Proposed Rule2026-06471
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
April 2, 2026
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA proposes to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 757-200 series airplanes. This proposed AD was prompted by a report of a crack found in the frame during a structural inspection of an airplane equipped with an Air Cargo Equipment (ACE) cargo loading system in the forward cargo bay. This proposed AD would require an inspection or maintenance records check of certain frames for any repair and applicable on-condition actions, and a repetitive high frequency eddy current (HFEC) surface inspection of certain frames 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 63 (Thursday, April 2, 2026)</title>
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[Federal Register Volume 91, Number 63 (Thursday, April 2, 2026)]
[Proposed Rules]
[Pages 16590-16593]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-06471]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2026-3469; Project Identifier AD-2025-01573-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 757-200 series airplanes. This
proposed AD was prompted by a report of a crack found in the frame
during a structural inspection of an airplane equipped with an Air
Cargo Equipment (ACE) cargo loading system in the forward cargo bay.
This proposed AD would require an inspection or maintenance records
check of certain frames for any repair and applicable on-condition
actions, and a repetitive high frequency eddy current (HFEC) surface
inspection of certain frames 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 May 18,
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-2026-3469; 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-2026-3469.
FOR FURTHER INFORMATION CONTACT: Wayne Ha, Aviation Safety Engineer,
FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 562-627-5238;
email: <a href="/cdn-cgi/l/email-protection#2d5a4c54434803454c6d4b4c4c034a425b"><span class="__cf_email__" data-cfemail="88ffe9f1e6eda6e0e9c8eee9e9a6efe7fe">[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-2026-3469;
Project Identifier AD-2025-01573-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
[[Page 16591]]
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 Wayne
Ha, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA
98198; phone: 562-627-5238; email: <a href="/cdn-cgi/l/email-protection#4334223a2d266d2b22032522226d242c35"><span class="__cf_email__" data-cfemail="3a4d5b43545f14525b7a5c5b5b145d554c">[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 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, 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 indicating that a crack was found on
a Model 757-200 airplane equipped with an ACE cargo loading system in
the forward cargo bay. The crack was found in the frame at station
(STA) 740, between stringers S-21R and S-22R, during a structural
inspection in a heavy maintenance check. The crack proceeded from a
fastener hole common to the STA 740 frame inner chord at the support
channel reinforcement for the ACE cargo loading system. The FAA has
determined that the crack is likely the result of high operating frame
stress, together with a frame inner chord hard point fatigue detail,
common to the reinforcing channel associated with the ACE cargo loader
configuration. This safety condition exists when the ACE cargo loading
provisions have been installed independent of the cargo loading module
being installed. In addition, analysis has shown that although the ACE
cargo loading provisions can be installed at many frame locations in
the lower lobe, vulnerability to undetected cracking is limited to the
highly loaded frames between STA 640 and STA 840. Existing maintenance
planning document inspections do not provide sufficient inspections to
maintain the safety of the fleet for known cracks. This condition, if
not addressed, could result in the inability of the frame inner chord,
a principal structural element, to sustain limit load, which could
adversely affect the 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 757-53A0128 RB,
dated September 17, 2025. This material specifies procedures for
performing a general visual inspection (GVI) or maintenance records
check of the frames from STA 640 to STA 840, between stringers S-21L
and S-23L, and S-21R and S-23R for any repair and applicable on-
condition actions. On-condition actions include contacting Boeing for
alternative inspection and doing the alternative inspection and
applicable corrective actions in the repaired areas.
This material also specifies procedures for a repetitive high
frequency eddy current (HFEC) surface inspection of the frames from STA
640 to STA 840, between stringers S-21L and S-23L, and S-21R and S-23R
for any crack and applicable on-condition actions. On-condition actions
include contacting Boeing for repair instructions and doing the repair.
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.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect 122 airplanes of U.S. registry. The FAA estimates the following
costs to comply with this proposed AD:
[[Page 16592]]
Estimated Costs
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Cost on U.S.
Action Labor cost Parts cost Cost per product operators
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General visual inspection or Up to 22 work-hours $0 Up to $1,870........ Up to $228,140.
maintenance records check. x $85 per hour =
$1,870.
HFEC inspection.................. 8 work-hours x $85 = 0 $680 per inspection $82,960 per
$680 per inspection cycle. inspection cycle.
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.
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-2026-3469; Project Identifier AD-
2025-01573-T.
(a) Comments Due Date
The FAA must receive comments on this airworthiness directive
(AD) by May 18, 2026.
(b) Affected ADs
None.
(c) Applicability
This AD applies to The Boeing Company Model 757-200 series
airplanes, certificated in any category, as identified in Boeing
Alert Requirements Bulletin 757-53A0128 RB, dated September 17,
2025.
(d) Subject
Air Transport Association (ATA) of America Code 53, Fuselage.
(e) Unsafe Condition
This AD was prompted by a report of a crack found in the frame
during a structural inspection of an airplane equipped with an Air
Cargo Equipment (ACE) cargo loading system in the forward cargo bay.
The FAA is issuing this AD to address any crack in the frames from
station (STA) 640 to STA 840, between certain stringers. The unsafe
condition, if not addressed, could result in the inability of the
frame inner chord, 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 by paragraph (h) of this AD: At the
applicable times specified in the ``Compliance'' paragraph of Boeing
Alert Requirements Bulletin 757-53A0128 RB, dated September 17,
2025, do all applicable actions identified in, and in accordance
with, the Accomplishment Instructions of Boeing Alert Requirements
Bulletin 757-53A0128 RB, dated September 17, 2025.
Note 1 to paragraph (g): Guidance for accomplishing the actions
required by this AD can be found in Boeing Alert Service Bulletin
757-53A0128, dated September 17, 2025, which is referred to in
Boeing Alert Requirements Bulletin 757-53A0128 RB, dated September
17, 2025.
(h) Exceptions to Requirements Bulletin Specifications
(1) Where the Condition and Compliance Time columns of the
tables in the ``Compliance'' paragraph of Boeing Alert Requirements
Bulletin 757-53A0128 RB, dated September 17, 2025, refer to the
original issue date of Requirements Bulletin 757-53A0128 RB, this AD
requires using the effective date of this AD.
(2) Where Boeing Alert Requirements Bulletin 757-53A0128 RB,
dated September 17, 2025, specifies contacting Boeing for repair
instructions or for alternative 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.
(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) of this AD. Information may be emailed to:
<a href="/cdn-cgi/l/email-protection#afeee2e0ecefc9cece81c8c0d9"><span class="__cf_email__" data-cfemail="3c7d71737f7c5a5d5d125b534a">[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.
[[Page 16593]]
(j) Additional Information
For more information about this AD, contact Wayne Ha, Aviation
Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198;
phone: 562-627-5238; email: <a href="/cdn-cgi/l/email-protection#e592849c8b80cb8d84a5838484cb828a93"><span class="__cf_email__" data-cfemail="b9ced8c0d7dc97d1d8f9dfd8d897ded6cf">[email protected]</span></a>.
(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 757-53A0128 RB, dated
September 17, 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#e88e9ac681869b988d8b9c818786a886899a89c68f879e"><span class="__cf_email__" data-cfemail="294f5b0740475a594c4a5d4046476947485b48074e465f">[email protected]</span></a>.
Issued on March 31, 2026.
Victor Wicklund,
Acting Director, Integrated Certificate Management Division, Aircraft
Certification Service.
[FR Doc. 2026-06471 Filed 4-1-26; 8:45 am]
BILLING CODE 4910-13-P
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