What was found
AIRCRAFT DEPARTED SALT LAKE CITY FOR ST GEORGE, UT. DURING CLIMB, ENGINE BEGAN RUNNING VERY POORLY. ENGINE WAS FEATHERED. AIRCRAFT MADE UNEVENTFUL LANDING. INSPECTION OF ENGINE FOUND NR 5 CYLINDER ASSY FAILED. PISTON CONDITION VERY BAD. PRE-IGNITION ON VERY LEAN BURN SUSPECTED. NO PREVIOUS REPORTS OF PROBLEMS OF THAT NATURE.