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Federal Register / Vol. 86, No. 123 / Wednesday, June 30, 2021 / Proposed Rules fax: 2062313528; email:
allen.rauschendorfer@faa.gov.
SUPPLEMENTARY INFORMATION:

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Comments Invited The FAA invites you to send any written relevant data, views, or arguments about this proposal. Send your comments to an address listed under ADDRESSES. Include Docket No.
FAA20210457; Project Identifier AD
202001461T at the beginning of your comments. The most helpful comments reference a specific portion of the proposal, explain the reason for any recommended change, and include supporting data. The FAA will consider all comments received by the closing date and may amend this proposal because of those comments.
Except for Confidential Business Information CBI as described in the following paragraph, and other information as described in 14 CFR
11.35, the FAA will post all comments received, without change, to https
www.regulations.gov, including any personal information you provide. The agency will also post a report summarizing each substantive verbal contact received about this NPRM.
Confidential Business Information CBI is commercial or financial information that is both customarily and actually treated as private by its owner.
Under the Freedom of Information Act FOIA 5 U.S.C. 552, CBI is exempt from public disclosure. If your comments responsive to this NPRM
contain commercial or financial information that is customarily treated as private, that you actually treat as private, and that is relevant or responsive to this NPRM, it is important that you clearly designate the submitted comments as CBI. Please mark each page of your submission containing CBI
as PROPIN. The FAA will treat such marked submissions as confidential under the FOIA, and they will not be placed in the public docket of this NPRM. Submissions containing CBI
should be sent to Allen Rauschendorfer, Senior Aerospace Engineer, Airframe Section, FAA, Seattle ACO Branch, 2200
South 216th St., Des Moines, WA 98198;
phone and fax: 2062313528; email:
allen.rauschendorfer@faa.gov. Any commentary that the FAA receives which is not specifically designated as CBI will be placed in the public docket for this rulemaking.
Background The FAA has received a report indicating that during a fleet sampling inspection, cracks were found on the inner cylinder pivot pins of the left and
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right MLG on one of the airplanes. The pins exhibited cracking of the high velocity oxygen fuel HVOF tungsten carbide-cobalt-chrome coating. Removal of the outer diameter coating disclosed cracking of the custom 465 CRES
substrate. The cause of the cracking was determined to be heat damage due to inservice friction. This condition, if not addressed, could result in a fractured pivot pin, which could lead to loss of all or part of the pivot pin assembly, and subsequent collapse of the MLG and reduced controllability of the airplane during takeoff and landing.
FAAs Determination The FAA is issuing this NPRM after determining that the unsafe condition described previously is likely to exist or develop on other products of the same type design.
Related Service Information Under 1
CFR Part 51
The FAA reviewed Boeing Alert Requirements Bulletin B78781205
SB32004500 RB, Issue 001, dated November 9, 2020. This service information specifies procedures for repetitive lubrication of the left and right MLG truck beam and inner cylinder pivot joint with MILPRF
32014 grease, reviewing the maintenance program documentation to verify that it includes lubrication tasks for the left and right MLG truck beam and inner cylinder pivot joint with MILPRF32014 grease, repetitive detailed and fluorescent penetrant inspections FPI of the left and right MLG pivot pin outer diameter OD
surface for any friction and heat damage, repetitive detailed inspections of the left and right MLG inner cylinder bushing inner diameter ID surface for any excessive wear, cracking and smearing of bushing material, and applicable on-condition actions.
On-condition actions include updating the maintenance program to incorporate lubrication tasks for the left and right MLG truck beam and inner cylinder pivot joint with MILPRF
32014 grease, detailed and FPI
inspections on the inner cylinder lug bore for any heat and friction damage, installing a new pivot pin, applying lubrication using MILPRF32014
grease and making sure lubrication passages are clear, installing new aluminum-nickel-bronze inner cylinder bushings, installing new copper-nickeltin inner cylinder bushings, and repair.
The service information also specifies terminating actions for the repetitive inspections. The terminating actions include the installation of certain parts
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and incorporation of the lubrications tasks into the maintenance program.
The FAA also reviewed Boeing 787
Certification Maintenance Requirements CMRs, D011Z0090303, dated June 2020. This service information specifies procedures for, among other actions, for CMR item number 32CMR01, to lubricate the main landing gear truck beam pivot joint.
This service information is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in ADDRESSES.
Proposed AD Requirements in This NPRM
This proposed AD would require accomplishing the actions specified in the service information already described except for any differences identified as exceptions in the regulatory text of this proposed AD. For information on the procedures and compliance times, see this service information at https
www.regulations.gov by searching for and locating Docket No. FAA2021
0457.
Boeing Alert Requirements Bulletin B78781205SB32004500 RB, Issue 001, dated November 9, 2020, specifies updating the maintenance program to incorporate lubrication tasks for the left and right MLG truck beam and inner cylinder pivot joint with MILPRF
32014 grease. Operators have different methods of updating the maintenance program. If operators want to terminate the repetitive lubrications required by paragraph g of this AD, only revising the maintenance or inspection program, as applicable, to incorporate CMR item number 32CMR01 of Section G, Certification Maintenance Requirement Task, of Boeing 787 Certification Maintenance Requirements CMRs, D011Z0090303, dated June 2020, is terminating action.
This proposed AD includes an optional action that would include revisions to certain operator maintenance documents to include new actions e.g., inspections. Compliance with these actions is required by 14 CFR
91.403c. For airplanes that have been previously modified, altered, or repaired in the areas addressed by this proposed AD, the operator may not be able to accomplish the actions described in the revisions. In this situation, to comply with 14 CFR 91.403c, the operator must request approval for an alternative method of compliance according to paragraph l of this proposed AD.

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