Airworthiness Directives; The Boeing Company Airplanes

[Federal Register Volume 90, Number 189 (Thursday, October 2, 2025)]
[Rules and Regulations]
[Pages 47538-47540]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-19392]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2025-1358; Project Identifier AD-2025-00620-T; 
Amendment 39-23152; AD 2025-19-12]
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 Model 737-600, -700, -700C, -800, -900, and -900ER 
series airplanes. This AD was prompted by a report of improper grinding 
of the inner diameter of the main landing gear (MLG) outer cylinders, 
resulting in possible heat damage to the outer cylinders. This AD 
requires a records check or inspection to determine if an affected 
outer cylinder is installed and replacing all affected outer cylinders. 
The FAA is issuing this AD to address the unsafe condition on these 
products.

DATES: This AD is effective November 6, 2025.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of November 6, 
2025.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2025-1358; 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:
    <bullet> For Boeing material identified in this AD, contact Boeing 
Commercial Airplanes, Attention: Contractual & Data Services (C&DS), 
2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740-5600; 
telephone 562-797-1717; website myboeingfleet.com.
    <bullet> 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-2025-1358.

[[Page 47539]]


FOR FURTHER INFORMATION CONTACT: Stefanie Roesli, Aviation Safety 
Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 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 The Boeing Company 
Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes. 
The NPRM was published in the Federal Register on July 8, 2025 (90 FR 
30027). The NPRM was prompted by a report of improper grinding of the 
inner diameter of the MLG outer cylinders, resulting in possible heat 
damage to the outer cylinders. In the NPRM, the FAA proposed to require 
a records check or inspection to determine if an affected outer 
cylinder is installed and replacing all affected outer cylinders. The 
FAA is issuing this AD to address heat damage to the MLG outer 
cylinders. The unsafe condition, if not addressed, could cause failure 
of a principal structural element to sustain its limit load or collapse 
of the MLG, which could result in loss of control of the airplane or 
runway departure.

Discussion of Final Airworthiness Directive

Comments

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

Effect of Winglets on Accomplishment of the Proposed Actions

    APB stated that the installation of winglets per Supplemental Type 
Certificate (STC) ST00830SE does not affect accomplishment of the 
actions specified in the proposed AD.
    The FAA agrees that STC ST00830SE does not affect the ability to 
accomplish the actions required by this AD. The FAA has not changed the 
AD in this regard.

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, 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 737-32A1585 RB, 
dated January 15, 2024. This material specifies procedures for 
performing a maintenance records check or an inspection of the left and 
right MLG outer cylinders to determine if any affected part numbers and 
serial numbers are installed and replacing 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 1,833 airplanes of U.S. 
registry. The FAA estimates the following costs to comply with this AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Inspection or maintenance records       2 work-hours x $85 per                $0            $170        $311,610
 check for affected parts.               hour = $170.
----------------------------------------------------------------------------------------------------------------

    The FAA estimates the following costs to do any replacement 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
----------------------------------------------------------------------------------------------------------------
                 Action                           Labor cost            Parts cost         Cost per product
----------------------------------------------------------------------------------------------------------------
Replacement of MLG outer cylinder (166    62 work-hours x $85 per           $265,000  $270,270 per MLG outer
 affected parts).                          hour = $5,270.                              cylinder.
----------------------------------------------------------------------------------------------------------------

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

[[Page 47540]]

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:

2025-19-12 The Boeing Company: Amendment 39-23152; Docket No. FAA-
2025-1358; Project Identifier AD-2025-00620-T.

(a) Effective Date

    This airworthiness directive (AD) is effective November 6, 2025.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all The Boeing Company Model 737-600, -700, -
700C, -800, -900, and -900ER 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 grinding of the 
inner diameter of the main landing gear (MLG) outer cylinders, 
resulting in possible heat damage to the outer cylinder. The FAA is 
issuing this AD to address heat damage to the MLG outer cylinders. 
The unsafe condition, if not addressed, could cause failure of a 
principal structural element to sustain its limit load or collapse 
of the MLG, which could result in loss of control of the airplane or 
runway departure.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Required Actions

    Except as specified by paragraph (h) of this AD: At the 
applicable times specified in the ``Compliance'' paragraph of Boeing 
Alert Requirements Bulletin 737-32A1585 RB, dated January 15, 2024, 
do all applicable actions identified in, and in accordance with, the 
Accomplishment Instructions of Boeing Alert Requirements Bulletin 
737-32A1585 RB, dated January 15, 2024.
    Note 1 to paragraph (g): Guidance for accomplishing the actions 
required by this AD can be found in Boeing Alert Service Bulletin 
737-32A1585, dated January 15, 2024, which is referred to in Boeing 
Alert Requirements Bulletin 737-32A1585 RB, dated January 15, 2024.

(h) Exception to Requirements Bulletin Specifications

    Where the ``Boeing Recommended Compliance Time'' column in the 
table under the ``Compliance'' paragraph of Boeing Alert 
Requirements Bulletin 737-32A1585 RB, dated January 15, 2024, refers 
to the original issue date of Boeing Alert Requirements Bulletin 
737-32A1585 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: [email protected]. 
Before using any approved AMOC, notify your appropriate principal 
inspector, or lacking a principal inspector, the manager of the 
responsible Flight Standards Office.
    (2) 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 St., Des Moines, WA 
98198; phone: 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) 
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 737-32A1585 RB, dated 
January 15, 2024.
    (ii) [Reserved]
    (3) For Boeing material identified in this AD, contact Boeing 
Commercial Airplanes, Attention: Contractual & Data Services (C&DS), 
2600 Westminster Blvd., 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 St., 
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 [email protected].

    Issued on September 19, 2025.
Peter A. White,
Deputy Director, Integrated Certificate Management Division, Aircraft 
Certification Service.
[FR Doc. 2025-19392 Filed 10-1-25; 8:45 am]
BILLING CODE 4910-13-P

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