What was found
(CAN) DURING FLIGHT, THE CREW OBSERVED TORQUE FLUCTUATIONS UP TO 2 PERCENT. THE ENGINE WAS SHUTDOWN AND AN UNEVENTFUL SINGLE ENGINE LANDING FOLLOWED. POST FLIGHT TROUBLESHOOTING FOUND NO ANOMALIES. THE PROPELLER CONTROL AND AUTOFEATHER UNIT WERE REPLACED AS PRECAUTIONARY MEASURE, ELECTRICAL CONNECTORS CLEANED BEFORE PERFORMING SATISFACTORY GROUND RUNS. THE ACFT WAS RETURNED TO SERVICE BUT ENCOUNTERED THE SAME PROBLEM ON A SUBSEQUENT FLIGHT FOR WHICH THE ENGINE WAS NOT SHUT DOWN. THE ACFT IS NOW GROUNDED FOR FURTHER TROUBLESHOOTING.