What was found
(CAN) UPON SELECTION OF GEAR DOWN, PILOT NOTICED THAT GEAR WOULD NOT EXTEND AND THAT THE CIRCUIT BREAKER HAD POPPED. HE RESET IT AND SELECTED GEAR DOWN AGAIN WITHOUT ANY SUCCESS. PILOT USED EMERGENCY EXTENSION AND LANDED WITHOUT INCIDENT. UPON INSPECTION OF LANDING GEARPOWER PACK MOTOR BY ENGINEER, IT WAS FOUND TO BE SHORTED OUT. MOTOR WAS REPLACED AND EXTENSION/RETRACTION SYSTEM FUNCTIONALLY CHECKED SERVICEABLE.