Airworthiness Directives; Certain Textron Lycoming 320 and 360 Series Reciprocating Engines

This amendment adopts a new airworthiness directive (AD), applicable to certain Textron Lycoming 320 and 360 series reciprocating engines, that requires visual inspections of the inside diameter (ID) of the crankshaft for corrosion pits, and if corrosion pits are found during this inspection, prior to further flight, performing a magnetic particle inspection (MPI) or fluorescent penetrant inspection (FPI) of the ID for cracks. In addition, this AD requires reporting findings of inspections to the FAA. Finally, terminating action to the inspections of this AD is the application of a preventive treatment coating on non- corroded crankshafts to prevent corrosion. This amendment is prompted by reports of cracks in crankshafts originating from corrosion pits in the ID. The actions specified by this AD are intended to prevent crankshaft failure, which can result in engine failure, propeller separation, forced landing, and possible damage to the aircraft.