What was found
NR 2 ENGINE OIL PRESSURE LIGHT CAME ON DIM DURING FLIGHT. COULD EXTINGUISH LIGHT BY RETARDING THRUST TO IDLE INITIALLY. BUT EVENTUALLY CAME ON AT IDLE. OIL TEMP READING 135. QUANTITY DECREASED FROM 4.2 GAL AT T/O. R&R MAIN OIL FILTER, FOUND SOME CARBON BB'S NO METAL. RAN ENG PER JRH 5.2 TO T/O THRUST AND PERFORMED POWER ASSURANCE RUN AFTER PERFORMING LOW POWER LEAK CHECK & ENG OIL PRESS & TEMP CHECK. REEXAMINED MAIN OIL. SCREEN NO FOD FOUND, REINSTALLED & CLOSED ENG TRIM SHEET SENT TO POWERPLANT, PERFORMED BREATHER TEST PER P/W M/M 72-00, CHECKS NORMAL ENG OK FOR SERV. REPLACED NR 2 ENG OIL FILTER BY-PASS SWITCH PER M/M 79-33-2 OPS CHECK & LEAK CHECK SERVICEABLE P/N & S/N ON OFF.