What was found
FLT#369, BOS-FLL. 'LEVEL 2 ODOR EVENT DESCENDING THROUGH 20000FT. STRONG ODOR PRIMARILY FRONT CABIN AND COCKPIT. DIRTY SOCK. UTILIZED ODOR ISOLATION CHECKLIST. ODOR RETURNED AFTER 5 MINUTES AND LINGERED IN FRONT AND REAR OF AIRCRAFT FOR REMAINDER OF FLIGHT APPROXIMATELY 3 MINUTES. ALL CREW NOTICED. NO PAX COMPLAINTS; APPLIED TSM 05-50-00-810-085B , COMPLIED WITH INFORMATION NOTICE 2017-T015 SECTION B`2 . IDENTIFIED ODOR COMING FROM APU BLEED SYSTEM . DECONTAMINATION LEVEL B WAS ACCOMPLISHED PER TSM 05-50-00-810-085B /05-50-00-810-085. A/C OK FOR SERVICE.'