What was found
(CAN) NR 3 CYLINDER PISTON EXPERIENCED FAILURE OF ITS ALUMINUM SIDE DURING CRUISE FLIGHT, RESULTING IN ENGINE POWER LOSS AND ROUGH OPERATION. PISTON FAILURE CAUSED PRESSURE FROM COMBUSTION TO ENTER THE CRANKCASE. THIS RESULTED IN THE CRANKCASE BECOMING PRESSURIZED FORCING THE ENGINE OIL TO BE DUMPED OVERBOARD THROUGH THE CRANKCASE BREATHER TUBE. OIL PRESSURE WAS EVENTUALLY LOSS RESULTING IN AN ENGINE STOPPAGE IN FLIGHT. EMERGENCY LANDING ISSUED WITH NO FURTHER DAMAGE.