29070 Federal Register / Vol. 63, No. 101 /Wednesday, May 27, 1998 /Rules and Regulations

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.

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–

SBREFA@faa.dot.gov.

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, § 25.493, and

its predecessor rule, § 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
Federal Register / Vol. 63, No. 101 /Wednesday, May 27, 1998 /Rules and Regulations 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

§ 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 § 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

§ 25.493 of the FAR with § 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
29072 Federal Register / Vol. 63, No. 101 /Wednesday, May 27, 1998 /Rules and Regulations

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:

§ 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:

V W

A B

B f AE

A B E N

T = +

+

+ +





 



 μ

μ

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.

μ=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:

f = + −

−















 1

1 2 exp πξ

ξ

Where:

ξ is the effective critical damping ratio

of the rigid body pitching mode

about the main landing gear

effective ground contact point.
Federal Register / Vol. 63, No. 101 /Wednesday, May 27, 1998 /Rules and Regulations 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