As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING AN ANNUAL INSPECTION, THE BOTTOM CRANKCASE THROUGH-BOLT LOCATED BETWEEN NR 1 AND NR 3 CYLINDER POSITION WAS FOUND BACKED OUT FROM THE CASE ALMOST TO THE POINT OF FALLING OUT OF ITS MOUNTING HOLE BY APPROXIMATELY 1.1250 INCHES. WHEN BOLT WAS REMOVED, FOUND THE OTHER END AT THE THREADED PORTION MISSING FROM BEING BROKEN OFF. NO OIL LEAK WAS PRESENT. NO OTHER CASE BOLTS OR CYLINDER STUDS WERE AFFECTED FROM THIS OCCURRENCE.