As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING A TOUR FLIGHT, THE HIGH RPM HORN CAME ON (INTERMITTENLY) IN FLIGHT WITH THE ROTOR RPM IN THE GREEN. AFTER LANDING BACK AT HOME BASE, MAINTENANCE TROUBLESHOT THE INTERMITTENT PROBLEM. AFTER REPLACING THE ROTOR TACHOMETER TRANSDUCER, THE PROBLEM DID NOT REOCCUR. (K)