What was found
SUSPECTED FUEL LEAK ENROUTE 2 HOURS INTO FLIGHT FUEL WAS 4000 LBS LOWER THAN EXPECTED. 15 MINUTES LATER RECEIVED FUEL QTY CHK ALERT. RAN QRH CHECKLIST & DETERMINED LEAK WAS IN UPPER AUX ESTIMATE 10000 LBS OF FUEL LEAKED.PULLED AND RESET FUEL QTY NORMAL POWER AND FUEL QTY ALTN POWER CBS & CONFIRMED FUEL QUANTITY GAUGES WERE WORKING PROPERLY. DECLARED EMERGENCY, DUMPED 47.6 OF FUEL & RTB. NO EXTERNAL LEAKS NOTED. VERIFIED FUEL WITH FUEL STICKS, OK. SUMPED ALL TANKS , NO CONTAMINATION. BITE CHECK OF FQBU IAW AMM 28-41-00-5, NO FAULTS. PERFORMED RTS OF FSC IAW AMM 28-08-01-5 NO FAULTS, TRANFERRED FUEL BETWEEN TANKS & VERFIED QTY WITH FUEL STICKS, OK. TANK QTY &TOTALIZER HAS REMAINED STABLE.