[Federal Register Volume 63, Number 101 (Wednesday, May 27, 1998)]
[Rules and Regulations]
[Pages 29070-29073]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-13999]
[[Page 29069]]
_______________________________________________________________________
Part III
Department of Transportation
_______________________________________________________________________
Federal Aviation Administration
_______________________________________________________________________
14 CFR Part 25
Braked Roll Conditions; Final Rule
Federal Register / Vol. 63, No. 101 / Wednesday, May 27, 1998 / Rules
and Regulations
[[Page 29070]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. 28643; Amdt. No. 25-97]
RIN 2120-AF83
Braked Roll Conditions
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
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SUMMARY: This amendment to the airworthiness standards for transport
category airplanes adds a new design standard that requires that the
airplane be designed to withstand main landing gear maximum braking
forces during ground operations. This amendment will ensure that the
landing gear and fuselage are capable of withstanding the dynamic loads
associated with the maximum dynamic braking condition. It also relieves
a burden on industry by eliminating differences between the Federal
Aviation Regulations (FAR) and European Joint Aviation Requirements
(JAR), while maintaining a level of safety provided by the current
regulations and industry practices.
EFFECTIVE DATE: June 26, 1998.
FOR FURTHER INFORMATION CONTACT: Jim Haynes, FAA, Airframe and
Airworthiness Branch (ANM-115), Transport Airplane Directorate,
Aircraft Certification Service, 1601 Lind Avenue SW., Renton,
Washington 98055-4056; telephone (425) 227-2131; facsimile (425) 227-
1320.
SUPPLEMENTARY INFORMATION:
Availability of Final Rule
An electronic copy of this document may be downloaded using a modem
and suitable communications software from the FAA regulations section
of the FedWorld electronic bulletin board service (telephone: 202-512-
1661) or the FAA's Aviation Rulemaking Advisory Committee Bulletin
Board service (telephone: 800-FAA-ARAC).
Internet users may reach the FAA's web page at http://www.faa.gov
or the Federal Register's webpage at http://www.access.gpo.gov/su_docs
for access to recently published rulemaking documents.
Any person may obtain a copy of this final rule 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. Communications must identify the amendment
number or document number of this final rule.
Persons interested in being placed on the mailing list for future
notices of proposed rulemaking and final rules should request from the
above office a copy of Advisory Circular (AC) No. 11-2A, Notice of
Proposed Rulemaking Distribution System, which describes the
application procedure.
Small Entity Inquiries
The Small Business Regulatory Enforcement Fairness Act of 1996
(SBREFA) requires the FAA to report inquiries from small entities
concerning information on, and advice about, compliance with statutes
and regulations within the FAA's jurisdiction, including interpretation
and application of the law to specific sets of facts supplied by a
small entity.
The FAA's definitions of small entities may be accessed through the
FAA's web page (http://www.faa.gov.avr/arm/sbrefa.htm), by contacting a
local FAA official, or by contacting the FAA's Small Entity Contact
listed below.
If you are a small entity and have a question, contact your local
FAA official. If you do not know how to contact your local FAA
official, you may contact Charlene Brown, Program Analyst Staff, Office
of Rulemaking, ARM-27, Federal Aviation Administration, 800
Independence Avenue, SW, Washington, DC 20591, 1-888-551-1594. Internet
users can find additional information on SBREFA in the ``Quick Jump''
section of the FAA's web page at http://www.faa.gov and may send
electronic inquiries to the following internet address: 9-AWA-
[email protected].
Background
This amendment is based on Notice of Proposed Rulemaking (NPRM) 96-
10, which was published in the Federal Register on August 5, 1996 (61
FR 40710). The notice was based on a need to protect the airframe
structure from damage during hard application of the brakes.
The current 14 CFR part 25 airworthiness standards, Sec. 25.493,
and its predecessor rule, Sec. 4b.235(b) of the Civil Air Regulations
(CAR), prescribe braked roll conditions that the airplane structure and
landing gear must be designed to withstand during airplane taxiing with
a constant (steady) application of brakes (``braked roll'' condition).
