What was found
AFTER T/O DURING CLIMB CREW REPORT ELECT SMELL IN CABIN NEAR AREA OF E/E COMP. SMELL DID DISAPATE AFTER LEVEL OFF. RETURNED TO LHR FOR INVESTIGATION. PERFORMED NUMEROUS AMM CHECKS AND INSPECTIONS. ALL RECORDED IN THE LOGBOOK. RECIRC/GALLEY/GASPER FANS. ALL CABIN LIGHTING/IFE/GALLEY EQUIP. CHECK DOOR ENTRY HEATERS - E/E EQUIP - EQUIP COOLING SYSTEM. PERFORMED ENG RUN BOTH ENG/PACKS ON/OFF PLACED A/C IN AIR MODE. ALL NEGATIVE RESULTS. ETOPS CATEGORY 'B': DIVERSION OR TURNBACK