As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN)ENGINE ROUGH ON RUN UP. MAGNETO SEPARATED FROM ENGINE AND HANGING FROM HARNESS. MAGNETO SEIZED AND MOUNTING FLANGE FRACTURED. ROTOR SHAFT SEIZED DUE TO BEARING FAILURE ENSUING FROM OUTER RACE OF BEARING SPINNING WITHIN THE BEARING CAP ASSEMBLY. BEARING CAP ASSEMBLY LACKED THE "J" MARKING SEPCIFIED IN SB 2-88A ALTHOUGH THIS MAGNETO FALLS INTO THE SERIAL NUMBER RANGE FOR THE SB.