What was found
PILOT REPORTED SLIGHT OIL ODOR WITH APU SUPPLYING BLEED PRESSURE FOR PACKS ON TAXI IN. SMELL DISSAPATED QUICKLY AFTER ARRIVAL AT GATE. FLIGHT CREW REPORTED NO ODORS DURING ANY PHASE OF PREVIOUS FLIGHT. INSPECTED APU BLEED DUCT FOR EVIDENCE OF OIL LEAKAGE. NO EVIDENCE OF OIL LEAKAGE FOUND AT THIS TIME, DUCT CLEAR OF DEBRIS. INSPECTED LEFT AND RIGHT PACK BLEED AIR SUPPLY DUCTS FOR EVIDENCE OF OIL INTRUSTION. NO EVIDENCE OF OIL CONTAMINATION FOUND AT THIS TIME, DUCTS CLEAR OF ANY DEBRIS. REMOVED AND REPLACED BOTH RECIRCULATION AIR FILTERS. PERFORMED LEAK CHECK OF APU BLEED AND BOTH PACK BLEED AIR SUPPLY DUCTS. LEAK CHECKED GOOD.