Airworthiness Directive for Airbus A350-941 Fastener Retorque Process

Content

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for certain Airbus SAS Model A350-941 airplanes. This proposed
AD was prompted by a manufacturing investigation that found improper application of the fastener retorque process at the center
wing box (CWB) and belly fairing (BF) junctions could lead to insufficient clamping. This proposed AD would require replacing
each affected part and applying additional head nut cap protection. 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-2026-3475; 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, the mandatory continuing airworthiness information (MCAI), any comments
received, and other information. The street address for Docket Operations is listed above.

Material Incorporated by Reference:

• For European Union Aviation Safety Agency (EASA) material identified in this proposed AD, contact EASA, Konrad-Adenauer-Ufer
3, 50668 Cologne, Germany; telephone +49 221 8999 000; email ADs@easa.europa.eu. You may find this material on the EASA website at ad.easa.europa.eu. It is also available at regulations.gov under Docket No. FAA-2026-3475.

• 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.

FOR FURTHER INFORMATION CONTACT:

Anthony DeCaro, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: (562) 627-5374; email: anthony.d.decaro@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-2026-3475; Project Identifier MCAI-2025-01561-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
Anthony DeCaro, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: (562) 627-5374; email: anthony.d.decaro@faa.gov.

Any commentary that the FAA receives which is not specifically designated as CBI will be placed in the public docket for this
rulemaking.

Background

EASA, which is the Technical Agent for the Member States of the European Union, has issued EASA AD 2025-0209, dated September
24, 2025 (EASA AD 2025-0209) (also referred to as the MCAI), to correct an unsafe condition for certain Airbus SAS Model A350-941
airplanes. The MCAI states that during manufacturing investigation of an early production A350-941 airplane, it was found
that improper application of the fastener retorque process at the CWB and BF junctions could lead to insufficient clamping.
Fasteners with part number EN6115 code B were particularly susceptible to rotation, and if not torqued correctly, could potentially
compromise structural integrity and compliance with the electromagnetic hazard requirements of the airplane. This condition,
if not corrected, could, in the case of a fuel leak, create a source of ignition, possibly resulting in an uncontrolled fire.

The FAA is proposing this AD to address the unsafe condition of these products.

You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2026-3475.

Material Incorporated by Reference Under 1 CFR Part 51

EASA AD 2025-0209 specifies procedures for replacing affected fasteners installed on the left-hand (LH) and right-hand (RH)
sides of the CWB and BF junctions and applying additional head nut cap protection. 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.

FAA's Determination

These products have been approved by the civil aviation authority of another country and are approved for operation in the
United States. Pursuant to the FAA's bilateral agreement with this State of Design Authority, that authority

  has notified the FAA of the unsafe condition described in the MCAI referenced above. The FAA is issuing this NPRM after determining
  that the unsafe condition described previously is likely to exist or develop in other products of the same type design.

Proposed AD Requirements in This NPRM

This proposed AD would require accomplishing the actions specified in EASA AD 2025-0209 described previously, except for any
differences identified as exceptions in the regulatory text of this proposed AD.

Explanation of Required Compliance Information

In the FAA's ongoing efforts to improve the efficiency of the AD process, the FAA developed a process to use some civil aviation
authority (CAA) ADs as the primary source of information for compliance with requirements for corresponding FAA ADs. The FAA
has been coordinating this process with manufacturers and CAAs. As a result, the FAA proposes to incorporate EASA AD 2025-0209
by reference in the FAA final rule. This proposed AD would, therefore, require compliance with EASA AD 2025-0209 in its entirety
through that incorporation, except for any differences identified as exceptions in the regulatory text of this proposed AD.
Using common terms that are the same as the heading of a particular section in EASA AD 2025-0209 does not mean that operators
need comply only with that section. For example, where the AD requirement refers to “all required actions and compliance times,”
compliance with this AD requirement is not limited to the section titled “Required Action(s) and Compliance Time(s)” in EASA
AD 2025-0209. Material required by EASA AD 2025-0209 for compliance will be available at regulations.gov under Docket No. FAA-2026-3475 after the FAA final rule is published.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would affect 2 airplanes of U.S. registry. The FAA estimates the following
costs to comply with this proposed AD:

Labor cost	Parts cost	Cost per product	Cost on U.S. operators
Up to 68 work hours × $85 per hour = $5,780	Up to $940	Up to $6,720	Up to $13,440.

