Airworthiness Directives; Airbus Industrie Model A300, A300-600, A310, and A320 Series Airplanes

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 93-NM-227-AD; Amendment 39-9101; AD 94-26-05]

Airworthiness Directives; Airbus Industrie Model A300, A300-600,

A310, and A320 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD),

applicable to certain Airbus Industrie Model A300, A300-600, A310, and

A320 series airplanes, that requires inspection of certain landing gear

brakes for wear and replacement if the wear limits prescribed in this

AD are not met, and incorporation of the specified wear limits into the

FAA-approved maintenance inspection program. This amendment is prompted

by an accident in which a transport category airplane executed a

rejected takeoff (RTO) and was unable to stop on the runway due to worn

brakes; and the subsequent review of allowable brake wear limits for

all transport category airplanes. The actions specified by this AD are

intended to prevent the loss of brake effectiveness during a high

energy RTO.

EFFECTIVE DATE: January 23, 1995.

ADDRESSES: Information pertaining to this rulemaking action may be

examined at the Federal Aviation Administration (FAA), Transport

Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton,

Washington; or at the Office of the Federal Register, 800 North Capitol

Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Mark Quam, Aerospace Engineer,

Standardization Branch, ANM-113, FAA, Transport Airplane Directorate,

1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206)

227-2145; fax (206) 227-1320.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal

Aviation Regulations (14 CFR part 39) to include an airworthiness

directive (AD) that is applicable to certain Airbus Industrie Model

A300, A300-600, A310, and A320 series airplanes was published in the

Federal Register on February 15, 1994 (59 FR 7228). That action

proposed to require inspection of certain landing gear brakes for wear

and replacement if the wear limits prescribed in this AD are not met,

and incorporation of the specified wear limits into the FAA-approved

maintenance inspection program.

Interested persons have been afforded an opportunity to participate

in the making of this amendment. Due consideration has been given to

the comments received.

One commenter supports the proposed rule.

One commenter, BFGoodrich, requests that the tables contained in

the proposal that list maximum brake wear limits for the affected

airplanes be revised. BFGoodrich indicates that the airplane model/

series listed for BFGoodrich series 2-1526 brake part numbers should be

``A320,'' instead of ``A320-220'' and ``A320-200.'' The commenter also

indicates that three additional part numbers for BFGoodrich brakes

should be listed in the tables for Model A320 series airplanes: Part

numbers 2-1526, 2-1526-5 (both with maximum wear limits of 1.97''), and

2-1572 (with a maximum wear limit of 2.68'').

While the FAA agrees with the commenter's remarks, inclusion of the

three additional part numbers specified by the commenter would

necessitate (under the provisions of the Administrative Procedure Act)

reissuing the notice, reopening the period for public comment,

considering additional comments received, and eventually issuing a

final rule; the time required for that procedure may be as long as four

additional months. In the interest of issuing this final rule, and in

consideration of the amount of time that has already elapsed since

issuance of the original notice, the FAA has determined that further

delay of this final rule action is not appropriate. However, the FAA

may consider further rulemaking on this issue to address the three

additional part numbers discussed by the commenter.

The Air Transport Association (ATA) of America, on behalf of one of

its members, suggests that measuring the maximum length of the wear pin

may not be as effective as measuring the total length of the wear pin

or controlling the carbon thickness of the brake. The commenter points

out that, due to human error, it is possible to have a thinner disc

with the same amount of wear pin length showing.

The FAA does not concur. The FAA infers from the commenter's

remarks that it is referring to controlling the carbon thickness of the

brakes by direct measurement of the thickness of the brake stack. The

FAA finds that measuring the thickness of the brake stack would only be

useful when specifying the brake assembly configuration and the

thicknesses of new, refurbished, or overhauled individual discs.

