What was found
(CAN) DURING DESCENT, THE OIL PRESSURE WAS SEEN DROPPING BUT REMAINING IN THE GREEN BAND. SHORTLY AFTER, SMOKE ENTERED THE COCKPIT AND CABIN. THE ACFT LANDED SAFELY WITH THE ENGINE RUNNING. IT WAS SHUTDOWN AND THE ACFT TAXIED TO THE GATE. POST FLIGHT INSPECTION FOUND METALLIC DEBRIS IN THE EXHAUST. THE ENGINE WAS REMOVED AND WILL BE SENT FOR INVESTIGATION AND REPAIR.