Summary
This supplemental NPRM revises an earlier proposed airworthiness directive (AD), for certain CFM International, S.A. models CFM56-3 and -3B turbofan engines. That proposed AD would have required initial and repetitive inspections for damage to the fan blades. That proposed AD resulted from a report of a failed fan blade with severe out-of-limit wear on the underside of the blade platform where it contacts the damper. This supplemental NPRM revises the proposed AD to reduce the initial inspection compliance threshold, to correct the engine model designations affected, and to clarify some of the inspection wording in the compliance section. This supplemental NPRM results from a report of a failed fan blade with severe out-of- limit wear on the underside of the blade platform where it contacts the damper. We are proposing this supplemental NPRM to prevent failure of multiple fan blades, which could result in an uncontained failure of the engine and damage to the airplane.