposed 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 effect 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 use those standards as the basis
of U.S. standards. Fourth, Title II of the Unfunded Mandates Reform Act
of 1995 requires each Federal agency, to the extent permitted by law,
to prepare a written assessment of the effects of any Federal mandate
in a proposed or final agency rule that may result in the expenditure
by State, local, and tribal governments, in the aggregate, or by the
private sector, of $100 million in any one year. In conducting these
analyses, the FAA has determined that this supplemental proposal: (1)
Would generate benefits that justify its costs and is not ``a
significant regulatory action'' as defined in Executive Order 12866 or
in the Department of Transportation's Regulatory Policies and
Procedures; (2) would not have a significant impact on a substantial
number of small entities; (3) would not constitute a barrier to
international trade, and (4) does not contain a Federal
intergovernmental or private sector mandate that exceeds $100 million
in any one year.
These analyses, available in the docket, are summarized below. All
estimates are expressed in year 2000 dollars.
Regulatory Evaluation Summary
Summary of Major Economic Issues in NPRM 99-16
Of several revisions proposed for 14 CFR 25.735, only one, proposal
11, was expected to impose additional costs, estimated at $20,000 to
$60,000 (the latter upper estimate has been reduced to $40,000) for
part 25 large airplanes and $20,000 (as explained below, the latter
estimate has been increased to a range of $20,000 to $40,000) for part
25 small airplanes. Most of the changes codify current industry
practice or conform 14 CFR 25.735 to corresponding sections of the JAR.
The resulting regulatory harmonization would eliminate unnecessary
duplication of airworthiness requirements, thus reducing manufacturers'
certification costs.
None of the commenters disputes FAA's estimates of specific
incremental certification costs. One commenter, however, questions
FAA's contention that costs would be balanced by the savings from rule
harmonization, and further objects to the vagueness of the expected
safety benefits. The FAA disagrees with the latter commenter's synopsis
of the benefits' conclusion in the NPRM. The FAA did not contend that
quantified benefits from averted future accidents alone would
economically justify the proposed rule. Although total harmonization
savings were not specified, the FAA nevertheless stated that
``according to one manufacturer, cost savings from harmonization * * *
would be equal to or greater than the maximum incremental cost of
$60,000.'' The FAA also noted that ``potential safety benefits
resulting from specification of minimum accepted standards would
supplement these cost savings.'' In addition, even though none of the
previous accidents would have been directly preventable by the proposed
amendments, ``different designs in future type certifications, however,
could present other problems (unexpected) and raise future accident
rates.''
Notwithstanding the above, since publication of Notice 99-16, the
FAA has contacted industry sources to obtain estimates of harmonization
cost savings attributable to the revisions originally proposed in the
Notice. These cost savings would be, at a minimum, between $50,000 and
$75,000 for a part 25 small airplane type certification and $100,000 to
$300,000 for a part 25 large airplane type certification. These
harmonization benefits would exceed the incremental costs of all the
revisions specified in the NPRM as well as the costs attributable to
the SNPRM change.
Supplemental Change and Associated Costs and Benefits
The proposed dynamometer test, also called a new brake rejected
takeoff (RTO) test, is currently conducted by brake manufacturers as
specified by large airplane manufacturers during brake qualification
testing and is considered standard industry practice. For some
manufacturers of part 25 small airplanes, however, the proposed test
could result in a cost increase of
[[Page 79281]]
$20,000 per type certification (thus increasing incremental costs for
proposal 11 in the NPRM from an estimated $20,000 to a range of $20,000
to $40,000). This incremental but nonrecurring cost for some
manufacturers of part 25 small airplanes would easily be offset by the
harmonization cost savings cited earlier. Any potential safety benefits
from avoiding even one minor accident would add to such benefits. The
FAA, therefore, finds the additional change to proposal 11 to be cost
beneficial for both part 25 small and large airplane manufacturers.
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 RFA.
However, if an agency determines that a proposed or final rule is
not expected to have a significant 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 the
factual basis for this determination, and the reasoning should be
clear.
