What was found
(CAN) DURING REVENUE FLIGHT, THE ACFT WAS IN CLIMB WHEN PILOTS GOT A LOW OIL PRESSURE WARNING FOLLOWED BY A DROP IN OIL PRESSURE ON THE INDICATOR. WHEN THE PRESSURE DROPPED BELOW 50 PSI, THE PILOTS PERFORMED A COMMANDED IFSD AND CONTINUED TO THE PLANNED DESTINATION WHERE AN UNEVENTFUL SINGLE ENGINE LANDING WAS ACCOMPLISHED. FOLLOWING TROUBLESHOOTING WITH LOCAL FSR, IT WAS DETERMINED THAT THE CORE ENGINE NEEDS TO BE REMOVED FOR REPAIR.