Airworthiness Directive · Amendment 39-22727 · Turbine engine compressor section
CFM International, S.A. Engines
This AD applies to CFM International, S.A. (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, and LEAP-1A35A engines with an installed No. 3 bearing spring finger housing having part number (P/N) 2629M62G01 and a serial number identified in Table 1 or Table 2 of CFM Service Bulletin (SB) LEAP-1A-72-00-0504-01A-930A-D, Issue 002, dated October 17, 2023 (CFM SB LEAP-1A-72-00-0504-01A-930A-D, Issue 002).
The FAA is adopting a new airworthiness directive (AD) for certain CFM International, S.A. (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, and LEAP-1A35A 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). Additional manufacturer investigation revealed that wear on the No. 3 bearing spring finger housing can lead to high levels of NSV. This AD requires initial and repetitive calculations of the levels of NSV, inspection of the stage 2 high-pressure turbine (HPT) nozzle assembly honeycomb and HPT stator stationary seal honeycomb and, depending on the results of the calculations and inspections, replacement of certain parts. This AD also requires replacement of certain No. 3 bearing spring finger housings at a certain time. The FAA is issuing this AD to address the unsafe condition on these products.
(1) Within 125 flight cycles (FCs) after the effective date of this AD and thereafter at intervals not to exceed 125 FCs, calculate the NSV data in accordance with the Accomplishment Instructions, paragraphs 5.A.(1) and 5.A.(3), or 5.B.(1) and 5.B.(3) of CFM SB LEAP-1A-72-00-0504-01A-930A-D, Issue 002.
(2) If, during any calculation required by paragraph (g)(1) of this AD, the NSV data exceeds the limits specified in the Accomplishment Instructions, paragraph 5.A.(4)(a)1 or 5.B.(4)(a)1 of CFM SB LEAP-1A-72-00-0504-01A-930A-D, Issue 002, discontinue the calculations required by paragraph (g)(1) of this AD and within 150 FCs of the flight when these limits are exceeded:
(i) Remove from service the No. 3 bearing spring finger housing having P/N 2629M62G01 and a serial number identified in Table 1 or Table 2 of CFM SB LEAP-1A-72-00-0504-01A-930A-D, Issue 002, and replace with a part eligible for installation.
(ii) Inspect the stage 2 high-pressure turbine (HPT) nozzle assembly honeycomb for rubs in accordance with the Accomplishment Instructions, paragraphs 5.A.(4)(a)3b1) or 5.B.(4)(a)3b1) of CFM SB LEAP-1A-72-00-0504-01A-930A-D, Issue 002.
(iii) Inspect the HPT stator stationary seal honeycomb for rubs in accordance with the Accomplishment Instructions, paragraphs 5.A.(4)(a)3b2) or 5.B.(4)(a)3b2) of CFM SB LEAP-1A-72-00-0504-01A-930A-D, Issue 002.
(3) If, during the inspection required by paragraph (g)(2)(ii) of this AD, the stage 2 HPT nozzle assembly honeycomb fails to meet the serviceability criteria referenced in the Accomplishment Instructions, paragraphs 5.A.(4)(a)3b1) or 5.B.(4)(a)3b1) of CFM SB LEAP-1A-72-00-0504-01A-930A-D, Issue 002, before further flight, replace the stage 2 HPT nozzle assembly honeycomb.
(4) If, during the inspection required by paragraph (g)(2)(iii) of this AD, the HPT stator stationary seal honeycomb fails to meet the serviceability criteria referenced in the Accomplishment Instructions, paragraphs 5.A.(4)(a)3b2) or 5.B.(4)(a)3b2) of CFM SB LEAP-1A-72-00-0504-01A-930A-D, Issue 002, before further flight, replace the HPT stator stationary seal.
(5) At the next piece-part exposure after the effective date of this AD, but before exceeding 9,900 cycles since new, replace the No. 3 bearing spring finger housing having P/N 2629M62G01 and a serial number identified in Table 1 of CFM SB LEAP-1A-72-00-0504-01A-930A-D, Issue 002, with a part eligible for installation.
Replacement of the No. 3 bearing spring finger housing having P/N 2629M62G01 and a serial number identified in Table 1 or Table 2 of CFM SB LEAP-1A-72-00-0504-01A-930A-D, Issue 002 with a part eligible for installation, as specified in paragraphs (g)(2)(i) and (g)(5) of this AD, constitutes terminating action for the calculations required by paragraph (g)(1) of this AD.
For the purpose of this AD, a “part eligible for installation” is a No. 3 bearing spring finger housing that does not have P/N 2629M62G01 and a serial number identified in Table 1 or Table 2 of CFM SB LEAP-1A-72-00-0504-01A-930A-D, Issue 002.
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.
