As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON A 500 HOUR MAGNETO INSPECTION, FOUND MAGNETO SPARKING INTERNALLY. AC RAN GOOD AND HAD A 100 RPM MAG DROP. INTERNAL SPARKING WAS BETWEEN COIL AND CARBON BRUSH. BRUSH AND SPRING DESTROYED AND PART OF DISTRIBUTOR BLOCK MISSING. RECOMMEND MANDATORY INTERNAL INSPECTION OF MAGNETOS DURING ANNUAL. NEED TO ADD FARS. (K)