Otherwise, a brake disc that is too thin also could be installed in a

brake stack having a wear limit that is controlled by measuring the

stack thickness. Further, it would not be practical to routinely

measure the brake stack on the airplane as all of the wheels attached

to the brakes would have to be removed to allow access to accomplish

the measurement. The FAA considers that this would pose an unwarranted

burden on operators. Currently, only the wear pin must be monitored

while the brake is installed on the airplane. If an operator reduces

the wear limit, the pin could be shortened or the operator could devise

a method of accounting for the reduced wear using the existing wear pin

as opposed to removing the wheel and measuring the brake stack. (Thus,

the wheels would not have to be removed from the airplane since the

wear pin can still be used to monitor brake wear.)

The wear limits specified in this AD, which are used to establish

wear pin lengths, are interdependent with the brake configuration and

minimum disc and stack thicknesses. The stack and disc thicknesses are

specified for new, refurbished, or overhauled brakes in the airplane

maintenance manual (AMM), the component maintenance manual (CMM), a

service bulletin, or the brake manufacturer's assembly drawings. These

minimum brake stack and disc thicknesses have been established by tests

and in-service wear data and analysis such that monitoring a wear pin

should not allow the stack or disc minimum limits to be exceeded.

The ATA also questions the need for the proposed AD, and requests

that a provision be included in paragraph (a)(2) of the AD to state

that the AD would no longer be applicable to operators that have

acceptably revised their maintenance programs, and that operators

choosing this provision could use an alternative recordkeeping method

in lieu of that required by Secs. 91.417 or 121.380 of the Federal

Aviation Regulations (14 CFR 91.417 or 121.380). The FAA would be

defined as the cognizant Principal Maintenance Inspector (PMI) for

operators electing this alternative.

The ATA states that if its suggested provision is not included,

confusion will always exist as to what records should be maintained for

the duration A300/A320 operations. The ATA maintains that once an

operator incorporates the criteria (brake wear limits) specified in the

proposal into the maintenance program, the AD should be signed off as

complete, since such incorporation is the stated purpose of the AD. The

ATA is aware of an FAA concern that the proposed type of rule must

continue indefinitely because operators may otherwise escalate

intervals through their reliability programs. The ATA states that

adjustments to operators' programs are accomplished with substantiation

and with the approval of FAA Flight Standards District Offices (FSDO).

The ATA maintains that FAA FSDO's have sufficient authority to ensure

that operators maintain the brakes on their Model A300/A320 series

airplanes once the proposed criteria (brake wear limits) have been

incorporated into an operator's maintenance program.

The FAA does not concur. The intent of this AD is that operators

incorporate maximum brake wear limits into the FAA-approved maintenance

inspection program, and that all brakes be inspected once for wear and

replaced, if necessary. Once an operator has complied with the

requirements of this AD, the FAA does not intend that operators

subsequently record the accomplishment of this AD each time a brake is

inspected or overhauled in accordance with that operator's FAA-approved

maintenance inspection program. ``NOTE 2'' has been added to paragraph

(a) of the final rule to clarify this intent. Operators should

coordinate recordkeeping for accomplishment of the actions required by

this AD with the cognizant Principal Maintenance Inspector (PMI).

One ATA member requests that carbon brakes be excluded from the

applicability of the proposed rule. Airbus adds its concurrence with

the ATA member's request, and has advised the ATA that all carbon

brakes installed on airplanes manufactured by Airbus are capable of

sustaining a maximum energy rejected takeoff (RTO) in a 100 percent

worn brake configuration. Airbus also states that no unsafe condition

has been identified for airplanes having carbon brakes.

Airbus also indicates that issuance of an AD to require

implementation of existing CMM limits would impose unnecessary

inspections (with associated costs) and would create an unnecessary

paperwork burden on operators. Airbus states that, if the proposed rule

is adopted, then an inspection would be required for all airplanes, not

just the 28 airplanes specified in the economic impact information of

the proposal.

The FAA does not concur. As discussed in the preamble of the

proposal, this AD, as well as other previously issued AD's to mandate

specific maximum brake wear limits on transport category airplanes, was

prompted by an accident in 1988 involving worn brakes on a McDonnell

Douglas Model DC-10 series airplane. During the process of promulgating

those AD's, the FAA became aware that not all operators were following

the manufacturer's recommended brake wear limits. The FAA acknowledges

that the wear limits for carbon brakes have not changed. However, the

purpose of this AD is simply to establish the correct brake wear limits

for the affected airplanes, including those on which carbon brakes

having unchanged brake wear limits, are installed.

