As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) ON RUN UP MAGNETO CHECK, FOUND LT MAG INOP. LT MAG REMOVED AND INSPECTED, ROTOR GEAR WAS FOUND SEPARATED FROM ROTOR SHAFT. RT MAGNETO WAS INSPECTED IN THE SAME AREA OF LT MAG FAILURE NO DEFECT FOUND. A NEW MAGNETO WAS INSTALLED IN LT POSITION RT MAGNETO REINSTALLED. MAGNETOS TIMED TO ENGINE AIRCRAFT GROUND RUN FUNCTION CHECK-SERVICEABLE.