Airworthiness Directives; Airbus Helicopters

DEPARTMENT OF TRANSPORTATION <SUBAGY>Federal Aviation Administration</SUBAGY> <CFR>14 CFR Part 39</CFR> <DEPDOC>[Docket No. FAA-2025-5032; Project Identifier AD-2025-01042-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) 2025-06-04, which applies to all Airbus Helicopters Model AS350B, AS350B1, AS350B2, AS350B3, AS350BA, AS350D, AS355E, AS355F, AS355F1, AS355F2, AS355N, AS355NP, EC130B4, and EC130T2 helicopters. AD 2025-06-04 requires repetitively inspecting the main gearbox (MGB) bevel wheel and the MGB magnetic plug for particles and performing corrective actions if applicable and prohibits installing an affected MGB unless certain requirements are met. Since the FAA issued AD 2025-06-04, the FAA determined that AD 2025-06-04 contains errors in the interval compliance times. This proposed AD would continue to require the actions of AD 2025-06-04 and revise the interval compliance times. 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 proposed AD by January 9, 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-2025-5032; 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 Safety Agency (EASA) material identified in this proposed 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 this 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> Dan McCully, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (404) 474-5548; email: <E T="03">william.mccully@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-2025-5032; Project Identifier AD-2025-01042-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 revise 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 Dan McCully, 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> The FAA issued AD 2025-06-04, Amendment 39-22992 (90 FR 14723, April 4, 2025) (AD 2025-06-04), for all Airbus Helicopters Model AS350B, AS350B1, AS350B2, AS350B3, AS350BA, AS350D, AS355E, AS355F, AS355F1, AS355F2, AS355N, AS355NP, EC130B4, and EC130T2 helicopters. AD 2025-06-04 was prompted by EASA AD 2023-0044, dated February 28, 2023 (EASA AD 2023-0044) (also referred to as the MCAI), issued by EASA, which is the Technical Agent for the Member States of the European Union. The MCAI states that after a fleet design review for detection of particles in the MGB, it was determined that additional maintenance actions are necessary to improve detection of particles in MGB that have certain part-numbered planet gear bearings installed. AD 2025-06-04 requires repetitively inspecting the MGB bevel wheel and the MGB magnetic plug for the presence of particles, close monitoring of the MGB magnetic plug if particles are detected, and replacing the epicyclic module if necessary. The AD also prohibits installing an affected MGB unless certain requirements are met. The agency issued AD 2025-06-04 to detect and correct the presence of particles in the MGB which, if not addressed, could result in reduced or loss of control of the helicopter. <HD SOURCE="HD1">Actions Since AD 2025-06-04 Was Issued</HD> Since the FAA issued AD 2025-06-04, the FAA determined that there are errors in the interval compliance times in Table 1 to paragraph (h)(6)(i) of AD 2025-06-04. Airbus Helicopters Model AS350B, AS350B1, AS350BA, AS350D, AS355E, AS355F, AS355F1, AS355F2, AS355N, and AS355NP helicopters should have an interval compliance time of 100 hours time-in-service (TIS) instead of 30 hours TIS. Also, Airbus Helicopters Model EC130B4 helicopters should have an interval compliance time of 100 hours TIS instead of 150 hours TIS. <HD SOURCE="HD1">FAA's Determination</HD> 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">Material Incorporated by Reference Under 1 CFR Part 51</HD> The FAA reviewed EASA AD 2023-0044, which specifies procedures for repetitive borescope visual inspections of the bevel wheel of the affected MGB for particles, collecting and analyzing any particles detected, and depending on the results, accomplishing further actions, accomplishing corrective action in accordance with the ASB, or contacting AH [Airbus Helicopters] for further corrective action. EASA AD 2023-0044 also specifies procedures for accomplishing a borescope visual inspection of the bevel wheel of the affected MGB for particles following the detection of any particles at the MGB magnetic plug during accomplishment of certain maintenance tasks and depending on the results, taking corrective action. EASA AD 2023-0044 also prohibits installing an affected MGB on any helicopter unless certain requirements are met. 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">Proposed AD Requirements in This NPRM</HD> This proposed AD would continue to require the actions of AD 2025-06-04, except that this proposed AD would revise the interval compliance times. The actions proposed in this AD are specified in EASA AD 2023-0044, 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 discussion of the general differences included in this proposed AD. <HD SOURCE="HD1">Differences Between This Proposed AD and the MCAI</HD> The MCAI applies to Model AS350BB helicopters, whereas this proposed AD would not because that model does not have an FAA type certificate. Where Note 1 in the material referenced in the MCAI specifies the option of 1 mechanical technician and 1 crew member, for this proposed AD, the pilot is only permitted to turn the tail rotor (b) because the other actions specified in the note must be accomplished by persons authorized under 14 CFR 43.3. Therefore, for the purposes of this proposed AD, the owner/operator (pilot) may turn the tail rotor (b) and must enter compliance with the applicable paragraph of this proposed AD in the he ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 28k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━