What was found
(CAN) WHILE ON APPROACH FOR LANDING, A HIGH ROTOR SPEED CONDITION OCCURED. THE PILOT IMMEDIATELY NOTICED THE INCREASE IN NR AND INCREASED COLLECTIVE TO MAINTAIN THE NR WITHIN NORMAL PARAMETERS. WITH THE NR STABILIZED, THE DEFECTIVE ENGINE WAS IDENTIFIED AND THE THROTTLE CONTROL LEVER WAS RETARDED. THE AIRCRAFT DESCENDED AND CARRIED OUT AN UNEVENTFUL LANDING. ONCE ON THE GROUND, A SEPARATE ENGINE CHECK IDENTIFIED THE NR 2 ENGINE FCU NF GOVERNOR HAD FAILED. THE FUEL CONTROL UNIT WAS REPLACED.