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[Federal Register Volume 90, Number 26 (Monday, February 10, 2025)]
[Rules and Regulations]
[Pages 9201-9203]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-02398]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-1690; Project Identifier AD-2024-00083-T; 
Amendment 39-22938; AD 2025-02-05]
RIN 2120-AA64

Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all 
The Boeing Company (Boeing) Model 747-100, 747-100B, 747-100B SUD, 747-
200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, 747SP, 
and 747SR series airplanes. 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). This AD requires replacing any affected outer cylinders. The FAA 
is issuing this AD to address the unsafe condition on these products.

DATES: This AD is effective March 17, 2025.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of March 17, 
2025.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2024-1690; 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 final rule, any comments received, and other 
information. The address for Docket Operations is U.S. Department of 
Transportation, Docket Operations, M-30, West Building Ground Floor, 
Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.
    Material Incorporated by Reference:
     For The Boeing Company material identified in this AD, 
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 material at the FAA, Airworthiness 
Products Section, Operational Safety Branch, 2200 South 216th St., 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 under 
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 [email protected].

SUPPLEMENTARY INFORMATION: 

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 by adding an AD that would apply to all Boeing Model 747-
100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 
747-400, 747-400D, 747-400F, 747SP, and 747SR series airplanes. The 
NPRM published in the Federal Register on June 20, 2024 (89 FR 51861). 
The NPRM 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 NLG, BLG, and WLG. In the NPRM, the FAA 
proposed to require replacing any affected outer cylinders. The FAA is 
issuing this AD to address the unsafe condition on these products.

Discussion of Final Airworthiness Directive

Comments

    The FAA received one comment from The Air Line Pilots Association, 
International (ALPA) who supported the NPRM without change.
    The FAA received two additional comments from Boeing. The following 
presents the comments received on the NPRM and the FAA's response to 
each comment.

Request To Clarify Affected Outer Cylinder Serial Numbers

    Boeing requested that an exception paragraph be added to clarify 
affected outer cylinder numbers. Boeing stated Boeing Alert 
Requirements Bulletin 747-32A2535 RB, dated January 22, 2024, 
inadvertently lists nine serial numbers without the correct number of 
leading zeros. Boeing requested that the FAA add the following language 
to paragraph (h) of the proposed AD, ``Where Appendix B of Boeing Alert 
Requirements Bulletin 747-32A2535 RB, Original Issue dated January 22, 
2024, specifies two-digit serial numbers, add two leading zeros (e.g., 
serial number 47 should be 0047). Where Appendix B of Boeing Alert 
Requirements Bulletin 747-32A2535 RB, Original Issue dated January 22, 
2024, specifies three-digit serial numbers, add one leading zero (e.g., 
serial number 109 should be 0109).''
    The FAA concurs with the comment. The serial numbers listed in 
Appendix B of Boeing Alert Requirements Bulletin 747-32A2535 RB, dated 
January 22, 2024, are part of the required action to find the parts 
affected by the unsafe condition. Furthermore, the two-digit and three-
digit serial numbers listed in Appendix B of Boeing Alert Requirements 
Bulletin 747-32A2535 RB, dated January 22, 2024, do not exist and the 
request is for clarification only. The FAA has revised this AD 
accordingly.

Request To Add a Parts Installation Prohibition

    Boeing requested that a parts installation prohibition paragraph be 
added to the proposed AD. Boeing stated the outer cylinders of the NLG, 
BLG, and WLG are rotable structural components which may be moved from 
one airplane to another. Boeing stated the applicability of the AD 
covers all in-service Model 747 airplanes noted in Boeing Alert 
Requirements Bulletin 747-32A2535 RB, dated January 22, 2024; however 
the parts installation

[[Page 9202]]

prohibition is needed to prevent the affected outer cylinders from 
being moved onto airplanes which have already complied with the 
required actions of the AD.
    The FAA agrees to clarify. 14 CFR 39.7 specifies that once an AD is 
issued, no person may operate a product to which the AD applies except 
in accordance with the requirements of that AD. Further, 14 CFR 39.9 
imposes a continuing obligation to maintain compliance with an AD by 
establishing a separate violation for each time an aircraft is operated 
that fails to meet AD requirements. Thus, operators have an ongoing 
obligation to ensure that the AD-mandated configuration is maintained. 
The FAA has not changed this AD as a result of the request.

Conclusion

    The FAA reviewed the relevant data, considered any comments 
received, and determined that air safety requires adopting this AD as 
proposed. Accordingly, the FAA is issuing this AD to address the unsafe 
condition on these products. Except for minor editorial changes, and 
any other changes described previously, this AD is adopted as proposed 
in the NPRM. None of the changes will increase the economic burden on 
any operator.

Material Incorporated by Reference Under 1 CFR Part 51

    The FAA reviewed Boeing Alert Requirements Bulletin 747-32A2535 RB, 
dated January 22, 2024. This material specifies procedures for 
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 material is reasonably available because the interested 
parties have access to it through their normal course of business or by 
the means identified in the ADDRESSES section.

Costs of Compliance

    The FAA estimates that this AD affects 168 airplanes of U.S. 
registry. The FAA estimates the following costs to comply with this AD:

                                                 Estimated Costs
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                                                                                     Cost per      Cost on U.S.
                 Action                          Labor cost           Parts cost      product       operators
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Inspection or maintenance records check  3 work-hours x $85 per               $0          $255          $42,840
 for affected parts.                      hour = $255.
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    The FAA estimates the following costs to do any replacements that 
would be required based on the results of the inspection or maintenance 
records check. The agency has no way of determining the number of 
airplanes that might need this replacement:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                              Cost per
               Action                       Labor cost         Parts cost      product    Cost on U.S. operators
----------------------------------------------------------------------------------------------------------------
Replacement of outer cylinder (67     161 work-hours x $85       $325,000      $338,685   $22,691,895 (67
 affected parts).                      per hour = $13,685.                                 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

    This AD will not have federalism implications under Executive Order 
13132. This AD will 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 that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Will not affect intrastate aviation in Alaska, and
    (3) 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.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

The Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive:

2025-02-05 The Boeing Company: Amendment 39-22938; Docket No. FAA-
2024-1690; Project Identifier AD-2024-00083-T.

 (a) Effective Date

    This airworthiness directive (AD) is effective March 17, 2025.

[[Page 9203]]

 (b) Affected ADs

    None.

 (c) Applicability

    This AD applies to all The Boeing Company Model 747-100, 747-
100B, 747-100B 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 
747-32A2535 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 Requirements Bulletin Specifications

    (1) 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 747-32A2535 
RB,'' this AD requires using the effective date of this AD.
    (2) Where Appendix B of Boeing Alert Requirements Bulletin 747-
32A2535 RB, dated January 22, 2024, specifies two-digit serial 
numbers, add two leading zeros (e.g., serial number 47 should be 
0047).
    (3) Where Appendix B of Boeing Alert Requirements Bulletin 747-
32A2535 RB, dated January 22, 2024, specifies three-digit serial 
numbers, add one leading zero (e.g., serial number 109 should be 
0109).

 (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: [email protected].
    (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 206-231-3964; email [email protected].
    (2) Material 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 material listed in this paragraph 
under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this material 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 material identified in this AD, 
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 protected].

    Issued on January 16, 2025.
Suzanne Masterson,
Deputy Director, Integrated Certificate Management Division, Aircraft 
Certification Service.
[FR Doc. 2025-02398 Filed 2-7-25; 8:45 am]
BILLING CODE 4910-13-P
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