The FAA acknowledges that operators of airplanes having carbon

brakes will be required to confirm that inspections are being

accomplished and to record compliance with this AD. However, if an

operator already operates in accordance with the wear limits specified

in this AD, as implied by ATA and Airbus, then only the costs

associated with confirming compliance with the AD and recording such

compliance are necessary. The economic impact information specified

below addresses 46 airplanes that will be required to accomplish the

inspection specified in this AD. (This number, 46, has been revised

from the 28 airplanes specified in the proposal; the FAA's latest

information is that 46 airplanes will be affected by the inspection

requirement.) However, carbon brakes may be installed on some of those

airplanes; therefore, some of the 46 airplanes addressed in this AD

already may be operated in accordance with its provisions. Therefore,

the actual total cost impact of this AD on U.S. operators may be less

than the cost reflected in the cost estimate information, below.

One commenter requests that the brake wear limit specified in the

proposed rule for brake part numbers 2-1526-3 and 2-1526-4 should be

revised to read 2.68'' (68 mm), rather than 1.97'' (50 mm). The

commenter indicates that the maximum brake wear limit of 1.97'' (50 mm)

is already standard for brake part numbers 2-1526-1 and 2-1526-2,

whereas a wear limit of 2.68'' (68 mm) is specified in the CMM for

brake part numbers 2-1526-3 and 2-1526-4 due to a different

configuration that allows greater wear pin length and still maintains

RTO performance at the maximum wear limit.

The FAA finds that no change to the final rule is necessary in this

regard. The proposed rule, as published in the Federal Register on

February 15, 1994, specified the correct brake wear limit of 2.68'' (68

mm) for brake part numbers 2-1526-3 and 2-1526-4. That same brake wear

limit is contained in this final rule.

After careful review of the available data, including the comments

noted above, the FAA has determined that air safety and the public

interest require the adoption of the rule with the changes previously

described. The FAA has determined that these changes will neither

increase the economic burden on any operator nor increase the scope of

the AD.

The FAA has recently reviewed the figures it has used over the past

several years in calculating the economic impact of AD activity. In

order to account for various inflationary costs in the airline

industry, the FAA has determined that it is necessary to increase the

labor rate used in these calculations from $55 per work hour to $60 per

work hour. The economic impact information, below, has been revised to

reflect this increase in the specified hourly labor rate. In addition

to the number of affected airplanes of U.S. registry that will be

required to accomplish the inspection (as discussed previously), the

FAA has updated the total number of airplanes of U.S. registry and the

number of affected U.S. operators to reflect the latest information

available.

The FAA estimates that 165 Model A300, A300-600, A310, and A320

series airplanes of U.S. registry and 7 U.S. operators will be affected

by this AD, that it will take approximately 20 work hours per operator,

at an average labor rate of $60 per work hour, for each operator to

incorporate the revision of its FAA-approved maintenance inspection

program. Based on these figures, the total cost impact of that

requirement on U.S. operators is estimated to be $8,400, or $1,200 per

operator.

The FAA also estimates that it will take 15 work hours per

airplane, at an average labor rate of $60 per work hour, to accomplish

the required inspection. The cost of required parts to accomplish the

change in wear limits for these airplanes (that is, the cost resulting

from the requirement to change the brakes before they are worn to their

previously approved limits for a one-time change) will be approximately

$2,236 per airplane. The FAA estimates that 46 of the 165 affected

airplanes of U.S. registry will be required to accomplish the

inspection. Based on these figures, the total cost impact of that

requirement on U.S. operators of these airplanes is estimated to be

$144,256, or $3,136 per airplane.

The total cost impact figure discussed above is based on

assumptions that no affected operator has accomplished all of the

requirements of this AD action, and that no affected operator would

accomplish all of those actions in the future if this AD were not

adopted.

The regulations adopted 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 final

rule does not have sufficient federalism implications to warrant the

preparation of a Federalism Assessment.

