What was found
ACFT WAS INSPECTED, ENGINE GROUND WAS CARRIED OUT BOTH ENGINE PERFORMANCE WAS GOOD. AT THE TIME OF FERRYING ACFT UNDER THE FERRY FLIGHT PERMIT WHEN ACFT FLEW AND CRUISE AT 10,000 FEET ALTITUDE. RT PROPELLER WAS NOT RESPONDING WITH THE THE PROPELLER LEVER MOVEMENT. ACFT DIVERTED AND LANDED BACK TO DEPARTURE. PROPELLER GOVERNOR REPLACED WITH NEWLY OH GOVERNOR WITH SN:8911344P AND OPERATION CHECK GOOD. ACFT WILL BE FLIGHT TESTED AT 10,000 FEET ALTITUDE BEFORE COMMENCING FERRY.