What was found
ON APPROACH, CREW REPORTED THE NR 1 PROP RPM INCREASE TO MAX RPM AND WOULD NOT CONTROL ENGINE SPEED. THE ENGINE WAS SHUT DOWN PRECAUTIONARY AND THE AIRCRAFT LANDED WITHOUT INCIDENT. NO EMERGENCY WAS DECLARED. ON LANDING INSPECTION OF THE PROPELLER INDICATED LOW FLUID LEVEL DUE TO DEFECTIVE O-RING ON THE SERVICING PLUG. OIL LEVEL WAS RESERVICED AND ENGINE PERFORMANCE RUN ACCOMPLISHED. PROPELLER FAILED TO CONTROL RPM. TROUBLESHOOTING INDICATED FAILURE OF THE PROP REGULATOR INTERNAL PUMPS. UNIT WILL BE SENT TO O/H FACILITY TO DETERMINE CAUSE OF THE FAILURE. THE LT PROPELLER REGULATOR WAS REMOVED AND REPLACED SEPT20, 2006 AND THE AC RETURNED TO SERVICE. (K)