As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DUE TO OTHER IMPULSE COUPLING FAILURES, AT EVERY 100 HR INSPECTION, THE LT MAGNETO IS REMOVED AND THE IMPULSE COUPLING IS INSPECTED. THIS IMPULSE COUPLING HAD A LOOSE RIVET THAT HOLDS ONE OF THE PAWLS IN PLACE. HAD THE RIVET FAILED THE PAWL WOULD CONTAMINATE THE ENGINE WITH METAL. THE 100 HR INSPECTION INTERVAL WILL CONTINUE ON THE LT MAGNETO.