What was found
AFTER TAKEOFF, SMELLED AND VISUALLY SAW SMOKE IN COCKPIT ENTERED FROM VENT LOUVERS. ODOR DISSIPATED AFTER APPROX 2 MIN. PERFORMED AIR RETURN AND LANDED AT 44,000 LBS, NORMAL LANDING. INSPECTED APU AND PACKS. NO DEFECTS FOUND. INSPECTED DE-ICE FLUID INGESTION INTO INLET OF APU OR PACKS. PERFORMED GROUND RUN AND TEST OF ENVIRONMENTAL SYSTEM WITH ENGINES AND APU BLEEDS. NO DEFECTS FOUND REF AMM 21-61-01.