What was found
FLT#7, JFK-LHR. (ETOPS) (AIRCRAFT PERFORMED AN AIR TURN BACK TO JFK) ' WET DIRTY SOCKS SMELL OBSERVED IN COCKPIT, FRONT GALLEY AND AFT GALLEY DURING TAXI. SMELL INTENSIFIED AND CHANGED TO A SLIGHTLY BURNING SMELL AFTER TAKEOFF. DURING DESCENT SMELL CHANGED BACK TO DIRTYU SOCKS AND INCREASED IN INTENSITY. SMELL DURING ALL PHASES OCCURRED WHILE ENGINES FOR BLEED AIR; T/S SHOT TO #1 ENG AT FAULT REF LOG PAGE 3727248-2 (REF WO 1278279 FOR ALL WORK ACCOMPLISHED & INSPECTION ITEMS FOR REMOVAL AND REPLACEMENT OF #1 ENG) FOR REPLACEMENT. PERFORMED ECS DECONTAMINATION PER AMM 21-00-00-615-802-A OPERATED PACKS USING ENGINE/ APU BLEED NO ORDOR PRESENT.