Proposed Rule2026-11472
Airworthiness Directives; The Boeing Company Airplanes
Primary source
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Published
June 8, 2026
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA proposes to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 747-8 series airplanes. This proposed AD was prompted by a report of cracks in the fuselage skin lap splice at the upper fastener row between certain stations at certain stringers. This proposed AD would require performing repetitive external surface high frequency eddy current (HFEC) inspections of the upper fastener row of the fuselage skin lap splice for any crack and applicable on-condition actions. The FAA is proposing this AD to address the unsafe condition on these products.
Full Text
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<title>Federal Register, Volume 91 Issue 109 (Monday, June 8, 2026)</title>
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[Federal Register Volume 91, Number 109 (Monday, June 8, 2026)]
[Proposed Rules]
[Pages 34583-34585]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-11472]
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Proposed Rules
Federal Register
________________________________________________________________________
This section of the FEDERAL REGISTER contains notices to the public of
the proposed issuance of rules and regulations. The purpose of these
notices is to give interested persons an opportunity to participate in
the rule making prior to the adoption of the final rules.
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Federal Register / Vol. 91, No. 109 / Monday, June 8, 2026 / Proposed
Rules
[[Page 34583]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2026-4653; Project Identifier AD-2025-01875-T]
RIN 2120-AA64
Airworthiness Directives; The Boeing Company Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for certain The Boeing Company Model 747-8 series airplanes. This
proposed AD was prompted by a report of cracks in the fuselage skin lap
splice at the upper fastener row between certain stations at certain
stringers. This proposed AD would require performing repetitive
external surface high frequency eddy current (HFEC) inspections of the
upper fastener row of the fuselage skin lap splice for any crack and
applicable on-condition actions. 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 July 23,
2026.
ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:
<bullet> Federal eRulemaking Portal: Go to <a href="http://regulations.gov">regulations.gov</a>. Follow
the instructions for submitting comments.
<bullet> Fax: 202-493-2251.
<bullet> 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.
<bullet> 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 <a href="http://regulations.gov">regulations.gov</a> under
Docket No. FAA-2026-4653; 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:
<bullet> For Boeing material identified in this proposed 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-2026-4653.
FOR FURTHER INFORMATION CONTACT: Stefanie Roesli, Aviation Safety
Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 206-
231-3964; email: <a href="/cdn-cgi/l/email-protection#5f2c2b3a393e31363a7131712d303a2c33361f393e3e71383029"><span class="__cf_email__" data-cfemail="e192958487808f8884cf8fcf938e84928d88a1878080cf868e97">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION:
Comments Invited
The FAA invites you to send any written relevant data, views, or
arguments about this proposal. Send your comments using a method listed
under the ADDRESSES section. Include ``Docket No. FAA-2026-4653;
Project Identifier AD-2025-01875-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
<a href="http://regulations.gov">regulations.gov</a>, 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 St.,
Des Moines, WA 98198; phone: 206-231-3964; email:
<a href="/cdn-cgi/l/email-protection#671413020106090e02490949150802140b0e2701060649000811"><span class="__cf_email__" data-cfemail="dcafa8b9babdb2b5b9f2b2f2aeb3b9afb0b59cbabdbdf2bbb3aa">[email protected]</span></a>. Any commentary that the FAA receives that is
not specifically designated as CBI will be placed in the public docket
for this rulemaking.
Background
Fatigue damage can occur locally, in small areas or structural
design details, or globally, in widespread areas. Multiple-site damage
is widespread damage that occurs in a large structural element such as
a single rivet line of a lap splice joining two large skin panels.
Widespread damage can also occur in multiple elements such as adjacent
frames or stringers. Multiple-site damage and multiple-element damage
cracks are typically too small initially to be reliably detected with
normal inspection methods. Without intervention, these cracks will grow
and eventually compromise the structural integrity of the airplane.
This condition is known as widespread fatigue damage (WFD). It is
associated with general degradation of large areas of structure with
similar structural details and stress levels. As an airplane ages, WFD
will likely occur, and will certainly occur if the airplane is operated
long enough without any intervention.
An FAA final rule (``Aging Airplane Program: Widespread Fatigue
Damage;'' 75 FR 69746, November 15, 2010) became effective on January
14, 2011, and amended 14 CFR parts 25, 26, 121,
[[Page 34584]]
and 129 (commonly known as the WFD rule). The WFD rule requires certain
actions to prevent structural failure due to WFD throughout the
operational life of certain existing transport category airplanes and
all of these airplanes that will be certificated in the future. Design
approval holders (DAHs) of existing and future airplanes subject to the
WFD rule are required to establish a limit of validity (LOV) of the
engineering data that support the structural maintenance program.
Operators affected by the WFD rule may not fly an airplane beyond its
LOV, unless an extended LOV is approved.
The WFD rule does not require identifying and developing
maintenance actions if the DAHs can show that such actions are not
necessary to prevent WFD before the airplane reaches the LOV. Many
LOVs, however, do depend on accomplishment of future maintenance
actions. As stated in the WFD rule, any maintenance actions necessary
to reach the LOV will be mandated by airworthiness directives through
separate rulemaking actions.
In the context of WFD, this action is necessary to enable DAHs to
propose LOVs that allow operators the longest operational lives for
their airplanes, and still ensure that WFD will not occur. This
approach allows for an implementation strategy that provides
flexibility to DAHs in determining the timing of service information
development (with FAA approval), while providing operators with
certainty regarding the LOV applicable to their airplanes.
