[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