What was found
(CAN) OIL PRESSURE LOSS/IFSD DURING CRUISE, THE OIL PRESSURE AND OIL TEMPERATURE STARTED TO FLUCTUATE. THE PILOT ELECTED TO RETARD THE POWER TO FLIGHT IDLE APPROXIMATELY 50 MILES OUT OF GRAND JUNCTION. OIL PRESSURE FLUCTUATIONS WERE FOLLOWED BY LOW OIL PRESSURE WARNING LIGHT. THE ENGINE WAS SHUT DOWN AND SECURED BEFORE THE A/C LANDED (WITHOUT INCIDENT) IN GRAND JUNCTION. TROUBLESHOOTING FOUND AN OIL LEAK AT NR 4 BEARING OIL TRANSFER TUBE.