Rule2026-19082
Airworthiness Directives; The Boeing Company Airplanes
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
September 17, 2026
Effective
October 22, 2026
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA is adopting a new airworthiness directive (AD) for certain The Boeing Company Model 737-8, 737-9, and 737-8200 airplanes. This AD was prompted by reports indicating cracks in the bear strap and stub frame at the forward galley door cutout. This AD requires inspections for existing repairs; an inspection for any crack of the fuselage skin, bear strap, and stub frame; repetitive inspections for any crack of the bear strap and stub frame; and applicable on-condition actions. The FAA is issuing this AD to address the unsafe condition on these products.
Full Text
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<title>Federal Register, Volume 91 Issue 179 (Thursday, September 17, 2026)</title>
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[Federal Register Volume 91, Number 179 (Thursday, September 17, 2026)]
[Rules and Regulations]
[Pages 58809-58812]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-19082]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2025-3439; Project Identifier AD-2025-00463-T;
Amendment 39-23462; AD 2026-18-07]
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
certain The Boeing Company Model 737-8, 737-9, and 737-8200 airplanes.
This AD was prompted by reports indicating cracks in the bear strap and
stub frame at the forward galley door cutout. This AD requires
inspections for existing repairs; an inspection for any crack of the
fuselage skin, bear strap, and stub frame; repetitive inspections for
any crack of the bear strap and stub frame; and applicable on-condition
actions. The FAA is issuing this AD to address the unsafe condition on
these products.
DATES: This AD is effective October 22, 2026.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of October 22,
2026.
ADDRESSES:
AD Docket: You may examine the AD docket at <a href="http://regulations.gov">regulations.gov</a> under
Docket No. FAA-2025-3439; 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 <a href="http://myboeingfleet.com">myboeingfleet.com</a>.
<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 <a href="http://regulations.gov">regulations.gov</a> under
Docket No. FAA-2025-3439.
[[Page 58810]]
FOR FURTHER INFORMATION CONTACT: Luis Cortez-Muniz, Aviation Safety
Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 206-
231-3958; email: <a href="/cdn-cgi/l/email-protection#c0acb5a9b3eea1eea3afb2b4a5baedadb5aea9ba80a6a1a1eea7afb6"><span class="__cf_email__" data-cfemail="8ae6ffe3f9a4eba4e9e5f8feeff0a7e7ffe4e3f0caecebeba4ede5fc">[email protected]</span></a>.
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 certain Boeing Model
737-8, 737-9, and 737-8200 airplanes. The NPRM was published in the
Federal Register on November 25, 2025 (90 FR 53243). The NPRM was
prompted by reports indicating that cracking was found in the bear
strap and stub frame at the forward galley door cutout, from station
(STA) 290 to STA 296 and between stringer S-8R and stringer S-9R. In
the NPRM, the FAA proposed to require inspections for existing repairs;
an inspection for any crack of the fuselage skin, bear strap, and stub
frame; repetitive inspections for any crack of the bear strap and stub
frame; and applicable on-condition actions. The FAA is issuing this AD
to address any crack in the fuselage skin, bear strap, and stub frame
at the forward galley door cutout from STA 290 to STA 296 and between
stringer S-8R and stringer S-9R, before it reaches critical length. The
unsafe condition, if not addressed, may result in the inability of a
principal structural element to sustain limit load, which could
adversely affect the structural integrity of the airplane.
Discussion of Final Airworthiness Directive
Comments
The FAA received comments from four commenters, including Boeing,
The Foundation for Aviation Safety, Southwest Airlines (Southwest), and
United Airlines (United). The following presents the comments received
on the NPRM and the FAA's response to each comment.
Request To Explain How the Root Cause Is Addressed
The Foundation for Aviation Safety asked what the FAA and Boeing
are doing to address the root cause of the defect. The commenter also
asked if a structural defect is important enough to immediately ground
an airplane after it is detected, why is the inspection for defects not
accomplished long before the proposed compliance time.
The FAA is issuing this AD to address the unsafe condition on in-
service airplanes. The required compliance times for the initial
inspection and on-condition repetitive inspections and repair were
established to ensure any crack is detected and repaired before the
crack reaches critical length with multiple opportunities for
detection. The rulemaking timeline was based on Boeing 737 fleet
findings, supporting analysis, and the severity of the effect on the
airplane (i.e., safety consequences) if cracking propagates beyond a
critical length. The FAA determined that the required actions and
compliance times provide an acceptable level of safety. In addition,
Boeing is introducing changes to the manufacturing process that address
the root cause of the unsafe condition on in-production airplanes. The
FAA did not change this AD as a result of this comment.
