2025-01-03: Turbine Section

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: 2025-01-03 CFM International, S.A.: Amendment 39-22927; Docket No. FAA-2024-2325; Project Identifier AD-2024-00412-E. (a) Effective Date This airworthiness directive (AD) is effective March 11, 2025. (b) Affected ADs None. (c) Applicability This AD applies to the following CFM International, S.A. (CFM) engines: (1) Model LEAP-1A23, LEAP-1A24, LEAP-1A24E1, LEAP-1A26, LEAP-1A26CJ, LEAP-1A26E1, LEAP-1A29, LEAP-1A29CJ, LEAP-1A30, LEAP-1A32, LEAP-1A33, LEAP-1A33B2, and LEAP-1A35A engines. (2) Model LEAP-1C28, LEAP-1C30, and LEAP-1C30B1 engines. (d) Subject Joint Aircraft System Component (JASC) Code 7250, Turbine Section. (e) Unsafe Condition This AD was prompted by an investigation of an in-flight shut down event that revealed the aft arm of the high-pressure turbine (HPT) rotor interstage seal had failed. The FAA is issuing this AD to prevent failure of the HPT rotor interstage seal. The unsafe condition, if not addressed, could result in failure of one or more engines, loss of thrust control, and loss of the airplane. (f) Compliance Comply with this AD within the compliance times specified, unless already done. (g) Required Actions (1) For LEAP-1A engines having an HPT rotor interstage seal installed with a part number (P/N) and serial number (S/N) listed in Table 1 of CFM Service Bulletin (SB) LEAP-1A-72-00-0525-01A-930A-D, Issue 002-00, dated June 28, 2024 (CFM SB LEAP-1A-72-00-0525-01A-930A-D Issue 002-00), at the next engine shop visit or before exceeding the applicable cyclic threshold in table 1 to paragraph (g)(1) of this AD, whichever occurs first after the effective date of this AD, remove the affected HPT rotor interstage seal from service and replace with a part eligible for installation. Table 1 to Paragraph ( g )(1)-Removal Thresholds for Each Engine Model Engine model Removal cyclic threshold LEAP-1A23, LEAP-1A24, LEAP-1A24E1, LEAP-1A26, LEAP-1A26E1, LEAP-1A29, LEAP-1A30, LEAP-1A32, LEAP-1A33, LEAP-1A33B2, and LEAP-1A35A 11,100 cycles since new (CSN) accumulated on the affected part. LEAP-1A26CJ and LEAP-1A29CJ 9,700 CSN accumulated on the affected part. (2) For LEAP-1A engines having an HPT rotor interstage seal installed with a P/N and S/N listed in Table 2 of CFM SB LEAP-1A-72-00-0525-01A-930A-D Issue 002-00, at the next piece part exposure or before exceeding the applicable cyclic threshold in table 1 to paragraph (g)(1) of this AD, whichever occurs first after the effective date of this AD, remove the affected HPT rotor interstage seal from service and replace with a part eligible for installation. (h) Installation Prohibition (1) After the effective date of this AD, do not install an HPT rotor interstage seal having a P/N and S/N listed in Table 1 or Table 2 of CFM SB LEAP-1A-72-00-0525-01A-930A-D Issue 002-00, in any LEAP-1A engine. (2) After the effective date of this AD, do not install an HPT rotor interstage seal having a P/N and S/N listed in Table 1 of CFM SB LEAP-1C-72-00-0124-01A-930A-D, Issue 001-00, dated September 5, 2024, in any LEAP-1C engine. (i) Definitions For the purpose of this AD: (1) "LEAP-1A engines" are CFM Model LEAP-1A23, LEAP-1A24, LEAP-1A24E1, LEAP-1A26, LEAP-1A26CJ, LEAP-1A26E1, LEAP-1A29, LEAP-1A29CJ, LEAP-1A30, LEAP-1A32, LEAP-1A33, LEAP-1A33B2, LEAP-1A35A engines. (2) "LEAP-1C engines" are CFM Model LEAP-1C28, LEAP-1C30, and LEAP-1C30B1 engines. (3) A "part eligible for installation" is any HPT rotor interstage seal having a P/N and S/N that is not listed in Table 1 or Table 2 of CFM SB LEAP-1A-72-00-0525-01A-930A-D Issue 002-00. (4) An "engine shop visit" is the induction of an engine into the shop for maintenance involving the separation of major mating engine flanges, except for the separation of engine flanges solely for the purposes of transportation without subsequent engine maintenance. (5) A "piece-part exposure" is when the HPT rotor interstage seal is separated from the HPT rotor assembly. (j) Alternative Methods of Compliance (AMOCs) (1) The Manager, AIR-520 Continued Operational Safety 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 AIR-520 Continued Operational Safety Branch, send it to the attention of the person identified in paragraph (k) 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. (k) Additional Information For more information about this AD, contact Mehdi Lamnyi, Aviation Safety Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; phone: (781) 238-7743; email: mehdi.lamnyi@faa.gov. (l) Material Incorporated by Reference (1) The Director of the Federal Register approved the incorporation by reference (IBR) 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) CFM Service Bulletin LEAP-1A-72-00-0525-01A-930A-D, Issue 002-00, dated June 28, 2024. (ii) CFM Service Bulletin LEAP-1C-72-00-0124-01A-930A-D, Issue 001-00, dated September 5, 2024. (3) For CFM material identified in this AD, contact CFM, GE Aviation Fleet Support, 1 Neumann Way, M/D Room 285, Cincinnati, OH 45215; phone: (877) 432-3272; email: aviation.fleetsupport@ge.com. (4) You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 1200 District Avenue, Burlington, MA 01803. 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 January 30, 2025. Suzanne Masterson, Deputy Director, Integrated Certificate Management Division, Aircraft Certification Service. [FR Doc. 2025-02204 Filed 2-3-25; 8:45 am]BILLING CODE 4910-13-P