What was found
DURING CLIMBOUT YELLOW "IMBAL" ALERT APPEARED FOR NR 1 MAIN TANK. CONFIGURATION : ALL 6 BOOST PUMPS ON WITH T/O FUEL =27,000. NR 1 MAIN TANK INDICATED =800 LESS THAN NR 2 MAIN TANK. ACFT GROUNDED. ACCOMPLISHED FQIS BITES REF FIM 28-41, TASK 801, NO FAULT FOUND. ACCOMPLISHED CDS BITE REF FIM 31-62, TASK 801, NO FAULT FOUND. PERFORMED LT CENTER BOOST PUMP OPS TEST, OPS CHECK NORMAL. TRANSFER 2,000 LBS FROM LT AND RT CENTER BOOST PUMPS TO MAIN TASKS. VERIFIED THAT BOTH BOOST PUMPS, OPERATED SAME RATE. PERFORMED VISUAL INSPECTION, NO DEFECT NOTED, REF AMM 28-22-41-860-020.