What was found
DESCENDING THROUGH 8000" FUMES WERE NOTICED. PACKS 1 & 2 TURNED OFF- SMELL WENT AWAY. ON THE GROUND WE TURNED APU BLEED W/PACK 1 THE SMELL RETURNED. WITH PACK 2- NO ODOR. DESCRIPTION OF ODOR/FUMES: TEMPORARY, DIRTY SOCKS SMELL. APPARENT CABIN SOURCE: CABIN AIR SUPPLY VENTS. FLIGHT DECK. NO VISIBLE SMOKE/HAZE. NO MEDICAL ATTENTION REQUIRD.-PERFORMED TSM 05-50-00-810-831-A FOUND ODOR ONLY WHEN PACK 1 SELECTED. NO ODOR WHEN PACK 2 SELECTED [APU,ENGINES] C/W AMM 21-00-00-615-803-A LEVEL B CONTAMINATION REMOVAL. SEE ITEM 3535500-2 FOR PACK 1 DEFERRAL