What was found
DURING CRUISE FLIGHT, A LOUD BANG FROM THE ENGINE COMPARTMENT WAS FOLLOWED BY LOSS OF POWER AND SIGNIFICANT ENGINE VIBRATION. THE PILOT MADE AN EMERGENCY LANDING ON A DIRT ROAD WITH NO DAMAGE TO THE AIRCRAFT. THE NR 1 CYLINDER HEAD HAD FRACTURED COMPLETELY THROUGH, JUST ABOVE THE CYLINDER BARREL THREADS, LEAVING A .5 INCH GAP BETWEEN HEAD FINS 6 AND 7. THE CYLINDER HAD BEEN REPAIRED 212 HOURS PRIOR TO FAILURE AND HAD BEEN BORED TO .010 OVERSIZE. A SERVICEABLE TAG HAD BEEN PROVIDED BY THE REPAIR STATION THAT PERFORMED THE WORK. (K)