Narrative:

We departed on time. We were assigned a cruise altitude of FL330. The first officer was the pilot flying and I was the pilot not flying during the flight. Approximately ten minutes into the flight; we received a fuel configuration EICAS advisory message and the fuel configuration light illuminated on the fuel panel. I made a quick note of the fuel quantity totals depicted on the fuel quantity indicators on a spare sheet of paper at approximately twelve minutes into the flight (left tank fuel quantity = 12.0; center tank fuel quantity = 24.7; right tank fuel quantity = 14.3; total fuel quantity = 51.0). We checked to make certain the fuel panel was correctly configured for flight. It was. We confirmed that the APU was correctly selected to the off position. It was. Prior to departure; we had operated the aircraft per flight operations manual and pilot handbook procedures. While conducting the taxi checklist; the fuel quantity totals were correct for the flight and the fuel was correctly balanced in the respective main tanks. I next reviewed the aircraft fuel slip to double check that the fuel added to the aircraft was correctly done. It was. At this point; we were not certain of the cause of the fuel imbalance between main tanks. The engine instruments all appeared to be normal; engine fuel flow indications were matched and normal for climb power settings and everything appeared to operating within normal engine parameters. We discussed the possible causes: fuel quantity gauge error; abnormally high fuel burn with the left engine; a faulty fuel pump; and a fuel leak? We completed the fuel configuration QRH checklist. At this point in the flight; the total fuel quantity remaining matched the planned fuel remaining per the release. Fuel flow indications for both engines did not appear to be excessive - fuel flows were matched. Totalizer fuel values compared adequately to calculated fuel value quantities in the prog 2 page of the FMC. There was no change to the prog page arrival fuel indicated for our destination. However; the fuel imbalance continued to increase between the main tanks. The only thing that appeared incorrect was the individual tank quantity in the left main fuel tank. We manipulated the center tank fuel pumps in an attempt to correct or arrest the fuel imbalance with no apparent success. I next assumed the pilot flying position and the first officer assumed the pilot not flying position and he contacted dispatch and maintenance for assistance. I then notified ARTCC and advised them of our situation and the possibility that we may seek to divert. I told center that we were in contact with dispatch and we would advise them of our plans. The first officer contacted dispatch through a phone patch and communicated our situation. After consulting with both dispatch and maintenance; they advised us to divert. They both agreed that we should perform an overweight landing at the divert airport. I then contacted center and requested vectors to the diversion airport. An emergency was declared. The first officer contacted the flight attendants and advised them of our diversion and discussed the situation with them. A PA was next made to the passengers. The first officer resumed the pilot flying duties and we continued to the divert airport. I made a follow-up PA to the passengers during the descent. The overweight landing checklist was completed and an uneventful landing was conducted to the runway. Aircraft rescue and fire fighting (arff) equipment were placed alongside the runway as we landed and met us on the taxiway and inspected the aircraft. After visually inspecting the aircraft; arff found no visible evidence of any fluid or fuel leak and cleared us to taxi to the gate. Upon arrival at the gate; company maintenance technicians met us and passenger services personnel boarded the aircraft to assist the passengers with their travel needs. Landing weight was approximately 216;000 pounds upon touchdown. Appropriate fdml entries weremade and we shared our experience with the maintenance personnel. Company maintenance technicians later informed me that the probable cause was a faulty left center tank fuel pump.

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Original NASA ASRS Text

Title: A B757-200's left center tank fuel pump failed in flight causing the FUEL CONFIG light to illuminate after the left fuel tank quantity decrease two thousand pounds below the right tank. An emergency was declared and the flight diverted.

Narrative: We departed on time. We were assigned a cruise altitude of FL330. The First Officer was the pilot flying and I was the pilot not flying during the flight. Approximately ten minutes into the flight; we received a FUEL CONFIG EICAS advisory message and the FUEL CONFIG light illuminated on the fuel panel. I made a quick note of the fuel quantity totals depicted on the fuel quantity indicators on a spare sheet of paper at approximately twelve minutes into the flight (Left tank fuel quantity = 12.0; Center tank fuel quantity = 24.7; Right tank fuel quantity = 14.3; Total fuel quantity = 51.0). We checked to make certain the fuel panel was correctly configured for flight. It was. We confirmed that the APU was correctly selected to the off position. It was. Prior to departure; we had operated the aircraft per Flight Operations Manual and Pilot Handbook procedures. While conducting the Taxi Checklist; the fuel quantity totals were correct for the flight and the fuel was correctly balanced in the respective main tanks. I next reviewed the aircraft fuel slip to double check that the fuel added to the aircraft was correctly done. It was. At this point; we were not certain of the cause of the fuel imbalance between main tanks. The engine instruments all appeared to be normal; engine fuel flow indications were matched and normal for climb power settings and everything appeared to operating within normal engine parameters. We discussed the possible causes: fuel quantity gauge error; abnormally high fuel burn with the left engine; a faulty fuel pump; and a fuel leak? We completed the FUEL CONFIG QRH checklist. At this point in the flight; the total fuel quantity remaining matched the planned fuel remaining per the release. Fuel flow indications for both engines did not appear to be excessive - fuel flows were matched. Totalizer fuel values compared adequately to calculated fuel value quantities in the PROG 2 page of the FMC. There was no change to the PROG page arrival fuel indicated for our destination. However; the fuel imbalance continued to increase between the main tanks. The only thing that appeared incorrect was the individual tank quantity in the left main fuel tank. We manipulated the center tank fuel pumps in an attempt to correct or arrest the fuel imbalance with no apparent success. I next assumed the pilot flying position and the First Officer assumed the pilot not flying position and he contacted Dispatch and Maintenance for assistance. I then notified ARTCC and advised them of our situation and the possibility that we may seek to divert. I told Center that we were in contact with Dispatch and we would advise them of our plans. The First Officer contacted Dispatch through a phone patch and communicated our situation. After consulting with both Dispatch and Maintenance; they advised us to divert. They both agreed that we should perform an overweight landing at the divert airport. I then contacted Center and requested vectors to the diversion airport. An emergency was declared. The First Officer contacted the flight attendants and advised them of our diversion and discussed the situation with them. A PA was next made to the passengers. The First Officer resumed the pilot flying duties and we continued to the divert airport. I made a follow-up PA to the passengers during the descent. The Overweight Landing checklist was completed and an uneventful landing was conducted to the runway. Aircraft Rescue and Fire Fighting (ARFF) equipment were placed alongside the runway as we landed and met us on the taxiway and inspected the aircraft. After visually inspecting the aircraft; ARFF found no visible evidence of any fluid or fuel leak and cleared us to taxi to the gate. Upon arrival at the gate; company maintenance technicians met us and passenger services personnel boarded the aircraft to assist the passengers with their travel needs. Landing weight was approximately 216;000 LBS upon touchdown. Appropriate FDML entries weremade and we shared our experience with the maintenance personnel. Company maintenance technicians later informed me that the probable cause was a faulty left center tank fuel pump.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.