[Federal Register Volume 59, Number 245 (Thursday, December 22, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-31179]
[[Page Unknown]]
[Federal Register: December 22, 1994]
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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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