What was found
DURING THE INITIAL DESCENT FROM 4500 FT CRUISING ALTITUDE, ACFT SUFFERED A PRESSURE LOSS TO THE OIL SUPPLY IN ENGINE NR 1. WE WERE APPROX EIGHT MINUTES FROM LANDING. THE OIL PRESSURE INDICATION FLICKERED TO A YELLOW CAUTION MOMENTARILY. THE NFP CHECKED THE EMERGENCY CHECK LIST FOR THE CORRECT ACTION WHILE THE FP EXECUTED A COURSE REVERSAL. THE PRESSURE CONTINUED TO DROP AND A CAS MESSAGE AND AURAL WARNING WAS ANNOUNCED. WE CARRIED OUT AN INFLIGHT SHUTDOWN OF THE NR 1 ENGINE IAW THE CHECKLIST, AFTER ESTABLISHING OEI FLIGHT AT 2700 FEET. (K)