As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
COMPLETE FAILURE OF THE RT MAGNETO ON THE RT ENGINE. THIS COMPLETE FAILURE OCCURRED TWICE WITH TWO MAGNETOS. THE FIRST MAGNETO (SN 02071564) FAILED WITH A TOTAL TIME OF 529.1. THE SECOND MAGNETO (SN 04041941) FAILED WITH A TOTOAL TIME OF 166.6. BOTH FAILURES WERE THE RESULT OF THE ANTI-DRIVE END OF THE ROTOR, SHEARING OFF BELOW THE ROTOR GEAR(M3827) AT THE BASE OF THE CAM SLOT.