The taxi condition is generally the most critical condition regarding
nose gear and forward fuselage loading during the braking event, due to
the increased braking coefficient of friction at low speeds and the
lack of lift on the wings and lack of aerodynamic damping. Both rules
treat the braked roll condition as a static equilibrium condition.
Neither rule accounts for the dynamic loads on the nose gear and
fuselage associated with pitch inertia of the airplane due to rapid
application of main landing gear brakes. Adequate strength has been
achieved on existing airplanes by application of other part 25 design
requirements and by the manufacturers' need to comply with the more
stringent British Civil Airworthiness Requirements (BCAR).
For many years the BCAR have included a dynamic braking condition
that requires that consideration be given to the maximum likely
combination of dynamic vertical reaction and sudden increase in drag
load that could occur on the nose gear as a result of sudden main gear
braking while encountering obstacles. The BCAR address obstacles such
as overruns onto semi-prepared surfaces during rejected takeoffs,
running off the edge then back on to the runway during avoidance
maneuvers, running over displaced or lowered edges of runway paving,
and inadvertent use of runways under repair. In application of the BCAR
requirement, it was found that U.S. designed airplanes generally have
had adequate strength to meet this condition without requiring any
modifications. However, this may not always be the case, especially if
new airplane designs are significantly different from past conventional
configurations in vertical and longitudinal mass distributions of fuel,
payload, engine location, etc. As the takeoff weight increases with
respect to landing weight, the dynamic braked roll condition can become
more critical for the nose gear and fuselage. This amendment will
ensure that all future airplanes will be provided with adequate
strength in the fuselage and nose landing gear to carry these loads.
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. The
objective was to achieve common requirements for the certification of
transport airplanes without a substantive change in the level of safety
provided by the regulations. Other airworthiness authorities such as
Transport Canada also participated in this process.
In 1992, the harmonization effort was undertaken by the Aviation
Rulemaking Advisory Committee (ARAC). A working group of industry and
government structural loads specialists of Europe, the United States,
and
[[Page 29071]]
Canada was chartered by notice in the Federal Register (58 FR 13819,
March 15, 1993) to harmonize the design loads sections of Subpart C of
part 25. The harmonization effort on the braked roll rule was
accomplished and a specific proposal was recommended to the FAA by
letter dated November 6, 1995. The FAA concurred with the
recommendation, and published Notice 96-10 in the Federal Register on
August 5, 1996, for public comment.
Interested persons have been given an opportunity to participate in
this rulemaking and due consideration has been given to all matters
presented. Comments received in response to Notice 96-10 are discussed
below.
Discussion of Comments
The FAA received three comments in response to Notice 96-10. Two of
these commenters support the proposal, one with comment, while the
third commenter objects to the proposal.
One commenter, representing the aviation industry, supports the
proposal but expresses concern about possible interpretation of the
rule. This commenter states that it is industry's belief that the
proposed rule represented a harmonized position on both the rule and
the interpretative advisory material; specifically, the commenter
supports JAA interpretation and advisory material which allows use of a
coefficient of friction less than 0.80, when substantiated, in the
formula of Sec. 25.493(c). The commenter requests that this
interpretation be clarified. The coefficient of friction of 0.80
between the tire and ground surface has been used for structural design
of the landing gear and structure since it was codified in the Civil
Air Regulations (CAR Part 4b). The FAA has allowed a lower drag
reaction in those cases where it can be substantiated that an effective
drag force of 0.80 times the vertical reaction cannot be attained under
any likely loading condition. This has generally been interpreted to
mean that a lower drag force may be used where maximum brake torque is
the limiting factor. This allowance is provided in the current
regulation and is unchanged by this amendment. A value of 0.80 remains
as the value of the coefficient of friction in the regulatory formula
of Sec. 25.493(e).
