Airworthiness Directive · Amendment 39-22413 · Turbine engine compressor section
CFM International, S.A. Engines
This AD applies to CFM International, S.A. (CFM) Model LEAP-1B21, LEAP-1B23, LEAP-1B25, LEAP-1B27, LEAP-1B28, LEAP-1B28B1, LEAP-1B28B2, LEAP-1B28B2C, LEAP-1B28B3, LEAP-1B28BBJ1, and LEAP-1B28BBJ2 engines with an installed No. 3 bearing spring finger housing, part number 2542M54G01, and serial number identified in Table 1 of CFM Service Bulletin LEAP-1B-72-00-0369-01A-930A-D, Issue 001-00, dated August 22, 2022 (CFM SB LEAP-1B-72-00-0369-01A-930A-D).
The FAA is adopting a new airworthiness directive (AD) for certain CFM International, S.A. (CFM) Model LEAP-1B engines. This AD was prompted by a report of multiple aborted takeoffs and air turn- backs (ATBs) caused by high-pressure compressor (HPC) stall, which was induced by high levels of non-synchronous vibration (NSV). A subsequent investigation by the manufacturer revealed that wear on the No. 3 bearing spring finger housing can lead to high levels of NSV. This AD requires repetitive calculations of the oil filter delta pressure (OFDP) data and, depending on the results of the calculation, replacement of the No. 3 bearing spring finger housing. This AD also prohibits installation of an engine with an affected No. 3 bearing spring finger housing onto an airplane that already has one engine with an affected No. 3 bearing spring finger housing installed. The FAA is issuing this AD to address the unsafe condition on these products.
(1) Before the affected No. 3 bearing spring finger housing accumulates 125 flight cycles (FCs) since new, but not before accumulating 75 FCs since new, or within 50 FCs after the effective date of this AD, whichever occurs later, calculate the oil filter delta pressure (OFDP) data in accordance with the Accomplishment Instructions, paragraphs 5.A.(1) through 5.A.(2) or 5.B.(1) through 5.B.(2), of CFM SB LEAP-1B-72-00-0369-01A-930A-D.
(2) Thereafter, at intervals not to exceed 100 FCs from the last calculation of the OFDP data, and until the affected No. 3 bearing spring finger housing accumulates 1,000 FCs since new, repeat the calculation required by paragraph (g)(1) of this AD.
(3) If, during the calculation required by paragraph (g)(1) or (2) of this AD, the OFDP data exceed the limits specified in the Accomplishment Instructions, paragraph 5.A.(3) or 5.B.(3), of CFM SB LEAP-1B-72-00-0369-01A-930A-D, as applicable, within 25 FCs of performing the calculation, replace the affected No. 3 bearing spring finger housing with a part eligible for installation.
(4) During the next engine shop visit after the effective date of this AD, replace the affected No. 3 bearing spring finger housing with a part eligible for installation.
Replacement of the affected No. 3 bearing spring finger housing with a part eligible for installation, as specified in paragraphs (g)(3) and (4) of this AD, constitutes terminating action for the calculations required by paragraphs (g)(1) and (2) of this AD.
After the effective date of this AD, do not install an engine with an affected No. 3 bearing spring finger housing onto an airplane that already has one engine with an affected No. 3 bearing spring finger housing installed.
(1) For the purpose of this AD, a “part eligible for installation” is a No. 3 bearing spring finger housing that is not identified in Table 1 of CFM SB LEAP-1B-72-00-0369-01A-930A-D.
(2) For the purpose of this AD, an “engine shop visit” is the induction of an engine into the shop for maintenance involving the separation of pairs of major mating engine flanges. The separation of engine flanges solely for the purpose of transportation without subsequent engine maintenance does not constitute an engine shop visit.
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.