The FAA has received a report of cracks at eight fastener hole
locations in the fuselage skin lap splice between station (STA) 1450
and STA 1470 at stringers S-23L and S-23R on a Boeing Model 747-400
series airplane. After this report was received, Boeing did an HFEC
inspection on the Boeing Model 747-100 fatigue test airplane and found
cracks on the countersink area of the fastener holes on the lap splice
between STA 1416 and STA 1480 at stringers S-23L and S-23R. The FAA
issued AD 2024-19-01, Amendment 39-22843 (89 FR 82486, October 11,
2024) to address the unsafe condition on 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. No cracks have
been reported on the Model 747-8 series airplanes; however, the Model
747-8 series airplanes and the Model 747-400 series airplanes have
similar lap splice design and fatigue stresses. Therefore, the FAA has
determined that Model 747-8 series airplanes may also be subject to the
identified unsafe condition. This condition, if not addressed, could
result in possible rapid decompression and loss of structural integrity
of the airplane.
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.
Material Incorporated by Reference Under 1 CFR Part 51
The FAA reviewed Boeing Alert Requirements Bulletin 747-53A2913 RB,
dated December 19, 2025. This material specifies procedures for
performing repetitive external surface HFEC inspections of the upper
fastener row of the fuselage skin lap splice between STA 1350 and STA
1480 at stringers S-23L and S-23R for any crack and applicable on-
condition actions. On-condition actions include contacting Boeing for
repair instructions and doing the repair.
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.
Proposed AD Requirements in This NPRM
This proposed AD would require accomplishing the actions specified
in the material 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 material
at <a href="http://regulations.gov">regulations.gov</a> under Docket No. FAA-2026-4653.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect 3 airplanes of U.S. registry. The FAA estimates the following
costs to comply with this proposed AD:
Estimated Costs
----------------------------------------------------------------------------------------------------------------
Parts Cost on U.S.
Action Labor cost cost Cost per product operators
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HFEC inspection................... 8 work-hours x $85 $0 $680 per inspection $2,040 per
per hour = $680 per cycle. inspection cycle.
inspection cycle.
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The FAA has received no definitive data on which to base the cost
estimates for the on-condition repairs specified in this proposed 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
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.
[[Page 34585]]
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
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:
The Boeing Company: Docket No. FAA-2026-4653; Project Identifier AD-
2025-01875-T.
(a) Comments Due Date
The FAA must receive comments on this airworthiness directive
(AD) by July 23, 2026.
(b) Affected ADs
None.
(c) Applicability
This AD applies to The Boeing Company Model 747-8 series
airplanes, certificated in any category, as identified in Boeing
Alert Requirements Bulletin 747-53A2913 RB, dated December 19, 2025.
(d) Subject
Air Transport Association (ATA) of America Code 53, Fuselage.
(e) Unsafe Condition
This AD was prompted by a report of cracks in the fuselage skin
lap splice at the upper fastener row between certain stations at
certain stringers. The FAA is issuing this AD to address cracks in
the fuselage skin lap splice. The unsafe condition, if not
addressed, could result in possible rapid decompression and loss of
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 by paragraph (h) of this AD: At the
applicable times specified in the ``Compliance'' paragraph of Boeing
Alert Requirements Bulletin 747-53A2913 RB, dated December 19, 2025,
do all applicable actions identified in, and in accordance with, the
Accomplishment Instructions of Boeing Alert Requirements Bulletin
747-53A2913 RB, dated December 19, 2025.
Note 1 to paragraph (g): Guidance for accomplishing the actions
required by this AD can be found in Boeing Alert Service Bulletin
747-53A2913, dated December 19, 2025, which is referred to in Boeing
Alert Requirements Bulletin 747-53A2913 RB, dated December 19, 2025.
(h) Exceptions to Requirements Bulletin Specifications
Where Boeing Alert Requirements Bulletin 747-53A2913 RB, dated
December 19, 2025, specifies contacting Boeing for repair
instructions: This AD requires doing the repair and applicable on-
condition actions using a method approved in accordance with the
procedures specified in paragraph (i) 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 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#6e2f23212d2e080f0f40090118"><span class="__cf_email__" data-cfemail="80c1cdcfc3c0e6e1e1aee7eff6">[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 Stefanie Roesli,
Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA
98198; phone: 206-231-3964; email: <a href="/cdn-cgi/l/email-protection#4c3f38292a2d2225296222623e23293f20250c2a2d2d622b233a"><span class="__cf_email__" data-cfemail="a1d2d5c4c7c0cfc8c48fcf8fd3cec4d2cdc8e1c7c0c08fc6ced7">[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 747-53A2913 RB, dated
December 19, 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#1573673b7c7b66657076617c7a7b557b7467743b727a63"><span class="__cf_email__" data-cfemail="a4c2d68acdcad7d4c1c7d0cdcbcae4cac5d6c58ac3cbd2">[email protected]</span></a>.
Issued on June 4, 2026.
Brian Knaup,
Acting Deputy Director, Integrated Certificate Management Division,
Aircraft Certification Service.
[FR Doc. 2026-11472 Filed 6-5-26; 8:45 am]
BILLING CODE 4910-13-P
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