One commenter, an aircraft manufacturer, believes the proposed
regulation is unnecessary because the braked roll condition is not the
loading condition that determines the design of the nose gear and
fuselage. The commenter states that a three point landing is typically
the load condition which determines the design of the landing gear
structure, which is far more severe than the braked roll conditions
addressed in the notice. The FAA agrees that this may be true for most
airplane designs; however, it is not always the case. The FAA considers
the rule necessary to ensure proper landing gear designs for those
airplanes that are affected by the braked roll condition.
In view of the above, part 25 is amended as proposed in Notice 96-
10.
Regulatory 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 effects of regulatory changes on small entities. Third, the
Office of Management and Budget directs agencies to assess the effects
of regulatory changes on international trade. Fourth, the Unfunded
Mandates Reform Act of 1995 (Pub. L. 104-4) requires agencies to
prepare a written assessment of the costs, benefits and other effects
of proposed or final rules that include a Federal mandate likely to
result in the expenditure by State, local or tribal governments, in the
aggregate, or by the private sector, of $100 million or more annually
(adjusted for inflation). In conducting these analyses, which are
summarized below (and available in the docket), the FAA has determined
that this rule is not ``a significant regulatory action'' under section
3(f) of Executive Order 12866 and therefore was not reviewed by the
Office of Management and Budget. The rule is not considered significant
under Department of Transportation Regulatory Policies and Procedures
(44 FR 11034, February 26, 1979). In addition, for the reasons stated
under the ``Regulatory Flexibility Determination,'' the ``International
Trade Impact Assessment,'' and the ``Unfunded Mandates Assessment,''
the FAA certifies that this rule will not have a significant economic
impact on a substantial number of small entities, will not constitute a
barrier to international trade, and will not result in the expenditure
by State, local, or tribal governments, in the aggregate, or by the
private sector, of $100 million or more annually.
Regulatory Evaluation Summary
As stated in the preamble to the notice, the rule change will
codify current industry practice (thus maintaining at least the current
level of safety) and will not impose additional costs on manufacturers
of transport category airplanes. Adequate strength has been achieved on
existing airplanes by application of other part 25 design requirements
and by manufacturers' needs to comply with the more stringent BCAR in
order to sell airplanes overseas. Moreover, by conforming Sec. 25.493
of the FAR with Sec. 25.493 of the JAR, the new amendment will increase
harmonization between American and European airworthiness standards and
potentially reduce duplicate certification costs.
Regulatory Flexibility Determination
The Regulatory Flexibility Act of 1980 (RFA) was enacted by
Congress to ensure that small entities are not unnecessarily or
disproportionately burdened by Government regulations. The RFA requires
a Regulatory Flexibility Analysis, in which alternatives are identified
and evaluated, if a rule is expected to have ``a significant economic
impact on a substantial number of small entities.'' The Small Business
Administration (SBA) has established standards for complying with RFA
review requirements in Federal rulemaking actions; the standards
specify small entity size by Standard Industrial Classification (SIC).
The rule change will affect manufacturers of transport category
airplanes produced under new type certificates. The SBA specifies a
size threshold for classification as a small entity as 1,500 or fewer
employees. Since the rule will impose no incremental costs on airplane
manufacturers (and, additionally, no part 25 airplane manufacturer has
1,500 or fewer employees), the rule change will not have a significant
economic impact on a substantial number of small entities.
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 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 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
[[Page 29072]]
companies doing business in foreign markets, and foreign companies
doing business in the United States.
This rule 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 will be a
positive step toward removing impediments to international trade.
Unfunded Mandates Assessment
Title II of the Unfunded Mandates Reform Act of 1995 (the Act),
enacted as Pub. L. 104-4 on March 22, 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 or more (adjusted annually for inflation) in any one year.
