What was found
WHILE ON THE RETURN FLIGHT, CREW EXPERIENCED RT ENGINE ABNORMALITIES. THE TORQUE INDICATION EXCEEDED THE RED LINE LIMITATION AND BECAME UNCONTROLLABLE. AT THE SAME TIME, A DRASTIC DECLINE IN PROP RPM (BELOW 900 RPM) WAS NOTED. BOTH INDICATIONS WERE NOT ADJUSTABLE TO A STABLE CONDITION, THUS THE NECESSITY TO EXECUTE PRECAUTIONARY RT ENGINE SHUTDOWN. AN EMERGENCY WAS ALSO DECLARED. THE AIRCRAFT LANDED WITHOUT INCIDENT. MECHANIC REPLACED PROP GOVERNOR WITH A SERVICEABLE ONE IAW MM. OPS CHECK GOOD AND THE AIRCRAFT WAS RETURNED TO SERVICE. (K)