What was found
WHILE EN ROUTE BETWEEN CVG AND PIT, THE CAPTAIN NOTICED A DROP FROM 65 PSI TO 50 PSI IN THE LEFT POEWR SECTION OIL PRESSURE, FLUCTUATING REDUCTION GEARBOX OIL PRESSURE AND A THREE GALLON DROP IN OIL QTY. THE CAPTAIN PULLED THE LEFT 'E' HANDLE AND SECURED THE ENGINE. THE CREW DIVERTED TO THE COLUMBUS MAINTENANCE FACILITY AT LCK. A BROKEN EXTERNAL OIL PRESSURE LINE SERVICING THE NR 4 BEARING WAS REPLACED AND THE AIRCRAFT WAS RETURNED TO SERVICE. THE FAILURE OF THE OIL LINE MAY HAVE BEEN CAUSED BY A VIBRATING REDUCTION GEARBOX THAT HAD RECENTLY BEEN REPLACED ON THAT ENGINE. (M)