Section 204(a) of the Act, 2 U.S.C. 1534(a), requires the Federal
agency to develop an effective process to permit timely input by
elected officers (or their designees) of State, local, and tribal
governments on a proposed ``significant intergovernmental mandate.'' A
``significant intergovernmental mandate'' under the Act is any
provision in a Federal agency regulation that will impose an
enforceable duty upon State, local, and tribal governments, in the
aggregate, of $100 million (adjusted annually for inflation) in any one
year. Section 203 of the Act, 2 U.S.C. 1533, which supplements section
204(a), provides that before establishing any regulatory requirements
that might significantly or uniquely affect small governments, the
agency shall have developed a plan that, among other things, provides
for notice to potentially affected small governments, if any, and for a
meaningful and timely opportunity to provide input in the development
of regulatory proposals.
The FAA has determined that this rule does not contain a
significant intergovernmental or private sector mandate as defined by
the Act.
Federalism Implications
The regulation amended herein will not have substantial direct
effects 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, in
accordance with Executive Order 12612, it is determined that this
regulation will not have sufficient federalism implications to warrant
the preparation of a Federalism Assessment.
International Civil Aviation Organization (ICAO) and Joint Aviation
Regulations
In keeping with U.S. obligations under the Convention on
International Civil Aviation, it is FAA policy to comply with ICAO
Standards and Recommended Practices to the maximum extent practicable.
The FAA has determined that this rule does not conflict with any
international agreement of the United States.
Paperwork Reduction Act
In accordance with the Paperwork Reduction Act of 1995 (44 U.S.C.
3507(d)), there are no reporting or recordkeeping requirements
associated with this rule.
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 CFR 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 differently 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.
List of Subjects in 14 CFR Part 25
Aircraft, Aviation safety, Reporting and recordkeeping
requirements.
Adoption of the Amendment
In consideration of the foregoing, the Federal Aviation
Administration (FAA) amends 14 CFR part 25 of the Federal Aviation
Regulations (FAR) as follows:
PART 25--AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES
1. The authority citation for part 25 continues to read:
Authority: 49 U.S.C. 106(g), 40113, 44701, 44702, and 44704.
2. Section 25.493 is amended by revising paragraph (c) and by
adding new paragraphs (d) and (e) to read as follows:
Sec. 25.493 Braked roll conditions.
* * * * *
(c) A drag reaction lower than that prescribed in this section may
be used if it is substantiated that an effective drag force of 0.8
times the vertical reaction cannot be attained under any likely loading
condition.
(d) An airplane equipped with a nose gear must be designed to
withstand the loads arising from the dynamic pitching motion of the
airplane due to sudden application of maximum braking force. The
airplane is considered to be at design takeoff weight with the nose and
main gears in contact with the ground, and with a steady-state vertical
load factor of 1.0. The steady-state nose gear reaction must be
combined with the maximum incremental nose gear vertical reaction
caused by the sudden application of maximum braking force as described
in paragraphs (b) and (c) of this section.
(e) In the absence of a more rational analysis, the nose gear
vertical reaction prescribed in paragraph (d) of this section must be
calculated according to the following formula:
[GRAPHIC] [TIFF OMITTED] TR27MY98.017
Where:
VN=Nose gear vertical reaction.
WT=Design takeoff weight.
A=Horizontal distance between the c.g. of the airplane and the nose
wheel.
B=Horizontal distance between the c.g. of the airplane and the line
joining the centers of the main wheels.
E=Vertical height of the c.g. of the airplane above the ground in the
1.0 g static condition.
=Coefficient of friction of 0.80.
f=Dynamic response factor; 2.0 is to be used unless a lower factor is
substantiated. In the absence of other information, the dynamic
response factor f may be defined by the equation:
[GRAPHIC] [TIFF OMITTED] TR27MY98.018
Where:
is the effective critical damping ratio of the rigid body
pitching mode about the main landing gear effective ground contact
point.
[[Page 29073]]
Issued in Washington, DC, on May 18, 1998.
Jane F. Garvey,
Administrator.
[FR Doc. 98-13999 Filed 5-26-98; 8:45 am]
BILLING CODE 4910-13-P