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Notice of proposed rulemaking (NPRM).

We propose to adopt a new airworthiness directive (AD) for certain CFM International S.A. (CFM) CFM56-5B turbofan engines. This proposed AD was prompted by reports of the failure of the radial drive shaft (RDS) on CFM CFM56-5B engines. This proposed AD would require removal of the RDS assembly and the RDS outer housing and their replacement with parts eligible for installation. We are proposing this AD to prevent failure of the RDS, which could lead to failure of one or more engines, loss of thrust control, and damage to the airplane.

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