What was found
(CAN)INVESTIGATION OF #1 ENGINE OIL LEAK FOUND OIL FLOW AT THRUST BEARING (CRANKSHAFT). ENGINE MOTORING INDICATED NO CYLINDER BLOW BY. PROPELLER REMOVED AND CRANKSHAFT CAPPED, ACTUATION OF FEATHERING PUMP INDICATED LOSS OF OIL THROUGH AN ANNULAR CRACK STARTING IN THE THRUST BEARING NUT RETENTION THREADS AND COMING FORWARD UNDER THE PROP CONE AREA. THE SHAFT WAS CRACKED MORE THAN 270 DEGREES OF THE CRANKSHAFT CIRCUMFERENCE.