Action
Notice of proposed rulemaking (NPRM).
Summary
The FAA proposes to supersede Airworthiness Directive (AD) 2019-12-05, which applies to certain CFM International S.A. (CFM) CFM56-5B, CFM56-5C, and CFM56-7B model turbofan engines with a certain rotating air high-pressure turbine (HPT) front seal. AD 2019-12-05 requires replacement of the affected rotating air HPT front seal with a part eligible for installation. The actions required by AD 2019-12-05 are interim and only address the highest risk engines with an affected rotating air HPT front seal that have a specified number of cycles since being reconfigured. This proposed AD would require removal and replacement of the rotating air HPT front seals installed on all CFM CFM56-5B, CFM56- 5C, and CFM56-7B model turbofan engines, including engines that have fewer cycles since being reconfigured. The FAA is proposing this AD to address the unsafe condition on these products.