For the reasons discussed above, I certify that this action (1) is

not a ``significant regulatory action'' under Executive Order 12866;

(2) is not a ``significant rule'' under DOT Regulatory Policies and

Procedures (44 FR 11034, February 26, 1979); and (3) will not have a

significant economic impact, positive or negative, on a substantial

number of small entities under the criteria of the Regulatory

Flexibility Act. A final evaluation has been prepared for this action

and it is contained in the Rules Docket. A copy of it may be obtained

from the Rules Docket at the location provided under the caption

ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Safety.

Adoption of the Amendment

Accordingly, pursuant to the authority delegated to me by the

Administrator, the Federal Aviation Administration amends part 39 of

the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39--AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C.

106(g); and 14 CFR 11.89.

Sec. 39.13 [Amended]

2. Section 39.13 is amended by adding the following new

airworthiness directive:

94-26-05 Airbus Industrie: Amendment 39-9101. Docket 93-NM-227-AD.

Applicability: Model A300, A300-600, A310, and A320 series

airplanes equipped with Messier-Bugatti, BFGoodrich, Allied Signal

(ALS) Aerospace Company (Bendix), or Aircraft Braking Systems (ABS)

brakes; certificated in any category.

Compliance: Required as indicated, unless accomplished

previously.

To prevent the loss of brake effectiveness during a high energy

rejected takeoff (RTO), accomplish the following:

(a) Within 180 days after the effective date of this AD,

accomplish paragraphs (a)(1) and (a)(2) of this AD.

(1) Inspect main landing gear brakes having the brake part

numbers listed below for wear. Any brake worn more than the maximum

wear limit specified below must be replaced, prior to further

flight, with a brake within that limit.

Airbus Industrie Model A300, A300-600, A310, and A320 Series Airplanes Equipped With Messier-Bugatti,

BFGoodrich, Allied Signal (ALS) Aerospace Company (Bendix), or Aircraft Braking Systems (ABS) Brakes

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Maximum brake wear limit (inch/

Airplane model/series Brake manufacturer Brake part No. mm)

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A300-B2-100-........... Messier-Bugatti........ 286349-115 0.98'' (25.0 mm)

A300-B2-100-........... Messier-Bugatti........ 286349-116 0.98'' (25.0 mm)

A300-B2-100-........... BFGoodrich............. 2-1449 1.4'' (35.6 mm)

A300-B2-100-........... BFGoodrich............. 2-1449 1.1'' (27.9 mm) S.C.*

A300-B4-100-........... Messier-Bugatti........ A21329-41-7- 1.1'' (28.0 mm)

A300-B4-100-........... Messier-Bugatti........ A21329-41-17 1.1'' (28.0 mm)

A300-B4-100-........... ALS (Bendix)........... 2606802-3/-4/-5 0.9'' (22.9 mm)

A300-B4-100-........... ALS (Bendix)........... 2606802-3/-4/-5 1.48'' (37.6 mm) S.C.*

A300-B4-100-........... BFGoodrich............. 2-1449 1.4'' (35.6 mm)

A300-B4-100-........... BFGoodrich............. 2-1449 1.1'' (27.9 mm) S.C.*

A300-B4-200 & A300-600. Messier-Bugatti........ C20060-100 1.1'' (28.0 mm)

A300-B4-200 & A300-600. ALS (Bendix)........... 2607932-1 0.9'' (22.9 mm)

A300-B4-200 & A300-600. ALS (Bendix)........... 2607932-1 1.48'' (37.6 mm) S.C.*

A300-B4-600R........... Messier-Bugatti........ C20210000 1.97'' (50.0 mm)

A300-B4-600R........... Messier-Bugatti........ C20210200 1.97'' (50.0 mm)

A310-200............... Messier-Bugatti........ C20089000 1.1'' (28.0 mm)

A310-200............... ALS (Bendix)........... 2606822-1 1.26'' (32.0 mm)

A310-200............... ALS (Bendix)........... 2606822-1 1.5'' (38.2 mm) S.C.*

A310-300............... Messier-Bugatti........ C20194000 1.97'' (50.0 mm)

