What was found
FUME EVENT DESCENDING THRU 4000 AND CONTINUED TO GATE-APPLIED TSM 05-50-00 PERFORMED BURNOUT OF PACK 1. R&R RECIRC FILTERS IAW AMM 21-21-41. NO ODOR PRESENT ON PACK 1 AT THIS TIME. DESCRIPTION OF ODOR/FUMES: CONTINUOUS AND DISCOMFORTABLE (LEVEL C) DIRTY SOCKS, MUSTY DRY SMELL. APPARENT CABIN SOURCE: UNKNOWN. FLIGHT DECK, FWD CABIN, MID CABIN, AND AFT CABIN. NO VISIBLE SMOKE/HAZE. NO MEDICAL ATTENTION REQUIRED.