Request To Correct Typographical Error in Requirements Bulletin
Boeing, Southwest, and United requested that flag note (a) of
Figure 6 in Boeing Alert Requirements Bulletin 737-53A1420 RB, dated
February 13, 2025, be corrected to refer to inspection of the stub
frame instead of inspection of the bear strap. The commenters noted
that there is a typographical error which states ``bear strap'' instead
of ``stub frame'' in flag note (a) of Figure 6 and requested the FAA
revise the proposed AD to add an exception to correct the error.
The FAA agrees. The FAA has added an exception in paragraph (h)(3)
of this AD accordingly.
Request To Use Later Approved Revisions of Referenced Drawings
United requested to use later approved revisions of the drawings
referenced in the Work Instructions, Table 1, footnote (c) of Boeing
Alert Requirements Bulletin 737-53A1420 RB, dated February 13, 2025,
without obtaining an alternative method of compliance (AMOC). United
noted that the Picture Sheet Data List (PSDL) referenced in the work
instructions direct operators to use Boeing PSDL 141A8370 revision C
and Boeing Module Parts List (MPL) 141A8370-11. United noted that this
approach restricts operators from utilizing the most current, FAA-
approved revisions of the applicable PSDL and MPL data that may be
effective for the aircraft configuration.
The FAA disagrees. The FAA may not refer to any document that does
not yet exist in an AD. The specific drawing revisions are required as
they include prescriptive instructions for the stub frame replacement
when damage is found common to the stub frame. To ensure the
configuration maintains an acceptable level of safety, the service
information does not currently allow for later approved revisions.
However, if later approved revisions of the drawings provide an
acceptable level of safety, operators may request approval of an AMOC
under the provisions of paragraph (i) of this AD. The FAA did not
change this AD as a result of this comment.
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 737-53A1420 RB,
dated February 13, 2025. This material specifies procedures for doing
Option 1 or Option 2 actions as specified below, and applicable on-
condition actions. On-condition actions include replacing the stub
frame, doing alternative inspections, and doing a repair.
<bullet> Option 1--Perform initial external general visual
inspection (GVI) of the fuselage skin and gap cover for any repair,
initial internal GVI of the bear strap and stub frame for any repair,
and repetitive internal high frequency eddy current (HFEC) inspections
of the bear strap and stub frame for any crack.
<bullet> Option 2--Perform initial external GVI of the fuselage
skin and gap cover for any repair, initial internal GVI of the stub
frame for any repair, initial external HFEC inspection of the fuselage
skin for any crack, initial external low frequency eddy current (LFEC)
inspection of the bear strap for any crack, initial internal HFEC
inspection of the stub frame for any crack, and repetitive internal
HFEC inspections of the bear strap and stub frame for any crack.
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 476 airplanes of U.S.
registry. The FAA estimates the following costs to comply with this AD:
[[Page 58811]]
Estimated Costs
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Cost on U.S.
Action Labor cost Parts cost Cost per product operators
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Option 1--Initial inspections... 31 work-hours x $85 per $0 $2,635............. $1,254,260.
hour = $2,635.
Option 2--Initial inspections... 7 work-hours x $85 per 0 $595............... $283,220.
hour = $595.
Repetitive internal HFEC 29 work-hours x $85 per 0 $2,465 per $1,173,340 per
inspections of the bear strap hour = $2,465 per inspection cycle. inspection cycle.
and stub frame per Option 1 or inspection cycle.
Option 2.
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The FAA estimates the following costs to do any necessary
replacements that would be required based on the results of the
inspection. The agency has no way of determining the number of aircraft
that might need this replacement:
On-Condition Costs
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Cost per
Action Labor cost Parts cost product
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Replace the stub frame..................... 35 work-hours x $85 per hour = $1,359 $4,334
$2,975.
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The FAA has received no definitive data that would enable the
agency to provide cost estimates for the on-condition repairs specified
in this AD.
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:
2026-18-07 The Boeing Company: Amendment 39-23462; Docket No. FAA-
2025-3439; Project Identifier AD-2025-00463-T.