A310-300............... Messier-Bugatti........ C20194200 1.97'' (50.0 mm)

A310-300............... ABS.................... 5010995 1.97'' (50.0 mm

A320................... Messier-Bugatti........ C20225000 1.97'' (50.0 mm)

A320................... Messier-Bugatti........ C20225200 1.97'' (50.0 mm)

A320................... BFGoodrich............. 2-1526-2 1.97'' (50.0 mm)

A320................... BFGoodrich............. 2-1526-3/-4 2.68'' (68.0 mm)

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* S.C. represents ``Service Configured'' brakes, which are marked according to the instructions provided in the

brake manufacturer's Component Maintenance Manual.

Note 1: Measuring instructions that must be revised to

accommodate the new brake wear limits specified above can be found

in Chapter 32-42-27 of the Airplane Maintenance Manual (AMM), in

Chapter 32-32-( ) or 32-44-( ) of the brake manufacturer's Component

Maintenance Manual (CMM), or in certain service bulletins (SB), as

listed below:

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Date/Revision (or later

Brake manufacturer Part No. Document/chapter revisions)

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For Model A300-B2-100 Series Airplanes:

Messier-Bugatti............................ 286349-115 CMM 32-42-27 Apr. 1991.

Messier-Bugatti............................ 286349-116 CMM 32-42-27 Apr. 1991.

BFGoodrich................................. 2-1449 & S.C. CMM 32-44-37 Jan. 1993.

................................. SB 567 (2-1449-32-4) Jan. 30, 1993.

For Model A300-B4-100 Series Airplanes:

ALS (Bendix)............................... 2606802-3 CMM 32-42-02 Sept. 1993.

2606802-4 SB 2606802-32-003 Mar. 31, 1993.

2606802-5 & S.C.

BFGoodrich................................. 2-1449 & S.C. CMM 32-44-37 Jan. 1993.

SB 567 (2-1449-32-4) Jan. 30, 1993.

For Model A300-B4-200 and A300-600 Series

Airplanes:

ALS (Bendix)............................... 2607932-1 & S.C. CMM 32-42-27 Sept. 1993.

SB 2607932-32-002 Mar. 31, 1993 & Revision

1, dated.

Oct. 1, 1993.

For Model A300-B4-600R Series Airplanes:

Messier-Bugatti............................ C20210000 & C20210200 Airbus SB 470-32-675 Apr. 6, 1990.

For Model A310-200 Series Airplanes:

ALS (Bendix)............................... 2606822-1 & S.B. CMM 32-42-03 Sept. 1993.

SB 2606822-32-002 Mar. 31, 1993.

For Model A310-300 Series Airplanes:

Messier-Bugatti............................ C20225000-& C20225200 Airbus SB-470-32-675 Apr. 6, 1990.

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(2) Incorporate into the FAA-approved maintenance inspection

program the maximum brake wear limits specified in paragraph (a)(1)

of this AD.

Note 2: Once an operator has complied with the requirements of

this AD, paragraphs (a)(1) and (a)(2) of this AD do not require that

operators subsequently record accomplishment of this AD each time a

brake is inspected or overhauled in accordance with that operator's

FAA-approved maintenance inspection program.

(b) An alternative method of compliance or adjustment of the

compliance time that provides an acceptable level of safety may be

used if approved by the Manager, Standardization Branch, ANM-113,

FAA, Transport Airplane Directorate. Operators shall submit their

requests through an appropriate FAA Principal Maintenance Inspector,

who may add comments and then send it to the Manager,

Standardization Branch, ANM-113.

Note 3: Information concerning the existence of approved

alternative methods of compliance with this AD, if any, may be

obtained from the Standardization Branch, ANM-113.

(c) Special flight permits may be issued in accordance with

Secs. 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR

21.197 and 21.199) to operate the airplane to a location where the

requirements of this AD can be accomplished.

(d) This amendment becomes effective on January 23, 1995.

Issued in Renton, Washington, on December 14, 1994.

Darrell M. Pederson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-31179 Filed 12-21-94; 8:45 am]

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