As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT MAGNETO INTERNAL GEAR FAILURE. LESS THAN 200 HRS SINCE LAST MAGNETO OVERHAUL. THIS IS THE THIRD TIME ON SAME AIRCRAFT THAT THE LEFT MAGNETO HAS FAILED PRIOR TO SCHEDULED 500 HR INSPECTION, DUE TO PLASTIC DISTRIBUTOR GEAR STRIPPING/BROKEN TEETH. MAGNETO FAILURE FOUND PRIOR TO FLIGHT DURING PREFLIGHT RUN-UP. (NOTE: AIR CONDITIONER DRIVE SHARED BY LEFT MAGNETO DRIVE ON ACCESSORY CASE GEAR TRAIN).