What was found
MCO/OMA - FLT 800 - ON FLIGHT, NR 1 ENGINE OIL QUANTITY STARTED TO DECREASE ACCOMPANIED BY A DROP IN OIL PRESSURE (TO 30 PSI) FOLLOWED BY THE NR 1 ENGINE OIL PRESSURE LIGHT ON STEADY. POWER WAS REDUCED TO IDLE RPM ON NR 1 ENGINE AND AIRCRAFT WAS DIVERTED TO MCI WHERE A NORMAL LANDING WAS CONDUCTED. MECHANICS INSPECTED NR 1 ENGINE AND FOUND AN O-RING LEAKING AT THE OIL PRESSURE DIFFERENTIAL SWITCH. THE O-RING WAS REPLACED AND THE ENGINE WAS RUN FOR A LEAK CHECK. ALL CONDITIONS CHECKED NORMAL. AIRCRAFT WAS RELEASED FOR FLIGHT. (X)