Airworthiness Directives; Airbus Helicopters

DEPARTMENT OF TRANSPORTATION <SUBAGY>Federal Aviation Administration</SUBAGY> <CFR>14 CFR Part 39</CFR> <DEPDOC>[Docket No. FAA-2025-1735; Project Identifier MCAI-2024-00408-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 supersede Airworthiness Directive (AD) 2021-20-16, which applies to all Airbus Helicopters Model AS355E, AS 355-F, AS 355-F1, AS355F2, AS355N, and AS355NP helicopters and certain Model AS 350B3 helicopters. AD 2021-20-16 requires repetitive cleaning and visual and detailed inspections of the right-hand side of the vertical fin spar and vertical fin upper attachments for discrepancies (cracking) with corrective action, if necessary. Since the FAA issued AD 2021-20-16, Airbus Helicopters developed a modification of the upper fin assembly. This proposed AD would require the same actions as AD 2021-20-16 and would also require replacement of the upper fin assembly with a modified upper fin assembly, which would constitute terminating action for the repetitive inspections. 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 October 6, 2025. </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-2025-1735; 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 European Union Aviation Agency (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. It is also available at <E T="03">regulations.gov</E> under Docket No. FAA-2025-1735. <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Steven Warwick, Aviation Safety Engineer, FAA, 1600 Stewart Ave., Suite 410, Westbury, NY 11590; phone: (817) 222-5225; email: <E T="03">steven.r.warwick@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 to an address listed under the <E T="02">ADDRESSES</E> section. Include “Docket No. FAA-2025-1735; Project Identifier MCAI-2024-00408-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 the 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. <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 Steven Warwick, Aviation Safety Engineer, FAA, 1600 Stewart Ave., 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> The FAA issued AD 2021-20-16, Amendment 39-21754 (86 FR 57550, dated October 18, 2021) (AD 2021-20-16), for Airbus Helicopters Model AS355E, AS 355-F, AS 355-F1, AS355F2, AS355N, and AS355NP helicopters, all serial numbers, and Model AS 350B3 helicopters, all serial numbers except those that have Airbus Helicopters Modification 073148 in production. AD 2021-20-16 was prompted by MCAI originated by EASA, which is the Technical Agent for the Member States of the European Union. EASA issued EASA AD 2021-0099, dated April 9, 2021 (EASA AD 2021-0099), to correct an unsafe condition identified as cracking in the spar of the upper part of the vertical fin and fractures in the front attachment screws. AD 2021-20-16 requires repetitive cleaning and detailed inspections for cracking of the vertical fin spar and vertical fin upper attachments, and corrective action if necessary. The FAA issued this AD to address cracking in the spar of the upper part of the vertical fin and fractures in the front attachment screws. This condition could lead to in-flight separation of the upper part of the vertical fin, resulting in loss of control of the helicopter. <HD SOURCE="HD1">Actions Since AD 2021-20-16 Was Issued</HD> Since the FAA issued AD 2021-20-16, EASA superseded EASA AD 2021-0099 through a series of ADs, the most recent being EASA AD 2024-0139, dated July 12, 2024 (EASA AD 2024-0139) (also referred to as “the MCAI”). EASA AD 2024-0139 states that after a further occurrence of a crack on a Model AS355NP helicopter, EASA concluded there was a need to temporarily reduce the never-exceed-speed (V <E T="52">NE</E> ) for all AS355 helicopters. In addition, Airbus Helicopters developed a reinforced upper fin assembly and published service information that provides instructions for this modification. EASA AD 2024-0139 retains the repetitive inspections and V <E T="52">NE</E> limitations in its previous ADs and also requires modification of the helicopter with the reinforced upper fin assembly, which is terminating action for inspections and limitations. You may examine the MCAI in the AD docket at <E T="03">regulations.gov</E> under Docket No. FAA-2025-1735. <HD SOURCE="HD1">Material Incorporated by Reference Under 1 CFR Part 51</HD> The FAA reviewed EASA AD 2024-0139, which specifies procedures for amending the rotorcraft flight manual (RFM) and installing a placard to add a speed limitation. EASA AD 2024-0139 allows exceeding the speed limitation on certain maintenance flights and specifies accomplishing an inspection after each flight where the speed is exceeded. EASA AD 2024-0139 also requires repetitively inspecting the right-hand external side around the two top screws of certain upper fin spars for a crack. EASA AD 2024-0139 specifies that installing an upper fin assembly P/N 355A14-0522-1751 constitutes terminating action for the repetitive inspection requirements and the speed limitations. Lastly, EASA AD 2024-0139 prohibits installing affected 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 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. <HD SOURCE="HD1">Proposed AD Requirements in This NPRM</HD> This proposed AD would require accomplishing the actions specified in EASA AD 2024-0139, 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 Proposed AD and the MCAI” for a general discussion of these differences. <HD SOURCE="HD1">Explanation of Required Compliance Information</HD> In the FAA's ongoing efforts to improve the efficiency of the AD proce ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 24k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━