Airworthiness Directive · Amendment 39-22927 · Turbine section
CFM International, S.A. Engines
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.
The FAA is adopting a new airworthiness directive (AD) for certain CFM International, S.A. (CFM) Model LEAP-1A and LEAP-1C engines. 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. This AD requires removal from service and replacement of the HPT rotor interstage seal for LEAP-1A engines. Since the HPT rotor interstage seal part number is interchangeable between LEAP-1A and LEAP-1C engines, this AD also prohibits installation of these affected parts onto any LEAP-1A or LEAP-1C engine. The FAA is issuing this AD to address the unsafe condition on these products.
(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.
| 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.
(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.
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.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
