As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING ROUTINE 500 HOUR INSPECTION, DISCOVERED IMPULSE COUPLING CRACKED AT FULL ADVANCE STOP ON FLYWEIGHT BASE PLATE. CRACKS DETECTED USING MAGNETIC PARTICLE NDT METHOD. HAVE SEEN THIS SAME ISSUE WITH MANY OTHER MAGNETOS. CRACKS APPEAR TO BE ORIGINATING FROM A SHARP CORNERED FEATURE OF THE BASE PLATE. RECOMMEND DESIGN CHANGE TO INCLUDE A SMALL RADIUS IN THAT CORNER TO REDUCE STRESS RISER/CRACKING ISSUES.