What was found
DURING CRUISE FLIGHT, CREW NOTICED NR 1 ENG OIL PRESSURE DECREASING FROM 42 PSI TO 35 PSI. CREW REDUCED POWER ON NR 1 ENGINE AND CONTINUED TO MONITOR OIL PRESSURE. WHEN OIL PRESSURE DROPPED TO 30 PSI CREW SHUTDOWN NR 1 ENGINE AND DIVERTED TO NEAREST AIRPORT. INSPECTED NR 1 ENG. FOUND O-RING ON OIL FILLER TUBE CUT RESULTING IN A LOSS OF OIL. CONTACTED TECH SUPPORT FOR ENGINE INSP REQUIREMENTS DUE TO LOW OIL PRESSURE AND OIL LOSS. LOCAL MX INSPECTED OIL FILTER FOR METAL IAW TECH SUPPORT. NO DEFECTS NOTED. REPLACED DAMAGED O-RING AND LEAK CHECKED ENGINE.