B737-800
Flight Crew Air Transport Pilot (ATP)
Situational Awareness
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Fuel Issue
Flight Crew Became Reoriented; Flight Crew Overcame Equipment Problem
Aircraft; Human Factors
We exceeded an aircraft fuel limitation. The max imbalance of the two main tanks is 1000 pounds. We exceeded the 1000 pounds. The 737 has 2 pumps in each of the 3 tanks. We had a MEL item where the one of the pumps in the left main tank was inop. On climb out we got a light telling us that the two main wing tanks were out of balance. We pulled out the checklist and went to the procedure to correct the situation. While working on this we discovered that the center tank also had a pump that had failed. So we now had 2 fuel pumps that were inop. We ran the checklist for an inoperative fuel pump in addition to the IMBAL fuel checklist. We were able to get the two main tanks back to within the limitation and ultimately we were able to balance the fuel completely.To avoid this in the future we need to pay better attention to the fuel balance. Especially when there is an inoperative fuel pump. It happened on climb out so knowing that it can happen kind of quick is good to keep in mind.
B737-800 pilot reported exceeding maximum fuel imbalance limit when they were dispatched with a boost pump inoperative and a second boost pump failed during climb out.