As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING CRUISE FLIGHT, THE PILOT NOTICED A CHANGE IN ENGINE NOISE AND A SLIGHT YAW FOLLOWED BY THE LOW ROTOR HORN. PILOT DECREASED POWER WHICH RESULTED IN THE ROTOR RPM RECOVERING TO A NORMAL SETTING. THE PILOT FINISHED THE SHORT FLIGHT AT A LOWER POWER SETTING AND LANDED THE AIRCRAFT WITHOUT FURTHER INCIDENT. AFTER LANDING, A MAGNETO CHECK WAS CONDUCTED WHICH RESULTED IN THE ENGINE QUITING WHEN THE R/H MAG WAS SELECTED. WHEN THE MAGNETO WAS REMOVED, A FEW TEETH WERE FOUND BROKEN OFF THE DISTRIBUTOR GEAR.