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:

Airbus SAS:
Docket No. FAA-2026-3475; Project Identifier MCAI-2025-01561-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 Airbus SAS Model A350-941 airplanes, certificated in any category, as identified in European Union Aviation
Safety Agency (EASA) AD 2025-0209, dated September 24, 2025 (EASA AD 2025-0209).

(d) Subject

Air Transport Association (ATA) of America Code 57, Wings.

(e) Unsafe Condition

This AD was prompted by a manufacturing investigation that found improper application of the fastener retorque process at
the center wing box (CWB) and belly fairing (BF) junctions could lead to insufficient clamping. The FAA is issuing this AD
to address improperly torqued fasteners that could lead to insufficient clamping and potentially compromise the airplane's
structural integrity and compliance with electromagnetic hazard requirements. The unsafe condition, if not addressed, could,
in case of a fuel leak, create a source of ignition and possibly result in an uncontrolled fire.

(f) Compliance

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

(g) Requirements

Except as specified in paragraph (h) of this AD: Comply with all required actions and compliance times specified in, and in
accordance with, EASA AD 2025-0209.

(h) Exceptions to EASA AD 2025-0209

(1) Where EASA AD 2025-0209 refers to its effective date, this AD requires using the effective date of this AD.

(2) Where the definition of “Affected parts” in EASA AD 2025-0209 specifies “as

  specified in the SB”, this AD requires replacing that text with “Airbus Service Bulletin A350-57-P093, dated June 17, 2025”.

(3) This AD does not adopt the “Remarks” section of EASA AD 2025-0209.

(i) Additional AD Provisions

The following provisions also apply to this AD:

(1) Alternative Methods of Compliance (AMOCs): 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 (i) of this AD and email 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) Contacting the Manufacturer: For any requirement in this AD to obtain instructions from a manufacturer, the instructions must be accomplished using a method
approved by the Manager, AIR-520, Continued Operational Safety Branch, FAA; or EASA; or Airbus SAS's EASA Design Organization
Approval (DOA). If approved by the DOA, the approval must include the DOA-authorized signature.

(3) Required for Compliance (RC): Except as required by paragraph (i)(2) of this AD, if any material contains procedures or tests that are identified as RC,
those procedures and tests must be done to comply with this AD; any procedures or tests that are not identified as RC are
recommended. Those procedures and tests that are not identified as RC may be deviated from using accepted methods in accordance
with the operator's maintenance or inspection program without obtaining approval of an AMOC, provided the procedures and tests
identified as RC can be done and the airplane can be put back in an airworthy condition. Any substitutions or changes to procedures
or tests identified as RC require approval of an AMOC.

(i) Additional Information

For more information about this AD, contact Anthony DeCaro, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines,
WA 98198; phone: (562) 627-5374; email: anthony.d.decaro@faa.gov.

(j) 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 this AD specifies otherwise.

(i) European Union Aviation Safety Agency (EASA) AD 2025-0209, dated September 24, 2025.

(ii) [Reserved]

(3) For EASA material identified in this AD, contact EASA, Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; telephone +49 221
8999 000; email ADs@easa.europa.eu. You may find this material on the EASA website at ad.easa.europa.eu.

(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 April 1, 2026. Victor Wicklund, Acting Director, Integrated Certificate Management Division, Aircraft Certification Service. [FR Doc. 2026-06563 Filed 4-2-26; 8:45 am] BILLING CODE 4910-13-P

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