As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT RIGHT ALTERNATOR DROPPED OFF LINE IN FLIGHT. PILOT RETURNED TO AIRPORT WITHOUT INCIDENT. REMOVED ALTERNATOR AND DISCOVERED DRIVE SHAFT SHEARED. THIS AIRCRAFT HAS THE SINGLE PIECE COUPLING INSTALLED. WHEN SHAFT SHEARS WE HAVE SEEN PIECES CONTAMINANT OIL SYSTEM AND SUBSEQUENTLY CAUSE OIL PUMP FAILURES.