What was found
AT CRUISE FLIGHT, AFTER 1 HR 27 MIN INTO FLIGHT, THE LT OIL PRESSURE INDICATOR FLUCTUATED FROM APPROXIMATELY 42-45 PSI DOWN TO 30-35 PSI TWICE PER SECOND CONTINUOUSLY. OIL TEMP REMAINED NORMAL, ALL OTHER ENGINE INDICATIONS NORMAL, (N1, ITT, N2). APPROXIMATELY 4-6 MINUTES LATER THE OIL PRESSURE INDICATOR FLUCTUATED DOWN TO 25-35 PSI, THE LT ENGINE "OIL PRESS LOW" ANNUCIATOR ILLUMINATED. THE SIC REDUCED POWER TO IDLE, EXECUTED SHUTDOWN PROCEDURES IAW CHECKLIST PROCEDURE. THE PIC DECLARED AN EMERGENCY AND DIVERTED . THE LT ENGINE OIL FILTER BYPASS INDICATOR WAS FOUND POPPED, METAL PIECES WERE FOUND IN THE FILTER AND TRANSFER GEARBOX, AND THE NR 6 BEARING, OIL PRESSURE LINE WAS FOUND CRACKED. (K)