What was found
AIRCRAFT NOT GROUNDED: FUEL BURNING OUT OF WINGS PRIOR TO EXHAUSTING CENTER TANK FUEL. FUEL LOAD WAS 29K. WITH 19.8 INBOARD, LEFT WAS 8.3, RIGHT 7.5 AND CENTER STILL HAD 3.87. TURNED CENTERS OFF IN FLIGHT MOMENTARILY TO X-FEED AND AVOID WING TANKS EXCEEDING 1000K BALANCE LIMITATION. NOTE: WHEN CENTER TANKS TURNED OFF. LOW PRESSURE LIGHTS DID NOT ILLUMINATE. SUCCESSFUL X-FEED RETURNED CENTER PUMPS ON. ACCOMPLISHED GROUND FAULT INTERRUPTER OPERATIONAL TEST. ALL OPS OF CENTER FUEL PUMPS AND LOW PRESS LIGHTS FUNCTION NORMAL IAW AMM 28-22-41. ACCOMPLISHED GROUND FAULT INTERRUPTER OPERATIONAL TEST. ALL OPS OF CENTER FUEL PUMPS AND LOW PRESS LIGHTS FUNCTION NORMAL PER AMM 28-22-41.