This SNPRM would affect manufacturers of transport category
airplanes produced under future new airplane type certifications. For
airplane manufacturers, a small entity is one with 1,500 or fewer
employees. Since no part 25 airplane manufacturer has 1,500 or fewer
employees, the FAA certifies that the rule will not have a significant
economic impact on a substantial number of small manufacturers.
International Trade Impact Assessment
Consistent with the Administration's belief in the general
superiority, desirability, and efficacy of free trade, it is the policy
of the Administrator 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 those
affecting the import of foreign goods and services into the United
States.
In accordance with that policy, the FAA is committed to develop as
much as possible its aviation standards and practices in harmony with
its trading partners. Significant cost savings can result from this,
both to United States' companies doing business in foreign markets, and
foreign companies doing business in the United States.
The subject proposal is a direct action to respond to this policy
by increasing the harmonization of the U.S. Federal Aviation
Regulations with the European Joint Aviation Requirements. The result
would be a positive step toward removing impediments to international
trade.
Unfunded Mandates Reform Act
Title II of the Unfunded Mandates Reform Act of 1995 (the Act),
enacted as Public Law 104-4 on March 22, 1995 (the Act), codified in 2
U.S.C. 1501-1571, requires each Federal agency, to the extent permitted
by law, to prepare a written assessment of the effects of any Federal
mandate in a proposed or final agency rule that may result in the
expenditure by State, local, and tribal governments, in the aggregate,
or by the private sector, of $100 million or more (adjusted annually
for inflation) in any one year.
This supplemental proposal does not contain a Federal
intergovernmental or private sector mandate that exceeds $100 million
in any one year. Therefore, the requirements of Title II of the
Unfunded Mandates Reform Act of 1995 do not apply.
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.
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. Therefore, we determined that this proposed rule does 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 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 notice has been assessed in accordance
with the Energy Policy and Conservation Act (EPCA) Public Law 94-163,
as amended (42 U.S.C. 6362) and FAA Order 1053.1. It has been
determined that the notice is not a major regulatory action under the
provisions of the EPCA.
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:
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. Amend Sec. 25.735 for revising the heading and paragraph (f) to
read as follows:
Sec. 25.735 Brakes and braking systems.
* * * * *
(f) Kinetic energy capacity
(1) Design landing stop: The design landing stop is an operational
landing stop at maximum landing weight. The design landing stop brake
kinetic energy
[[Page 79282]]
absorption requirement of each wheel, brake, and tire assembly must be
determined. It must be substantiated by dynamometer testing that the
wheel, brake and tire assembly is capable of absorbing not less than
this level of kinetic energy throughout the defined wear range of the
brake. The energy absorption rate derived from the airplane
manufacturer's braking requirements must be achieved. The mean
deceleration must not be less than 10 fps.\2\
(2) Maximum kinetic energy accelerate-stop: The maximum kinetic
energy accelerate-stop is a rejected takeoff for the most critical
combination of airplane takeoff weight and speed. The accelerate-stop
brake kinetic energy absorption requirement of each wheel, brake, and
tire assembly must be determined. It must be substantiated by
dynamometer testing that the wheel, brake, and tire assembly is capable
of absorbing not less than this level of kinetic energy throughout the
defined wear range of the brake. The energy absorption rate defined by
the airplane manufacturer must be achieved. The mean deceleration must
not be less than 6 fps.\2\
(3) Most severe landing stop: The most severe landing stop is a
stop at the most critical combination of airplane landing weight and
speed. The most severe landing stop brake kinetic energy absorption
requirement of each wheel, brake, and tire assembly must be determined.
It must be substantiated by dynamometer testing that, at the declared
fully worn limit(s) of the brake heat sink, the wheel, brake and tire
assembly is capable of absorbing not less than this level of kinetic
energy. The most severe landing stop need not be considered for
extremely improbable failure conditions or if the maximum kinetic
energy accelerate-stop energy is more severe.
* * * * *
Issued in Renton, Washington on December 4, 2000.
John J. Hickey,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 00-31927 Filed 12-15-00; 8:45 am]
BILLING CODE 4910-13-U