What was found
LT ENGINE OIL FILTER MESSAGE DISPLAYED. MESSAGE REMAINED WHEN THRUST REDUCED & ENG SHUTDOWN. NR 1 ENG OIL PRESSURE LIGHT DID NOT COME ON. C/W FIM 79A-35-00-90, OIL FILTER EICAS MESSAGE WAS NOT DISPLAYED AT AIRCRAFT ARRIVAL THOUGH ENGINE WAS STILL WINDMILLING IN HEADWIND. EXAMINED NR 1 ENGINE OIL STRAINER, NO CONTAMINATION. REPLACED NR 1 ENGINE MAIN OIL SCREEN. EXAMINED THE FULL FLOW MASTER CHIP DETECTOR FOR CONTAMINATION, NONE NOTED. INSPECTED ALL ENGINE AND GEARBOX CHIP DETECTORS WITH NO CONTAMINATION NOTED IAW AMM. C/W ENGINE RUN, NO DEFECTS ON ENGINE RUN AFTER NR 1 FILTER CHANGE. REPLACED DIFFERENTIAL OIL PRESSURE SWITCH ON NR 1 ENGINE. PERFORMED ADJ TEST OF OIL BYPASS WARNING SYSTEM. CHECKED GOOD.