What was found
ON DESCENT TO HOSPITAL, AS THE PILOT DECREASED COLLECTIVE, THE HIGH RPM AUDIO SOUNDED. HE CHECKED THE RPM INDICATION, AND IT WAS READING 410 (HIGH). HE IMMEDIATELY INCREASED POWER TO THE CRUISE SETTING AND THE RPM RETURNED TO 390 (NORMAL). HE GENTLY TRIED TWICE TO INITIATE THE DESCENT WITH THE SAME RESULTS. HE THEN NOTIFIED AIRCOMM THAT HE WOULD BE DIVERTING TO KMSV TO COMPLY WITH THE EMERGENCY PROCEDURES FOR LANDING. UPON ARRIVAL AT KMSV AND ALIGNED WITH THE RUNWAY, HE COMPLETED THE SLOW RUN-ON LANDING WITHOUT ANY FURTHER ISSUES. THE AIRCRAFT REMAINS OUT OF SERVICE AT THIS TIME AWAITING PARTS (FUEL CONTROL REPLACEMENT).