Summary
The FAA proposes to supersede Airworthiness Directive (AD) 2021-10-09, which applies to all CFM International, S.A. (CFM) CFM56-5B and CFM56-7B model turbofan engines with a certain high-pressure turbine (HPT) inner stationary seal installed. AD 2021-10-09 requires removal, inspection, and replacement of the affected HPT inner stationary seal and, depending on the findings, replacement of the rotating air HPT front seal, HPT rotor blades, and No. 3 ball bearing. Since the FAA issued AD 2021-10-09, the manufacturer notified the FAA that the service information incorrectly lists the year of certain honeycomb repairs. Additionally, the manufacturer notified the FAA that affected HPT inner stationary seals could potentially be installed on CFM CFM56-5C model turbofan engines. This proposed AD would require removal, inspection, and replacement of the affected HPT inner stationary seal and, depending on the findings, replacement of the rotating air HPT front seal, HPT rotor blades, and No. 3 ball bearing. This proposed AD would also revise the applicability to add CFM CFM56- 5C model turbofan engines. The FAA is proposing this AD to address the unsafe condition on these products.