What was found
ENTIRE CREW SMELLED MUSTY DIRTY LAUNDRY ODOR ON DESCENT TO LANDING YURNING OFF PACK 2 CAUSED ODOR TO DISSIPATE AT 30,000, ODOR RETURNED AT 6000. PACK 2 OFF DIDNT HELP AS MUCH-PERFORM TROUBLESHOOTING IAW TSM 05-50-00-810-831-A, PACK 2 CONFIRMED AS SOURCE OF ODOR. PACK 1 OPS NORMAL WITHOUT ODOR. AIRCRAFT OK FOR SERVICE. MOC # 70473. DESCRIPTION OF ODOR/FUMES: DIRTY SOCKS, MUSTY DRY, MOLDY, UNFAMILIAR CHEMICAL. TEMPORARY. APPARENT CABIN SOURCE: CABIN AIR SUPPLY VENTS. FLIGHT DECK, FWD CABIN/GALLED(LAV), MID CABIN, AFT CABIN/GALLEY(LAV). NO VISIBLE SMOKE/HAZE. NO MEDICAL ATTENTION REQUIRED.