What was found
WITH CENTER TANK FUEL REMAINING AND WITH ALL 6 FUEL PUMPS ON, RT MAIN TANK SHOWED LOSS OF 500 POUNDS IN FIRST HR OF FLIGHT. ACFT GROUNDED. ACCOMPLISHED FQIS OPS TEST, REF AMM 28-41-00. NO FAULTS IN CURRENT STATUS OR FAULT HISTORY LAST FLIGHT. FQIS GROUND TEST GOOD. TRANSFERED FUEL BETWEEN CTR & NR 2 TANKS. NO FLUCTUATIONS OF FUEL INDICATION. TRANSFERED FUEL BACK. BEFORE FUEL TRANSFER, SUMPED NR 2 TANK. NO WATER FOUND. SUSPECT WATER AT TIME OF INDICATION ISSUE. REF COMPARISON CHECK ACCOMPLISHED PREVIOUS DAY.