What was found
SUP - ETOPS SIGNIFICANT SYSTEM - AT 4000 FT ON BASE LEG FOR 8L, DIRTY SOCK SMELL FILLED IN COCKPIT AND FIRST CLASS GALLEY, SMELL DISSIPATED ONCE ENGINES WERE SHUT DOWN. LT PACK FLOW CONTROL VALVE INOP FOR ODOR SMELL, (PACK FLOW CONTROL VALVES (AIRCRAFT WITH MOD 30626 / MP K6443). LT PACK COMPONENTS CLEANED AND ECS DECONTAMINATION ACCOMPLISHED. VERIFICATION FLIGHT INCOMPLETE. REMOVED AND REPLACED #1 ENGINE. VERIFICATION FLIGHT FOR #1 ENGINE CHANGE, VERIFICATION FLIGHT OF #1 ENGINE ACCOMPLISHED. NO DEFECTS NOTED. OK FOR SERVICE.