Airworthiness Directive Boeing 757-300 Upper Frame Crack Inspection

Content

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for all The Boeing Company Model 757-300 series airplanes. This
proposed AD was prompted by a crack growth analysis that indicated that existing maintenance planning data (MPD) and supplemental
structural inspection program (SSIP) tasks do not provide adequate inspection opportunities to detect cracks in the upper
frames around the uppermost fastener common to the fail-safe chord at the fuselage frame splices. This proposed AD would require
an inspection or maintenance record check for existing repairs, repetitive inspections of the upper frames around the uppermost
fastener common to the fail-safe chord at the fuselage frame splices for any cracks, 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:

• Federal eRulemaking Portal: Go to regulations.gov. Follow the instructions for submitting comments.

• Fax: 202-493-2251.

• 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.

• 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 regulations.gov under Docket No. FAA-2026-2730; 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:

• 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 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-2026-2730.

FOR FURTHER INFORMATION CONTACT:

Wayne Ha, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 562-627-5238; email: wayne.ha@faa.gov.

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-2026-2730; Project Identifier AD-2025-01579-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 regulations.gov, 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: wayne.ha@faa.gov. Any commentary that the FAA receives that is not specifically designated as CBI will be placed in the public docket for this
rulemaking.

Background

The FAA has received a report that crack growth analysis indicated that existing MPD and SSIP tasks do not provide adequate
inspection opportunities to detect cracks in the upper frames around the uppermost fastener common to the fail-safe chord
at the fuselage frame splices between stringers S-13 to S-14, from station (STA) 1380 to STA 1620. Any undetected crack in
the upper frames around the uppermost fastener common to the S-13 to S-14 frame splices could

  lead to multiple upper frame failures. This condition, if not addressed, could result in the inability of a principal structural
  element to sustain limit loads and the loss of continued safe flight and landing.

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 757-53A0122 RB, dated September 26, 2025. This material specifies procedures
for performing a general visual inspection or a maintenance records check of the forward and aft sides of the upper frames
at the frame splices between S-13 and S-14 on the left and right sides, from STA 1380 to STA 1620, for any repair and applicable
on-condition actions. On-condition actions include contacting Boeing for alternative inspection and corrective action instructions
and doing the alternative inspection and applicable corrective actions in the repaired areas.

This material also specifies procedures for repetitive detailed inspections of the upper frames around the uppermost fastener
common to the fail-safe chord at the frame splices between S-13 and S-14 on the left and right sides, from STA 1380 to STA
1620, 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 regulations.gov under Docket No. FAA-2026-2730.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would affect 37 airplanes of U.S. registry. The FAA estimates the
following costs to comply with this proposed AD:

Action	Labor cost	Parts cost	Cost per product	Cost on U.S. operators
General visual inspection or maintenance records check	Up to 70 work-hours × $85 per hour = $5,950	$0	Up to $5,950	Up to $220,150.
Detailed inspection	4 work-hours × $85 per hour = $340 per inspection cycle	0	$340 per inspection cycle	$12,580 per inspection cycle.

The FAA has received no definitive data on which to base the cost estimates for the alternative inspections and on-condition
actions 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

1. The authority citation for part 39 continues to read as follows:

Authority:

49 U.S.C. 106(g), 40113, 44701.

§ 39.13 [Amended] 2. The FAA amends § 39.13 by adding the following new airworthiness directive:

The Boeing Company:
Docket No. FAA-2026-2730; Project Identifier AD-2025-01579-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 all The Boeing Company Model 757-300 series airplanes, certificated in any category.

(d) Subject

Air Transport Association (ATA) of America Code 53, Fuselage.

(e) Unsafe Condition

This AD was prompted by a crack growth analysis that indicated that the existing maintenance planning data and supplemental
structural inspection program tasks do not provide adequate inspection opportunities to detect cracks in the upper frames
around the uppermost fastener common to the fail-safe chord at certain fuselage frame splices. The FAA is issuing this AD
to address cracking in the upper frames around the uppermost fastener common to the fail-safe chord at certain fuselage frame
splices, which could lead to

  multiple upper frame failures. The unsafe condition, if not addressed, could result in the inability of a principal structural
  element to sustain limit loads and the loss of continued safe flight and landing.

(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 757-53A0122 RB, dated September 26, 2025, do all applicable actions identified in, and in accordance
with, the Accomplishment Instructions of Boeing Alert Requirements Bulletin 757-53A0122 RB, dated September 26, 2025.

Note 1 to paragraph (g):
Guidance for accomplishing the actions required by this AD can be found in Boeing Alert Service Bulletin 757-53A0122, dated
September 26, 2025, which is referred to in Boeing Alert Requirements Bulletin 757-53A0122 RB, dated September 26, 2025.

(h) Exceptions to Requirements Bulletin Specifications

(1) Where the Compliance Time column of the tables in the “Compliance” paragraph of Boeing Alert Requirements Bulletin 757-53A0122
RB, dated September 26, 2025, refers to the original issue date of Requirements Bulletin 757-53A0122 RB, this AD requires
using the effective date of this AD.

(2) Where Boeing Alert Requirements Bulletin 757-53A0122 RB, dated September 26, 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: AMOC@faa.gov. 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

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: wayne.ha@faa.gov.

(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 757-53A0122 RB, dated September 26, 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 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 fr.inspection@nara.gov.

Issued on March 27, 2026. Lona C. Saccomando, Acting Deputy Director, Integrated Certificate Management Division, Aircraft Certification Service. [FR Doc. 2026-06385 Filed 4-1-26; 8:45 am] BILLING CODE 4910-13-P

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