Background The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2023-14-09, Amendment 39-22509 (88 FR 51227, August 3, 2023) (AD 2023-14-09). AD 2023-14-09 applied to certain Airbus SAS Model A350-941 and -1041 airplanes. AD 2023-14-09 required an inspection for missing or incorrectly applied sealant in the wing tanks, applicable corrective actions, and a modification to restore the two independent layers of lightning strike protection. AD 2023-14-09 corresponds to EASA AD 2022-0250, dated December 14, 2022 (EASA AD 2022-0250). The FAA issued AD 2023-14-09 to address missing or incorrect application of the lightning strike edge glow sealant protection at specific locations on the wing tanks. This sealant provides the second layer or protection to prevent stringer edge glow in case of lightning strike. The NPRM was published in the Federal Register on March 11, 2025 (90 FR 11683). The NPRM was prompted by AD 2024-0155, dated August 13, 2024, issued by EASA, which is the Technical Agent for the Member States of the European Union (EASA AD 2024-0155) (also referred to as the MCAI). The MCAI states that since EASA AD 2022-0250 was issued, Airbus published inspection instructions for a new one-time DET for missing or incorrect application of the lightning strike edge glow sealant protection of the affected upper and lower front and rear spar corner fittings between Rib 1 and Rib 2 for certain airplanes ( i.e., an additional affected area not identified in EASA AD 2022-0250), and depending on findings, accomplishment of applicable corrective actions. Missing or incorrectly applied sealant, combined with a pre-existing undetected incorrect installation of an adjacent fastener, if not detected and corrected, could create an ignition source for the fuel vapor inside the tanks, which, in case of a lightning strike of high intensity in the immediate area, could possibly result in ignition of the fuel-air mixture in the affected fuel tank and consequent loss of the airplane. In the NPRM, the FAA proposed to continue to require the actions in AD 2023-14-09 and proposed to require a one-time DET for missing or incorrectly applied sealant of the front and rear spars for certain airplanes and applicable corrective actions, as specified in EASA AD 2024-0155. The FAA is issuing this AD to address the unsafe condition on these products. You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2025-0340. Discussion of Final Airworthiness Directive Comments The FAA received comments from the Air Line Pilots Association, International, (ALPA) and ProTech Aero Services Limited (ProTech) who supported the NPRM without change. The FAA received an additional comment from Delta Air Lines (Delta). The following presents the comment received on the NPRM and the FAA's response to the comment. Request for Continue Use of Previously Approved Alternative Methods of Compliance (AMOCs) Delta requested the FAA grant approval to continue using the previously approved AMOC AIR-731-23-00454a, dated November 1, 2023. Delta stated that the FAA had approved the stated AMOC, allowing the omission of pipe tests if the pipes were not removed during access, for AD 2023-14-09. Delta noted this proposed AD retains the requirements of AD 2023-14-09. The FAA disagrees with the commenter's request. This AD adds additional affected areas for inspection; therefore a new AMOC is required or a revision to AMOC AIR-731-23-00454a, dated November 1, 2023, is required that includes those additional inspection areas. The FAA has not changed the AD in this regard. Conclusion 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 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, 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 EASA AD 2024-0155, which specifies procedures for an inspection for discrepancies (missing or incorrect application of the lightning strike edge glow sealant protection) at certain locations in the wing tanks, and corrective actions. EASA AD 2024-0155 also specifies procedures for sealant application to the lower and/or upper rib feet in the wings and an inspection for missing or incorrectly applied sealant on the upper and lower, front and rear spar corner fittings between Rib 1 and Rib 2 for certain airplanes, and corrective actions. Corrective actions include applying sealant in areas where sealant was found to be missing or incorrectly applied. The FAA also reviewed Airbus Service Bulletin A350-57-P067, dated September 17, 2020; Airbus Service Bulletin A350-57-P070, Revision 01, dated March 14, 2022; Airbus Service Bulletin A350-57-P072, dated June 24, 2022; Airbus Service Bulletin A350-57-P073, dated June 24, 2022; Airbus Service Bulletin A350-57-P074, dated June 24, 2022; and Airbus Service Bulletin A350-57-P091, dated May 30, 2024; which identify affected airplanes. These documents are distinct since they apply to different airplane configurations. 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 36 airplanes of U.S. registry. The FAA estimates the following costs to comply with this AD: Estimated Costs for Required Actions Action Labor cost Parts cost Cost per product Cost on U.S. operators Retained actions from AD 2023-14-09 Up to 225 work-hours × $85 per hour = $19,125 Up to $500 Up to $19,625 Up to $706,500. New actions Up to 39 work-hours × $85 per hour = $3,315 $0 Up to $3,315 Up to $119,340. The FAA estimates the following costs to do any necessary corrective action that would be required based on the results of any required actions. The FAA has no way of determining the number of aircraft that might need the corrective actions: Estimated Costs of Corrective Actions Labor cost Parts cost Cost per product 10 work-hours × $85 per hour = $850 Minimal $850 According to the manufacturer, some or all of the costs of this AD may be covered under warranty, thereby reducing the cost impact on affected operators. The FAA does not control warranty coverage for affected operators. As a result, the FAA has included all known costs in the cost estimate. 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 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: a. Removing Airworthiness Directive (AD) 2023-14-09, Amendment 39-22509 (88 FR 51227, August 3, 2023); and b. Adding the following new AD: 2025-20-05 Airbus SAS: Amendment 39-23158; Docket No. FAA-2025-0340; Project Identifier MCAI-2024-00462-T. (a) Effective Date This airworthiness directive (AD) is effective December 30, 2025. (b) Affected ADs This AD replaces AD 2023-14-09, Amendment 39-22509 (88 FR 51227, August 3, 2023) (AD 2023-14-09). (c) Applicability This AD applies to Airbus SAS Model A350-941 and -1041 airplanes, certificated in any category, with manufacturer serial numbers (MSN) identified in any service bulletin listed in paragraphs (c)(1) through (6) of this AD. (1) Airbus Service Bulletin A350-57-P067, dated September 17, 2020. (2) Airbus Service Bulletin A350-57-P070, Revision 01, dated March 14, 2022. (3) Airbus Service Bulletin A350-57-P072, dated June 24, 2022. (4) Airbus Service Bulletin A350-57-P073, dated June 24, 2022. (5) Airbus Service Bulletin A350-57-P074, dated June 24, 2022. (6) Airbus Service Bulletin A350-57-P091, dated May 30, 2024. (d) Subject Air Transport Association (ATA) of America Code 57, Wings. (e) Unsafe Condition This AD was prompted by reports of missing or incorrect application of the lightning strike edge glow sealant protection at specific locations on the wing tanks. The FAA is issuing this AD to address missing or incorrectly applied sealant. The unsafe condition, if not addressed, could result in ignition of the fuel-air mixture in the affected fuel tank and consequent loss of the airplane. (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, European Union Aviation Safety Agency (EASA) AD 2024-0155, dated August 13, 2024 (EASA AD 2024-0155). (h) Exceptions to EASA AD 2024-0155 (1) Where EASA AD 2024-0155 refers to its effective date, this AD requires using the effective date of this AD. (2) Where paragraph (1) of EASA AD 2024-0155 gives a compliance time of "the next scheduled maintenance tank entry, or before exceeding 78 months since aeroplane date of manufacture, whichever occurs first after 27 October 2020 [the effective date of EASA AD 2020-0220]," for this AD, the compliance time is the later of the times specified in paragraphs (h)(2)(i) and (ii) of this AD. (i) The next scheduled maintenance tank entry, or before exceeding 78 months since airplane date of manufacture, whichever occurs first after September 30, 2021 (the effective date of AD 2021-16-03, Amendment 39-21665 (86 FR 47555, August 26, 2021) (AD 2021-16-03)). (ii) Within 12 months after September 30, 2021 (the effective date of AD 2021-16-03). (3) Where paragraph (4) of EASA AD 2024-0155 gives a compliance time of "the next scheduled maintenance tank entry, or before exceeding 78 months since aeroplane date of manufacture, whichever occurs first after 04 February 2022 [the effective date of EASA AD 2022-0011]," for this AD, the compliance time is the later of the times specified in paragraphs (h)(3)(i) and (ii) of this AD. (i) The next scheduled maintenance tank entry, or before exceeding 78 months since airplane date of manufacture, whichever occurs first after November 29, 2022 (the effective date of AD 2022-17-09, Amendment 39-22147 (87 FR 64375, October 25, 2022) (AD 2022-17-09)). (ii) Within 12 months after November 29, 2022 (the effective date of AD 2022-17-09). (4) Where paragraph (5) of EASA AD 2024-0155 gives a compliance time of "the next scheduled maintenance tank entry, or before exceeding 78 months since aeroplane date of manufacture, whichever occurs first after 28 December 2022 [the effective date of EASA AD 2022-0250]," for this AD, the compliance time is the later of the times specified in paragraphs (h)(4)(i) and (ii) of this AD. (i) The next scheduled maintenance tank entry, or before exceeding 78 months since airplane date of manufacture, whichever occurs first after September 7, 2023 (the effective date of AD 2023-14-09). (ii) Within 12 months after September 7, 2023 (the effective date of AD 2023-14-09). (5) Where paragraph (2) of EASA AD 2024-0155 gives a compliance time of "the next scheduled maintenance tank entry, or before exceeding 78 months after the effective date of this [EASA] AD," for this AD, the compliance time is the later of the times specified in paragraphs (h)(5)(i) and (ii) of this AD. (i) The next scheduled maintenance tank entry, or before exceeding 78 months after the effective date of this AD, whichever occurs first. (ii) Within 2 months after the effective date of this AD. (6) Where paragraph (3) of EASA AD 2024-0155 refers to "discrepancies," for this AD, discrepancies include missing or incorrectly applied sealant. (7) This AD does not adopt the "Remarks" section of EASA AD 2024-0155. (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 (j) of this AD and email to: AMOC@faa.gov. (i) 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. (j) Additional Information For more information about this AD, contact Promita Dey, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; telephone 316-946-4106; email promita.dey@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 this AD specifies otherwise. (i) Airbus Service Bulletin A350-57-P067, dated September 17, 2020. (ii) Airbus Service Bulletin A350-57-P070, Revision 01, dated March 14, 2022. (iii) Airbus Service Bulletin A350-57-P072, dated June 24, 2022. (iv) Airbus Service Bulletin A350-57-P073, dated June 24, 2022. (v) Airbus Service Bulletin A350-57-P074, dated June 24, 2022. (vi) Airbus Service Bulletin A350-57-P091, dated May 30, 2024. (vii) European Union Aviation Safety Agency (EASA) AD 2024-0155, dated August 13, 2024. (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; website easa.europa.eu. You may find this material on the EASA website at ad.easa.europa.eu. (4) For Airbus material identified in this AD, contact Airbus SAS, Airworthiness Office-EAL, Rond-Point Emile Dewoitine No: 2, 31700 Blagnac Cedex, France; telephone +33 5 61 93 36 96; fax +33 5 61 93 45 80; email continued-airworthiness.a350@airbus.com; website airbus.com. (5) 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. (6) 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 September 24, 2025. Peter A. White, Deputy Director, Integrated Certificate Management Division, Aircraft Certification Service.