2025-25-01: Main Rotor Drive System

1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. 106(g), 40113, 44701. 2. The FAA amends § 39.13 by adding the following new airworthiness directive: 2025-25-01 Bell Textron Canada Limited Helicopters: Amendment 39-23209; Docket No. FAA-2025-1727; Project Identifier MCAI-2024-00750-R. (a) Effective Date This airworthiness directive (AD) is effective January 16, 2026. (b) Affected ADs None. (c) Applicability This AD applies to Bell Textron Canada Limited Model 427 helicopters, serial numbers 56001 through 56084 inclusive, 58001, and 58002, certificated in any category. (d) Subject Joint Aircraft System Component (JASC) Code: 6300, Main Rotor Drive System. (e) Unsafe Condition This AD was prompted by a report of a cracked transmission oil check valve (check valve). The FAA is issuing this AD to detect and address cracked or leaking check valves. The unsafe condition, if not addressed, could result in the degradation or loss of lubrication to the transmission, failure of the transmission, and consequent loss of control of the helicopter. (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, Transport Canada AD CF-2024-42, dated December 13, 2024 (Transport Canada AD CF-2024-42). (h) Exceptions to Transport Canada AD CF-2024-42 (1) Where Transport Canada AD CF-2024-42 refers to its effective date, this AD requires using the effective date of this AD. (2) Where Transport Canada AD CF-2024-42 refers to air time, this AD requires using hours time-in-service. (3) Where Parts I and II of Transport Canada AD CF-2024-42 state "new," this AD requires replacing each instance of that text with "new (zero hours time-in-service)". (i) Alternative Methods of Compliance (AMOCs) (1) The Manager, International Validation 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 local Flight Standards District Office, as appropriate. If sending information directly to the manager of the International Validation Branch, send it to the attention of the person identified in paragraph (j) of this AD and email to: AMOC@faa.gov. (2) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/certificate holding district office. (j) Additional Information For more information about this AD, contact Michael Yeshiambel, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (316) 946-4133; email: michael.m.yeshiambel@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 the AD specifies otherwise. (i) Transport Canada AD CF-2024-42, dated December 13, 2024. (ii) [Reserved] (3) For Transport Canada material identified in this AD, contact Transport Canada, Transport Canada National Aircraft Certification, 159 Cleopatra Drive, Nepean, Ontario, K1A 0N5, Canada; phone: (888) 663-3639; email: TC.AirworthinessDirectives-Consignesdenavigabilite.TC@tc.gc.ca; website: tc.canada.ca/en/aviation. You may find the Transport Canada material on the Transport Canada website at tc.canada.ca/en/aviation. (4) 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. (5) 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 December 3, 2025. Steven W. Thompson, Acting Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service. [FR Doc. 2025-22623 Filed 12-11-25; 8:45 am]BILLING CODE 4910-13-P