What was found
(CAN) AIRCRAFT HAD TO SHUTDOWN THE RT ENGINE DURING FLIGHT, DUE TO LOW OIL PRESSURE. APPROX 3 HOURS INTO THE FLIGHT, THE PILOT REPORTED THE OIL PRESSURE WAS FLUCUTATING BETWEEN 45 AND 65 PSI, THEN DROPPED AGAIN TO 35 AND 55 PSI, AND FINALLY GOT A STEADY LOW OIL PRESSURE LIGHT. THIS IS WHEN THE PILOT SHUTDOWN THE RT ENGINE, AND DIVERTED. AN INSPECTION REVEALED THE RT ENGINE WAS 4 QTS LOW ON OIL. THE PILOTS HAD ALREADY SERVICED THIS ENGINE WITH 2 QTS, PRIOR TO LEAVING. APPEARS THE AIRCRAFT USED 4 QTS OF OIL IN THAT 3 HOUR PERIOD. AN OIL CONSUMPTION CHECK WAS PERFORMED, AND WAS FOUND TO BE WITHIN LIMITS. THE AIRCRAFT IS UNDERGOING FURTHER TROUBLESHOOTING. (TC NR 20060728006)