Airworthiness Directives; Airbus Helicopters

DEPARTMENT OF TRANSPORTATION <SUBAGY>Federal Aviation Administration</SUBAGY> <CFR>14 CFR Part 39</CFR> <DEPDOC>[Docket No. FAA-2025-5039; Project Identifier MCAI-2024-00426-R]</DEPDOC> <RIN>RIN 2120-AA64</RIN> <SUBJECT>Airworthiness Directives; Airbus Helicopters</SUBJECT> <HD SOURCE="HED">AGENCY:</HD> Federal Aviation Administration (FAA), DOT. <HD SOURCE="HED">ACTION:</HD> Notice of proposed rulemaking (NPRM). <SUM> <HD SOURCE="HED">SUMMARY:</HD> The FAA proposes to adopt a new airworthiness directive (AD) for all Airbus Helicopters Model AS355E, AS 355-F, AS 355-F1, AS355F2, AS355N, and AS355NP helicopters. This proposed AD was prompted by a report of a structural crack in the vertical attachment spar of the tail fin. This proposed AD would require repetitive inspections of certain vertical upper fin spars and, depending on the results, corrective action. This proposed AD would also prohibit installing certain upper fin assemblies. The FAA is proposing this AD to address the unsafe condition on these products. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> The FAA must receive comments on this NPRM by February 2, 2026. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods: • <E T="03">Federal eRulemaking Portal:</E> Go to <E T="03">regulations.gov</E> . Follow the instructions for submitting comments. • <E T="03">Fax:</E> (202) 493-2251. • <E T="03">Mail:</E> U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590. • <E T="03">Hand Delivery:</E> Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. <E T="03">AD Docket:</E> You may examine the AD docket at <E T="03">regulations.gov</E> under Docket No. FAA-2025-5039; 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. <E T="03">Material Incorporated by Reference:</E> • For EASA material identified in this AD, contact EASA, Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; phone: +49 221 8999 000; email: <E T="03">ADs@easa.europa.eu;</E> website: <E T="03">easa.europa.eu.</E> You may find the EASA material on the EASA website at <E T="03">ad.easa.europa.eu.</E> • You may view this material at the FAA, Office of the Regional Counsel, Southwest Region, 10101 Hillwood Parkway, Room 6N-321, Fort Worth, TX 76177. For information on the availability of this material at the FAA, call (817) 222-5110. <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Yves Petiote, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (202) 975-4867; email: <E T="03">yves.petiote@faa.gov.</E> </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> <HD SOURCE="HD1">Comments Invited</HD> 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 <E T="02">ADDRESSES</E> section. Include “Docket No. FAA-2025-5039; Project Identifier MCAI-2024-00426-R” 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 <E T="03">regulations.gov,</E> including any personal information you provide. The agency will also post a report summarizing each substantive verbal contact received about this NPRM. <HD SOURCE="HD1">Confidential Business Information</HD> 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 Yves Petiote, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590. Any commentary that the FAA receives which is not specifically designated as CBI will be placed in the public docket for this rulemaking. <HD SOURCE="HD1">Background</HD> EASA, which is the Technical Agent for the Member States of the European Union, has issued a series of ADs, the most recent being EASA AD 2023-0154R1, dated July 19, 2024 (EASA AD 2023-0154R1) (also referred to as “the MCAI”), to correct an unsafe condition on all Airbus Helicopters Model AS 355 E, AS 355 F, AS 355 F1, AS355 F2, AS355 N, and AS 355 NP helicopters. The MCAI advises of a report of a structural crack (not a complete failure) in the vertical attachment spar of the tail fin. The MCAI states that the unsafe condition, if not addressed, may lead to in-flight separation of the upper part of the vertical fin, which could result in loss of control of the helicopter. The FAA is proposing this AD to address the unsafe condition on these products. EASA has issued related EASA AD 2024-0139, dated July 12, 2024 (EASA AD 2024-0139), for these same model helicopters as well as certain Model AS350B3 helicopters, to address cracking in a different area of the upper fin spar as well as the fin's front attachment screws. The FAA issued AD 2025-24-04, Amendment 39-23199 (90 FR 56679, December 8, 2025) (AD 2025-24-04), to address EASA AD 2024-0139. This proposed AD includes actions that would be contingent on some of the required actions in AD 2025-24-04. You may examine the MCAI in the AD docket at <E T="03">regulations.gov</E> under Docket No. FAA-2025-5039. <HD SOURCE="HD1">Material Incorporated by Reference Under 1 CFR Part 51</HD> FAA reviewed EASA AD 2023-0154R1, which specifies procedures for removing the tail gear box (TGB) fairing and the rear fairing from the tail boom, cleaning, and inspecting the right-hand external side around the two top screws of certain upper fin spars for a crack. EASA AD 2023-0154R1 also specifies procedures for conducting repetitive borescope inspections of that upper fin spar area for a crack or repeating the initial inspection as an alternative. Additionally, EASA AD 2023-0154R1 specifies accomplishing the inspections prior to and after maintenance flights that exceed the reduced V <E T="52">NE</E> (Velocity Never Exceed) required by EASA AD 2024-0139 and after each other flight that exceeds the reduced V <E T="52">NE</E> required by EASA AD 2024-0139. Depending on the results of an inspection, EASA AD 2023-0154R1 specifies procedures for marking the two top right-hand screw ends or replacing the upper fin. EASA AD 2023-0154R1 further specifies that installing an upper fin assembly part number (P/N) 355A14-0522-1751 constitutes terminating action for its repetitive inspection requirements and prohibits installing certain upper fin assemblies on any helicopter. 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 <E T="02">ADDRESSES</E> section. <HD SOURCE="HD1">FAA's Determination</HD> These products have been approved by the 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, it has notified the FAA of the unsafe condition described in the MCAI referenced above. The FAA is proposing this AD after evaluating all known relevant information and determining that the unsafe condition described previously is likely to exist or develop on other products of the same type design. <HD SOURCE="HD1">Proposed AD Requirements in This NPRM</HD> This proposed AD would require accomplishing the actions specified in EASA AD 2023-0154R1, described previously, as incorporated by reference, except for any differences identified as exceptions in the regulatory text of this proposed AD. See “Differences Between this AD and the MCAI” for a discussion of these differences. <HD SOURCE="HD1">Differences Between This Proposed AD and the MCAI</HD> Where the MCAI defines an affected part as those listed in any revision of the manufacturer's service information, this proposed AD would define an affected part as those listed in specific versions of the manufacturer's service information and would include upper fin assemblies for which the P/N cannot be determined. <HD SOURCE="HD1">Explanation of Required Compliance Information</HD> 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 2023-0154R1 by reference in the FAA final rule. 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