AD 2025-20-05

This AD is effective December 30, 2025.

The Director of the Federal Register approved the incorporation by reference of certain publications listed in this AD as of December 30, 2025.

AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA-2025-0340; 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 final rule, the mandatory continuing airworthiness information (MCAI), any comments received, and other information. The address for Docket Operations is U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.

Material Incorporated by Reference:

• For European Union Aviation Safety Agency (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.

• 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.

• 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-2025-0340.

Promita Dey, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; telephone 316-946-4106; email promita.dey@faa.gov.

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.

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.

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.

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.

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.

The FAA estimates that this AD affects 36 airplanes of U.S. registry. The FAA estimates the following costs to comply with this AD:

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:

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.

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.

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.

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:

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

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: