What was found
(CAN) SHORTLY AFTER TAKE OFF FROM FORT SMITH THE OIL PRESSURE INDICATION ON THE LT ENGINE DROPPED TO ZERO AND THE OIL PRESSURE LIGHT CAME ON. A PRECAUTIONARY SHUTDOWN WAS CARRIED OUT AND THE A/C RETURNED TO FORT SMITH. ON INVESTIGATION IT WAS DISCOVERED THAT A WIRE BUNDLE WAS CHAFING ON THE NACELLE UPPER DOOR NEAR THE OIL PRESSURE TRANSMITTER. THE WIRES WERE CHAFED RIGHT THROUGH TO BARE WIRE AND THEY SHORTED TO THE DOOR.THIS CAUSED THE OIL PRESSURE INDICATION TO DROP OFF, AS IF THE ENGINE HAD LOST PRESSURE SUDDENLY.