[Federal Register Volume 60, Number 73 (Monday, April 17, 1995)]
[Proposed Rules]
[Pages 19181-19183]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-9348]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 95-NM-40-AD]
Airworthiness Directives; Boeing Model 737 Series Airplanes
Equipped With BFGoodrich Main Landing Gear Brake Assemblies
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: This document proposes the adoption of a new airworthiness
directive (AD) that is applicable to certain Boeing Model 737 series
airplanes. This proposal would require inspection of certain brake
assemblies to determine the part number of the torque plates,
measurement of the amount of wear remaining on the brake wear pin
indicator, and removal of brake assemblies on which misidentified
torque plates were installed and replacement with serviceable brakes.
This proposal is prompted by a report that certain torque plates were
misidentified and installed on certain brake assemblies. The actions
specified by the proposed AD are intended to prevent decreased brake
performance during a rejected takeoff or landing when these brakes are
at or near their indicated wear limit. (The brake wear pin indicator
would falsely indicate longer remaining wear because of the
misidentified longer torque plates that were installed on these brake
assemblies.)
DATES: Comments must be received by May 11, 1995.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 95-NM-40-AD, 1601 Lind Avenue, SW., Renton,
Washington 98055-4056. Comments may be inspected at this location
between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal
holidays.
The service information referenced in the proposed rule may be
obtained from BFGoodrich Aerospace, Aircraft Wheels and Brakes, P.O.
Box 340, Troy, Ohio 45373. This information may be examined at the FAA,
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton,
Washington.
FOR FURTHER INFORMATION CONTACT: David M. Herron, Aerospace Engineer,
Systems and Equipment Branch, ANM-130S, FAA, Transport Airplane
Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue,
SW., Renton, Washington 98055-4056; telephone (206) 227-2672; fax (206)
227-1181.
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. Communications shall identify the Rules Docket number
and be submitted in triplicate to the address specified above. All
communications received on or before the closing date for comments,
specified above, will be considered before taking action on the
proposed rule. The proposals contained in this notice may be changed in
light of the comments received.
Comments are specifically invited on the overall regulatory,
economic, environmental, and energy aspects of the proposed rule. All
comments submitted will be available, both before and after the closing
date for comments, in the Rules Docket for examination by interested
persons. A report summarizing each FAA-public contact concerned with
the substance of this proposal will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments
submitted in response to this notice must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 95-NM-40-AD.'' The postcard will be date stamped and
returned to the commenter.
Availability of NPRMs
Any person may obtain a copy of this NPRM by submitting a request
to the FAA, Transport Airplane Directorate, ANM-103, Attention: Rules
Docket No. 94-NM-40-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
Recently, BFGoodrich shipped some torque plates that were
misidentified as [[Page 19182]] part number (P/N) 184-875, when, in
reality, they were P/N 184-884. These misidentified torque plates were
installed on Boeing Model 737 series airplanes with main landing gear
brake assemblies having BFGoodrich P/N's 2-1474-1, -2, -3, and -5
(Boeing P/N's 10-61819-22, -26, -27, and -31). Torque plates having P/N
184-884 should be installed on brake assemblies having P/N 2-1474-7.
Although these two torque plates are similar in appearance, the
essential difference is that torque plates having P/N 184-884 are 0.240
inch longer than torque plates having P/N 184-875. Therefore, the FAA
has determined that brake assemblies having BFGoodrich P/N 2-1474-1, -
2, -3, or -5 on which the misidentified torque plates were installed,
would falsely indicate a longer remaining wear on the brake wear pin
indicator. This condition, if not corrected, could result in decreased
brake performance during a rejected takeoff or landing when these
brakes are at or near their indicated wear limit.
BFGoodrich has issued Service Bulletin 2-1474-32-17, dated January
26, 1995, which describes procedures for a one-time inspection of the
brake assemblies on Model 737 series airplanes to determine the P/N of
the torque plates. This service bulletin also describes procedures for
measurement of the amount of wear remaining on the brake wear pin
indicator, and removal of brake assemblies having BFGoodrich P/N 2-
1474-1, -2, -3, or -5 on which the misidentified torque plates were
installed and replacement with serviceable brakes.
Since an unsafe condition has been identified that is likely to
exist or develop on other products of this same type design, the
proposed AD would require a one-time inspection of certain brake
assemblies on Model 737 series airplanes to determine the P/N of the
torque plates. This proposed AD would also require measurement of the
amount of wear remaining on the brake wear pin indicator, and removal
of brake assemblies on which misidentified torque plates were installed
and replacement with serviceable brakes. The actions would be required
to be accomplished in accordance with the service bulletin described
previously.
This proposal permits, for a period of up to 30 days after the
effective date of the rule, installation of brake assemblies having
BFGoodrich P/N 2-1474-1, -2, -3, or -5 on which misidentified torque
plates, P/N 184-884, have been installed. The FAA has determined such
replacement will not compromise safety of the fleet since the life
expectancy of these brakes is typically 90 to 120 days.
As a result of recent communications with the Air Transport
Association (ATA) of America, the FAA has learned that, in general,
some operators may misunderstand the legal effect of AD's on airplanes
that are identified in the applicability provision of the AD, but that
have been altered or repaired in the area addressed by the AD. The FAA
points out that all airplanes identified in the applicability provision
of an AD are legally subject to the AD. If an airplane has been altered
or repaired in the affected area in such a way as to affect compliance
with the AD, the owner or operator is required to obtain FAA approval
for an alternative method of compliance with the AD, in accordance with
the paragraph of each AD that provides for such approvals. A note has
been included in this notice to clarify this long-standing requirement.
