As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) A PIECE OF COTTER PIN WAS FOUND ON THE ENGINE MAGNETIC DRAIN PLUG. REMOVED R/H MAGNETO AND FOUND PART OF THE COTTER PIN HOLDING THE MAGNETO DRIVE WAS MISSING AND MATCHED THE PIECE THAT WAS FOUND IN THE OIL SUMP. A NEW COTTER PIN WAS INSTALLED, THE MAGNETO REINSTALLED AND RETURNED TO SERVICE.