As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT COMPLAINED RT ENGINE WAS ROUGH RUNNING. FOUND NR 1 CYLINDER HELD ON BY ONLY AFT TWO THROUGH-BOLTS. ALL OTHER MOUNT STUDS WERE BROKEN. REMOVED CYLINDER AND THROUGH-BOLTS. PENETRATE CHECK OF CASE MOUNTING AREA REVEALED TWO CRACKS (1 O'CLOCK AND 7 O'CLOCK) AT MOUNT STUD HOLES AND MAG PARTICLE OF THROUGH-BOLTS REVEALED ONE CRACKED.