What was found
I HEARD THE ENGINE BACKFIRE A FEW TIMES DURING TAKEOFF/INITIAL CLIMB OUT AROUND 6/20/2025. PLANE WAS BROUGHT TO MAINTENANCE 6/25/2025 FOR REPORTS OF INABILITY TO START THE RH ENGINE. AFTER MULTIPLE STARTING ATTEMPTS, A VISUAL INSPECTION WAS CONDUCTED ON THE ENGINE AND IT WAS FOUND THAT THE RIVETS ON THE PAWLS FOR THE IMPULSE COUPLING HAD SHEARED OFF, TRAPPING THE PAWLS BETWEEN THE IMPULSE COUPLING AND THE MAGNETO CASE, CAUSING THE MAGNETO TO EXIT THE BACK OF THE ENGINE IN PIECES, TAKING PART OF THE SHOULDER ADAPTER WITH IT. PIECES OF THE MAGNETO SPRING, PAWLS, RIVETS, AND OTHER ASSOCIATED METAL DEBRIS WERE FOUND IN THE ACCESSORY CASE AND OIL SUMP.