As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING MAINTENANCE TO TROUBLESHOOT A FAILED NR 2 ALTERNATOR, WE NOTICED A THRU-BOLT NUT MISSING FROM NR 4 TOP CYLINDER AND THE THRU-BOLT MIGRATED OUT ONTO THE NR 5 CYLINDER. THE NUT WAS FOUND IN THE BAFFLING BENEATH THE CYLINDER AND IT HAD FAILED BY CRACKING.