[Federal Register Volume 62, Number 140 (Tuesday, July 22, 1997)]
[Proposed Rules]
[Pages 39195-39197]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-19176]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-52-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 767 Series Airplanes

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 767 series 
airplanes. This proposal would require repetitive inspections to detect 
corrosion or plating cracks of the pin assemblies in the forward 
trunnion support of the main landing gear (MLG), and replacement of the 
pin assembly with a new assembly, if necessary. Such replacement, if 
accomplished, would constitute terminating action for the repetitive 
inspections. This proposal is prompted by reports indicating that these 
pin assemblies were found to have corroded as a result of plating 
cracks. The actions specified by the proposed AD are intended to detect 
and correct such corrosion and plating cracks, which could cause 
breakage of these assemblies, and consequent collapse of the MLG.

DATES: Comments must be received by September 2, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 97-NM-52-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 Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, 
Washington 98124-2207. This information may be examined at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington.

FOR FURTHER INFORMATION CONTACT: James G. Rehrl, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington; telephone (425) 227-2783; 
fax (425) 227-1181.

[[Page 39196]]

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 97-NM-52-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. 97-NM-52-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received several reports of corrosion on pin assemblies 
in the forward trunnion support of the main landing gear (MLG) 
installed on Boeing Model 767 series airplanes. At the time these 
corroded pin assemblies were found, the airplanes had accumulated 
between 6,900 and 12,600 total landings.
    The manufacturer performed a review of several pin assemblies and 
determined that the bond between the 4330M Steel pin and its Class 2 
chrome plating is not sufficient to prevent the plating from cracking 
and peeling. Such cracking and peeling provide sites for moisture to 
corrode the pin. Corrosion of these pin assemblies, if not detected and 
corrected in a timely manner, could cause breakage of the pin 
assemblies, and consequent collapse of the MLG.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
767-57A0047, Revision 1, dated May 9, 1996, which describes procedures 
for repetitive close visual inspections to detect corrosion or plating 
cracks of the 4330M Steel pin assemblies in the forward trunnion 
support of the MLG, and replacement of the pin assembly with a new 
asembly, if necessary. Replacement of pin assemblies with new ones made 
from a different material and finish would eliminate the need for 
further inspections of those assemblies. The new assemblies are made 
from 15-5PH CRES with Class 3 chrome plating, and are more resistant to 
corrosion and plating cracks.

Explanation of Requirements of Proposed Rule

    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 repetitive close visual inspections to detect 
corrosion or plating cracks of the 4330M Steel pin assemblies in the 
forward trunnion support of the MLG, and replacement of the pin 
assembly with a new assembly, if necessary. Such replacement would 
constitute terminating action for the repetitive inspections.
    The actions would be required to be accomplished in accordance with 
the service bulletin described previously.

Cost Impact

    There are approximately 562 Boeing Model 767 series airplanes of 
the affected design in the worldwide fleet. The FAA estimates that 151 
airplanes of U.S. registry would be affected by this proposed AD, that 
it would take approximately 65 work hours per airplane to accomplish 
the proposed inspection, and that the average labor rate is $60 per 
work hour. Based on these figures, the cost impact of the proposed AD 
on U.S. operators is estimated to be $588,900, or $3,900 per airplane, 
per inspection cycle.
    The 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.

Regulatory Impact

    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. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

Boeing: Docket 97-NM-52-AD.

    Applicability: Model 767 series airplanes having line positions 
1 through 562 inclusive, certificated in any category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
otherwise 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 request approval for an 
alternative method of compliance in accordance with paragraph (e) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or repair on the unsafe condition 
addressed by this AD; and, if the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.


[[Page 39197]]


    Compliance: Required as indicated, unless accomplished 
previously.
    To detect and correct corrosion or plating cracks of the pin 
assemblies in the front trunnion support of the main landing gear 
(MLG), which could cause these assemblies to break and result in 
collapse of the MLG, accomplish the following:
    (a) Perform a close visual inspection to detect corrosion or 
plating cracks of each 4330M Steel pin assembly in the forward 
trunnion support of the MLG, in accordance with Boeing Alert Service 
Bulletin 767-57A0047, Revision 1, dated May 9, 1996, at the later of 
the times specified in paragraphs (a)(1) and (a)(2) of this AD.
    (1) Within 4 years since date of manufacture of the airplane, or 
4 years since the last overhaul of the MLG. Or
    (2) Within 18 months after the effective date of this AD.
    (b) If no corrosion or crack is detected, repeat the close 
visual inspection thereafter at intervals not to exceed 48 months.
    (c) If any corrosion or crack is detected, prior to further 
flight, replace it with a new pin assembly made from 15-5PH CRES 
with Class 3 chrome plating, in accordance with Boeing Alert Service 
Bulletin 767-57A0047, Revision 1, dated May 9, 1996.
    (d) Accomplishment of replacement of a 4330M Steel pin assembly 
with a new pin assembly made from 15-5PH CRES with Class 3 chrome 
plating, in accordance with Boeing Alert Service Bulletin 767-
57A0047, Revision 1, dated May 9, 1996, constitutes terminating 
action for the inspections required by this AD for that pin 
location.

    Note 2: Replacement of a 4330M Steel pin assembly with a new pin 
assembly made from 15-5PH CRES with Class 3 chrome plating prior to 
the effective date of this AD, in accordance with Boeing Service 
Bulletin 767-57A0047, dated January 19, 1995, is considered an 
acceptable method of compliance with paragraph (d) of this AD for 
that pin location.

    (e) 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 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

    (f) Special flight permits may be issued in accordance with 
sections 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 July 16, 1997.
Gary L. Killion,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-19176 Filed 7-21-97; 8:45 am]
BILLING CODE 4910-13-P