What was found
(CAN) LIAT, OPERATOR MAINTENANCE CONTROL REPORT:AFTER TAKEOFF, PORT ENGINE TORQUE, STARTED TO FLUCTUATE UNCONTROLLABLY. POWER LEVER WAS RETARDED TO AVOID OVER-TORQUE CONDITION, FLUCTUATIONS CONTINUED, AND PORT CONDITION LEVER WAS MOVED TO START/FEATHER. AIRCRAFT RETURNED TO LAND UNEVENTFULLY. ENGINE REPORT:ON EXAMINATION HBOV GASKET WAS BLOWN, GASKET WAS REPLACED AND EGR CARRIED OUT SATISFACTORY. AIRCRAFT RETURN TO SERVICE.