What was found
(CAN) AIRCRAFT WAS IN A CRUISE ATTITUDE, IN PREPARATION TO DISEMBARK SKYDIVERS, WHEN PILOT NOTICED AN ENGINE VIBRATION FOLLOWED BY A BANG, ENGINE CAME TO A SUDDEN STOP. AIRCRAFT LANDED AT AIRPORT OF DEPARTURE WITHOUT FURTHER INCIDENT. UPON INSPECTION, FOUND CRANKSHAFT HAD FAILED AND PUNCTURED THROUGH THE TOP OF THE CRANKCASE. THIS AIRCRAFT ENGINE HAS BEEN MODIFIED PER STA NR SA95-55 AND SE95-9.