Narrative:

Normal takeoff and initial climbout; first indication of potential trouble was a 400 lb fuel imbalance as we were passing approximately 10;000 feet. I made a mental note of it and decided I would rebalance the tanks at cruise when a more accurate reading could be taken. A few minutes later; the first officer called my attention to the #1 main fuel gauge; which had just turned amber with an imbalance indication. At that point we performed the fuel imbalance checklist. The fuel quantity continued to decrease in the #1 tank; and we asked the flight attendants to see if they could observe any fuel streaming from the port side of the aircraft. They could not see any leaks. Our total fuel quantity shown on the FMC supported what we saw on the gauges; and the #1 quantity continued to decrease. At that point the QRH directed us to the fuel leak checklist. After completing it; and based on the still decreasing fuel quantity; we had to assume we were experiencing an actual fuel leak. The QRH directed us to the engine shutdown and single engine landing checklist. We declared an emergency with ATC and shutdown the #1 engine as we descended back to our departure airport. We made an uneventful single-engine landing and returned to the gate after the fire marshall confirmed no observable fuel leaking from the aircraft. Our jumpseater also ran the numbers for the flaps 15 return and advised us that there would be no brake cooling issues. After returning to the gate; we advised dispatch and debriefed the event with the chief pilot on call.

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Original NASA ASRS Text

Title: B737-700 flight crew experiences a fuel imbalance shortly after takeoff which exceeds limitations passing FL230. The engine is shut down in accordance with QRH fuel leak procedures and flight returns to departure airport.

Narrative: Normal takeoff and initial climbout; first indication of potential trouble was a 400 lb fuel imbalance as we were passing approximately 10;000 feet. I made a mental note of it and decided I would rebalance the tanks at cruise when a more accurate reading could be taken. A few minutes later; the First Officer called my attention to the #1 main fuel gauge; which had just turned amber with an imbalance indication. At that point we performed the Fuel Imbalance checklist. The fuel quantity continued to decrease in the #1 tank; and we asked the Flight Attendants to see if they could observe any fuel streaming from the port side of the aircraft. They could not see any leaks. Our total fuel quantity shown on the FMC supported what we saw on the gauges; and the #1 quantity continued to decrease. At that point the QRH directed us to the Fuel Leak checklist. After completing it; and based on the still decreasing fuel quantity; we had to assume we were experiencing an actual fuel leak. The QRH directed us to the Engine Shutdown and Single Engine Landing checklist. We declared an emergency with ATC and shutdown the #1 engine as we descended back to our departure airport. We made an uneventful single-engine landing and returned to the gate after the Fire Marshall confirmed no observable fuel leaking from the aircraft. Our jumpseater also ran the numbers for the flaps 15 return and advised us that there would be no brake cooling issues. After returning to the gate; we advised Dispatch and debriefed the event with the Chief Pilot on Call.

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.