What was found
FLT 1471 LGA-FLL. STRONG PERSISTENT FUMES FROM 12,000 UNTIL LANDING. DIRTY SOCK SMELL. ATTEMPTED TO ISOLATE PACK 1 WAS UNSUCCESSFUL. SMELLED BY BOTH PILOTS. FA'S DID NOT SMELL IN THE CABIN. LEVEL II FUME EVENT; COMPLIED WITH INFO/ NOTICE 2017-T015. IDENTIFIED SOURCE AMBIENT AIR TYPE 10. INSP APU, WHEEL WELLS, LOWER FUSELAGE, TAIL SECTION. ALL FOUND IN CLAEN CONDITION. COMPLIED WITH LVL A ECS DECON. CABIN AIR QUALITY GOOD.