(a) Effective Date
This airworthiness directive (AD) is effective October 22, 2026.
(b) Affected ADs
None.
(c) Applicability
This AD applies to The Boeing Company Model 737-8, 737-9, and
737-8200 airplanes, certificated in any category, as identified in
Boeing Alert Requirements Bulletin 737-53A1420 RB, dated February
13, 2025.
(d) Subject
Air Transport Association (ATA) of America Code 53, Fuselage.
(e) Unsafe Condition
This AD was prompted by reports indicating cracks in the bear
strap and stub frame at the forward galley door cutout, from station
(STA) 290 to STA 296 and between stringer S-8R and stringer S-9R.
The FAA is issuing this AD to address any crack in the fuselage
skin, bear strap, and stub frame at the forward galley door cutout
from STA 290 to STA 296 and between stringer S-8R and stringer S-9R,
before it reaches critical length. The unsafe condition, if not
addressed, may result in the inability of a principal structural
element to sustain limit load, which could adversely affect the
structural integrity of the airplane.
(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 737-53A1420 RB, dated February 13, 2025,
do all applicable actions identified in, and in accordance with, the
Accomplishment Instructions of Boeing Alert Requirements Bulletin
737-53A1420 RB, dated February 13, 2025.
Note 1 to paragraph (g): Guidance for accomplishing the actions
required by this AD can be found in Boeing Alert Service Bulletin
737-53A1420, dated February 13, 2025, which is referred to in Boeing
Alert Requirements Bulletin 737-53A1420 RB, dated February 13, 2025.
(h) Exceptions to Requirements Bulletin Specifications
(1) Where the Compliance Time columns of the tables in the
``Compliance'' paragraph of Boeing Alert Requirements Bulletin 737-
53A1420 RB, dated February 13, 2025, refer to the original issue
date of Requirements Bulletin 737-53A1420 RB, this AD requires using
the effective date of this AD.
(2) Where Boeing Alert Requirements Bulletin 737-53A1420 RB,
dated February 13, 2025, specifies contacting Boeing for repair
instructions or for alternative
[[Page 58812]]
inspections: This AD requires doing the repair, or doing the
alternative inspections and applicable on-condition actions using a
method approved in accordance with the procedures specified in
paragraph (i) of this AD.
(3) Where flag note (a) of Figure 6 of the Accomplishment
Instructions of Boeing Alert Requirements Bulletin 737-53A1420 RB,
dated February 13, 2025, specifies ``Use the probe to scan internal
surface of the bear strap at the specified area'', this AD requires
replacing that text with ``Use the probe to scan the internal
surface of the stub frame at the specified area''.
(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 Continued Operational
Safety Branch, send it to the attention of the person identified in
paragraph (j)(1) of this AD. Information may be emailed to:
<a href="/cdn-cgi/l/email-protection#7f3e32303c3f191e1e51181009"><span class="__cf_email__" data-cfemail="22636f6d61624443430c454d54">[email protected]</span></a>. 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) Additional Information
(1) For more information about this AD, contact Luis Cortez-
Muniz, Aviation Safety Engineer, FAA, 2200 South 216th St., Des
Moines, WA 98198; phone: 206-231-3958; email: <a href="/cdn-cgi/l/email-protection#fc9089958fd29dd29f938e889986d19189929586bc9a9d9dd29b938a"><span class="__cf_email__" data-cfemail="412d3428326f206f222e3335243b6c2c342f283b012720206f262e37">[email protected]</span></a>.
(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 737-53A1420 RB, dated
February 13, 2025.
(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 <a href="http://myboeingfleet.com">myboeingfleet.com</a>.
(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 <a href="http://www.archives.gov/federal-register/cfr/ibr-locations">www.archives.gov/federal-register/cfr/ibr-locations</a> or email <a href="/cdn-cgi/l/email-protection#7412065a1d1a07041117001d1b1a341a1506155a131b02"><span class="__cf_email__" data-cfemail="82e4f0acebecf1f2e7e1f6ebedecc2ece3f0e3ace5edf4">[email protected]</span></a>.
Issued on September 2, 2026.
Brian Knaup,
Acting Deputy Director, Integrated Certificate Management Division,
Aircraft Certification Service.
[FR Doc. 2026-19082 Filed 9-16-26; 8:45 am]
BILLING CODE 4910-13-P
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