As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MAGNETO WAS REMOVED FROM ACFT FOR ROUTINE 500 HR MAGNETO INSP. DURING INSP, DISTRIBUTOR GEAR WAS FOUND TO BE MISSNG A FEW TEETH. THE ELECTRODE WAS LOOSE IN THE DISTRIBUTOR GEAR AND HAD WORN THE DISTRIBUTOR BLOCK ELECTRODE POSTS. BOTH PARTS WERE REPLACED. THERE IS NO INDICATION WHAT CAUSED THE TEETH TO BE BROKEN OFF OR THE ELECTRODE TO BECOME LOOSE. THERE WAS NO INDICATION DURING PRE-INSPECTION RUN-UP THAT THERE WAS A PROBLEM WITH THE MAGNETO INTERNAL COMPONENTS.