What was found
FUME EVENT IN AIRCRAFT DURING APPROACH, ONLY DETECTED IN COCKPIT PASSING 4000 FT. TURNED OFF THE A/C PACKS AND OPENED RAM AIR PUT ON OXYGEN MASKS, NO FURTHER FUMES DETECTED. INSPECTION PERFORMED TSM 05-50-00-810-831-A. RAN APU WITH BOTH PACKS, NO ODOR PRESENT. FOUND EVIDENCE OF OIL BY THE NR 1 ENGINE DEOILER AREA. RAN ENGINE. NO ODOR OR EVIDENCE OF OIL IN DEOILER AREA AFTER ENG RUN. CLEANED THE AREA OR THE NR 1 DEOILER AREA BEFORE ENGINE RUN.