[4910-13-P]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2024-1690; Project Identifier AD-2024-00083-T]
RIN 2120-AA64
Airworthiness Directives; The Boeing Company Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) for all The
Boeing Company (Boeing) Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, 747SP, and 747SR series
airplanes. This proposed AD was prompted by a report of improper inner diameter
grinding of landing gear outer cylinders, resulting in possible heat damage to the outer
cylinder of the nose landing gear (NLG), body landing gear (BLG), and wing landing
gear (WLG). This proposed AD would require replacing any affected outer cylinders.
The FAA is proposing this AD to address the unsafe condition on these products.
DATES: The FAA must receive comments on this proposed AD by [INSERT DATE 45
DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER].
ADDRESSES: You may send comments, using the procedures found in 14 CFR 11.43
and 11.45, by any of the following methods:
• Federal eRulemaking Portal: Go to regulations.gov. Follow the instructions for
submitting comments.
• Fax: 202-493-2251.

• Mail: U.S. Department of Transportation, Docket Operations, M-30, West
Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC
20590.
• Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m.,
Monday through Friday, except Federal holidays.
AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA2024-1690; or in person at Docket Operations between 9 a.m. and 5 p.m., Monday
through Friday, except Federal holidays. The AD docket contains this NPRM, any
comments received, and other information. The street address for Docket Operations is
listed above.
Material Incorporated by Reference:
• For The Boeing Company service information, contact Boeing Commercial
Airplanes, Attention: Contractual & Data Services (C&DS), 2600 Westminster
Boulevard, MC 110-SK57, Seal Beach, CA 90740-5600; telephone 562-797-1717;
website myboeingfleet.com.
• You may view this service information at the FAA, Airworthiness Products
Section, Operational Safety Branch, 2200 South 216th Street, Des Moines, WA. For
information on the availability of this material at the FAA, call 206-231-3195. It is also
available at regulations.gov by searching for and locating Docket No. FAA-2024-1690.
FOR FURTHER INFORMATION CONTACT: Stefanie Roesli, Aviation Safety
Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; telephone 206-231-3964;
email stefanie.n.roesli@faa.gov.
SUPPLEMENTARY INFORMATION:
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. FAA-2024-1690; Project Identifier AD-2024-00083-T” 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 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 Stefanie Roesli,
Aviation Safety Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198;
telephone 206-231-3964; email stefanie.n.roesli@faa.gov. Any commentary that the FAA
receives that is not specifically designated as CBI will be placed in the public docket for
this rulemaking.

Background
The FAA has received a report of a main landing gear collapse event on a Boeing
Model 767 airplane that was last overhauled at a maintenance, repair, and operations
(MRO) facility. The MRO facility identified a grinder that was operating outside of its
input parameters, which could cause heat damage to the outer cylinder of the NLG, BLG,
and WLG. The MRO facility identified 67 Boeing Model 747 landing gear outer
cylinders which had inner diameter grinding performed with the suspect grinder. This
condition, if not addressed, could cause the failure of a principal structural element to
sustain its limit load or collapse of the landing gear, which may result in loss of control of
the airplane or a runway departure. A failure of an outer cylinder could also deviate from
the intended breakaway sequence, which could result in a failed part impacting the fuel
tank and spilling fuel and consequently creating a fire hazard.
FAA’s 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 747-32A2535 RB, dated
January 22, 2024. This service information specifies determining whether the outer
cylinder of the NLG, the right and left WLG, and the right and left BLG have an affected
part number and serial number and replacing all affected outer cylinders.
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 regulations.gov under Docket No. FAA2024-1690.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would affect 168
airplanes of U.S. registry. The FAA estimates the following costs to comply with this
proposed AD:
Estimated costs

Action

Labor cost

Parts cost

Cost per
product

Cost on
U.S.
operators

Inspection or
maintenance
records check for
affected parts

3 work-hours X
$85 per hour =
$255

$0

$255

$42,840

The FAA estimates the following costs to do any replacements that would be
required based on the results of the proposed inspection or maintenance records check.
The agency has no way of determining the number of airplanes that might need this
replacement:
On-condition costs
Action

Labor cost

Parts cost

Cost per
product

Cost on U.S.
operators

Replacement of
outer cylinder
(67 affected parts)

161 work-hours X
$85 per hour =
$13,685

$325,000

$338,685

$22,691,895
(67 affected
parts)

Authority for this Rulemaking
Title 49 of the United States Code specifies the FAA’s authority to issue rules on

aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator.
Subtitle VII: Aviation Programs, describes in more detail the scope of the Agency’s
authority.
The FAA is issuing this rulemaking under the authority described in Subtitle VII,
Part A, Subpart III, Section 44701: General requirements. Under that section, Congress
charges the FAA with promoting safe flight of civil aircraft in air commerce by
prescribing regulations for practices, methods, and procedures the Administrator finds
necessary for safety in air commerce. This regulation is within the scope of that authority
because it addresses an unsafe condition that is likely to exist or develop on products
identified in this rulemaking action.
Regulatory Findings
The FAA determined that this proposed AD would not have federalism
implications under Executive Order 13132. This proposed AD would not have a
substantial direct effect 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.
For the reasons discussed above, I certify this proposed regulation:
(1) Is not a “significant regulatory action” under Executive Order 12866,
(2) Would not affect intrastate aviation in Alaska, and
(3) Would not have a significant economic impact, positive or negative, on a
substantial number of small entities under the criteria of the Regulatory Flexibility Act.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.
The Proposed Amendment
Accordingly, under the authority delegated to me by the Administrator, the FAA
proposes to amend 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.
§ 39.13 [Amended]
2. The FAA amends § 39.13 by adding the following new airworthiness directive:
The Boeing Company: Docket No. FAA-2024-1690; Project Identifier AD-2024-00083T.
(a) Comments Due Date
The FAA must receive comments on this airworthiness directive (AD) by
[INSERT DATE 45 DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL
REGISTER].
(b) Affected ADs
None.
(c) Applicability
This AD applies to all The Boeing Company Model 747-100, 747-100B, 747100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F,
747SP, and 747SR series airplanes, certificated in any category.
(d) Subject
Air Transport Association (ATA) of America Code 32, Landing gear.
(e) Unsafe Condition
This AD was prompted by a report of improper inner diameter grinding of landing
gear outer cylinders, resulting in possible heat damage to the outer cylinder of the nose
landing gear (NLG), body landing gear (BLG), and wing landing gear (WLG). The FAA
is issuing this AD to address heat damage to the outer cylinder of the NLG, BLG, and
WLG. The unsafe condition, if not addressed, could cause failure of a principal structural

element to sustain its limit load or collapse of the landing gear, which may result in loss
of control of the airplane or a runway departure.
(f) Compliance
Comply with this AD within the compliance times specified, unless already done.
(g) Required Actions
Except as specified in paragraph (h) of this AD: At the applicable times specified
in the “Compliance” paragraph of Boeing Alert Requirements Bulletin 747-32A2535 RB,
dated January 22, 2024, do all applicable actions identified in, and in accordance with,
the Accomplishment Instructions of Boeing Alert Requirements Bulletin 74732A2535 RB, dated January 22, 2024.
Note 1 to paragraph (g): Guidance for accomplishing the actions required by
this AD can be found in Boeing Alert Service Bulletin 747-32A2535, dated January 22,
2024, which is referred to in Boeing Alert Requirements Bulletin 747-32A2535 RB,
dated January 22, 2024.
(h) Exceptions to Service Information Specifications
Where the “Boeing Recommended Compliance Time” column in the table under
the “Compliance” paragraph of Boeing Alert Requirements Bulletin 747-32A2535 RB,
dated January 22, 2024, refers to “the Original Issue date of Requirements Bulletin 74732A2535 RB,” this AD requires using the effective date of this AD.
(i) Alternative Methods of Compliance (AMOCs)
(1) The Manager, AIR-520, Continued Operational Safety Branch, FAA, has the
authority to approve AMOCs for this AD, if requested using the procedures found in
14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal
inspector or responsible Flight Standards Office, as appropriate. If sending information
directly to the manager of the certification office, send it to the attention of the person

identified in paragraph (j)(1) of this AD. Information may be emailed to:
AMOC@faa.gov.
(2) Before using any approved AMOC, notify your appropriate principal
inspector, or lacking a principal inspector, the manager of the responsible Flight
Standards Office.
(3) An AMOC that provides an acceptable level of safety may be used for any
repair, modification, or alteration required by this AD if it is approved by The Boeing
Company Organization Designation Authorization (ODA) that has been authorized by the
Manager, AIR-520, Continued Operational Safety Branch, FAA, to make those findings.
To be approved, the repair method, modification deviation, or alteration deviation must
meet the certification basis of the airplane, and the approval must specifically refer to this
AD.
(j) Related Information
(1) For more information about this AD, contact Stefanie Roesli, Aviation Safety
Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; telephone 206-2313964; email stefanie.n.roesli@faa.gov.
(2) Service information identified in this AD that is not incorporated by reference
is available at the address specified in paragraph (k)(3) of this AD.
(k) Material Incorporated by Reference
(1) The Director of the Federal Register approved the incorporation by reference
of the service information listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part
51.
(2) You must use this service information as applicable to do the actions required
by this AD, unless the AD specifies otherwise.
(i) Boeing Alert Requirements Bulletin 747-32A2535 RB, dated January 22,
2024.

(ii) [Reserved]
(3) For The Boeing Company service information, contact Boeing Commercial
Airplanes, Attention: Contractual & Data Services (C&DS), 2600 Westminster
Boulevard., MC 110-SK57, Seal Beach, CA 90740-5600; telephone 562-797-1717;
website myboeingfleet.com.
(4) You may view this material at the FAA, Airworthiness Products Section,
Operational Safety Branch, 2200 South 216th Street, Des Moines, WA. For information
on the availability of this material at the FAA, call 206-231-3195.
(5) You may view this material at the National Archives and Records
Administration (NARA). For information on the availability of this material at NARA,
visit www.archives.gov/federal-register/cfr/ibr-locations or email
fr.inspection@nara.gov.
Issued on June 12, 2024.

Suzanne Masterson,
Deputy Director, Integrated Certificate Management Division,
Aircraft Certification Service.
[FR Doc. 2024-13334 Filed: 6/18/2024 8:45 am; Publication Date: 6/20/2024]