What was found
NUMBER 5 CYLINDER ON O-470 ENGINE WITH APPROXIMATELY 300 HOURS EXPERIENCED PISTON FAILURE DUE TO WHAT APPEARS AT FIRST IMPRESSION DETONATION. HOWEVER, PISTON IS BELIEVE TO HAVE FAILED DUE TO FLAW IN MANUFACTURE OR EXPERIENCE DAMAGE SUCH AS DROPPING PRIOR TO INSTALLATION IN ENGINE. IT IS MY BELIEF THAT THIS FAILURE OCCURED OVER A PERIOD OF SEVERAL HOURS BY COMBUSTION GASES SLOWLY ERRODING EDGE OF PISTON TO THE POINT OF FAILURE OF PISTON TO OPERATE NORMALLY WITHOUT PASSING OIL AND GASOLINE INTO INDUCTION SYSTEM THEREBY AFFECTING OTHER CYLINDERS.