As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CYLINDER) FOUND HEAD OF CYLINDER NR6 SEPARATING FROM THE BARREL AT THE THREADED PORTION OF HEAD. VERIFIED ENGINE TIMING WAS CORRECT. NO EVIDENCE OF DETONATION FOUND. AL CYLINDER NEW AT OVERHAUL. AT 570 HOURS NR4 CYLINDER FAIL THE SAME WAY. ALL CYLINDERS HAD SAME DATE CODE 5-99. APPEARS TO BE A MFG DEFECT.