There are approximately 717 Model 737 series airplanes equipped
with BFGoodrich main landing gear brake assemblies of the affected
design in the worldwide fleet. The FAA estimates that 325 airplanes of
U.S. registry would be affected by this proposed AD, that it would take
approximately 0.25 work hour per airplane to accomplish the proposed
actions, and that the average labor rate is $60 per work hour. Based on
these figures, the total cost impact of the proposed AD on U.S.
operators is estimated to be $4,875, or $15 per airplane.
The total cost impact figure discussed above is based on
assumptions that no operator has yet accomplished any of the proposed
requirements of this AD action, and that no operator would accomplish
those actions in the future if this AD were not adopted.
The regulations proposed herein would 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
proposal would not have sufficient federalism implications to warrant
the preparation of a Federalism Assessment.
For the reasons discussed above, I certify that this proposed
regulation (1) is not a ``significant regulatory action'' under
Executive Order 12866; (2) is not a ``significant rule'' under the DOT
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979);
and (3) if promulgated, 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 copy of the draft
regulatory evaluation prepared for this action is contained in the
Rules Docket. A copy of it may be obtained by contacting 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.
The Proposed Amendment
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration proposes to amend
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:
Boeing: Docket 95-NM-40-AD.
Applicability: Model 737 series airplanes equipped with
BFGoodrich main landing gear brake assemblies having part numbers
(P/N) 2-1474-1, -2, -3, or -5 (Boeing P/N's 10-61819-22, -26, -27,
or -31); certificated in any category.
Note 1: This AD applies to each airplane identified in the
preceding applicability provision, regardless of whether it has been
modified, altered, or repaired in the area subject to the
requirements of this AD. For airplanes that have been modified,
altered, or repaired so that the performance of the requirements of
this AD is affected, the owner/operator must use the authority
provided in paragraph (d) to request approval from the FAA. This
approval may address either no action, if the current configuration
eliminates the unsafe condition; or different actions necessary to
address the unsafe condition described in this AD. Such a request
should include an assessment of the effect of the changed
configuration on the unsafe condition addressed by this AD. In no
case does the presence of any modification, alteration, or repair
remove any airplane from the applicability of this AD.
Compliance: Required as indicated, unless accomplished
previously.
To prevent decreased brake performance during a rejected takeoff
or landing when these brakes are at or near their indicated wear
limit, accomplish the following:
(a) Within 30 days after the effective date of this AD, perform
an inspection of the brake assembly to determine the part number (P/
N) of the torque plate, in accordance with BFGoodrich Service
Bulletin 2-1474-32-17, dated January 26, 1995. [[Page 19183]]
(b) If the P/N is 184-790, -790-1, -790-2, -790-3, or -875, no
further action is required by this paragraph.
(c) If the P/N does not coincide with one identified in
paragraph (b) of this AD, prior to further flight, measure the
amount of wear remaining on the brake wear pin indicator, in
accordance with service bulletin. Remove and replace the brake prior
to the time specified in paragraph (c)(1), (c)(2), or (c)(3) of this
AD, as applicable.
(1) If the remaining wear on the brake wear pin indicator is
equivalent to 0.260 inch or more: Prior to the accumulation of 40
flight cycles, remove that brake assembly and replace it with a
serviceable brake assembly, in accordance with the service bulletin.
If the brake assembly is replaced with a brake assembly having
BFGoodrich P/N 2-1474-1, -2, -3, or -5 on which a torque plate
having P/N 184-884 has been installed, replace that brake assembly
prior to the accumulation of 40 flight cycles since installation. As
of 30 days after the effective date of this AD, no person shall
install on any airplane, a brake assembly, BFGoodrich P/N 2-1474-1,
-2, -3, or -5 (Boeing P/N 10-61819-22, -26, -27, or -31), on which a
torque plate having P/N 184-884 has been installed.
(2) If the remaining wear on the brake wear pin indicator is
less than 0.260 inch but more than 0.240 inch: Remove that brake
assembly and replace it with a serviceable brake assembly, in
accordance with the service bulletin. Use the following formula to
determine when the brake assembly must be removed and replaced:
(measurement of wear remaining on brake wear pin indicator) - (0.240
inch) x (1,000 flight cycles) = (time, expressed in number of
flight cycles, prior to which brake assembly must be removed and
replaced). As of 30 days after the effective date of this AD, no
person shall install on any airplane, a brake assembly, BFGoodrich
P/N 2-1474-1, -2, -3, or -5 (Boeing P/N 10-61819-22, -26, -27, or -
31), on which a torque plate having P/N 184-884 has been installed.
(3) If the remaining wear on the brake wear pin indicator is
equivalent to 0.240 inch or less: Prior to further flight, remove
that brake assembly and replace it with a serviceable brake
assembly, in accordance with the service bulletin. As of 30 days
after the effective date of this AD, no person shall install on any
airplane, a brake assembly, BFGoodrich P/N 2-1474-1, -2, -3, or -5
(Boeing P/N 10-61819-22, -26, -27, or -31), on which a torque plate
having P/N 184-884 has been installed.
(d) 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, Seattle Aircraft Certification
Office (ACO), 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, Seattle ACO.
Note 2: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Seattle ACO.
(e) 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.
Issued in Renton, Washington, on April 11, 1995.
S.R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 95-9348 Filed 4-14-95; 8:45 am]
BILLING CODE 4910-13-U
