Action
Final rule.
Summary
We are adopting a new airworthiness directive (AD) for certain CFM International, S.A. model CFM56-5B series turbofan engines. This AD was prompted by a normal quality sampling at CFM International, S.A. that isolated a production batch of fan blades with nonconforming geometry of mid-span shroud tips of the fan blades. This AD requires removing from service certain serial number (S/N) fan blades. We are issuing this AD to prevent an inflight shutdown (IFSD) of one or more engines following foreign object damage (FOD) or a bird strike.