Narrative:

During ground time between flights; I noticed that fueling had begun but then stopped as there was a larger fuel imbalance in the number one tank than the amount in the tank when we landed. Later I noted that the fueling was complete and the fuel gauges read the required amount from the dispatch release. Stopping/starting refueling operations is something I have seen on the line on numerous occasions. We successfully completed all our normal procedures including a loadsheet review and fuel audit. We taxied and took off with no issues. Shortly after takeoff; I noticed that the number one fuel gauge was suddenly reading approximately three to four thousand pounds less than it read on the ground. Initially; I thought this was some anomaly. On the older model 737 aircraft; it is common to have temporary erratic indications. After a minute or so; the gauge had not corrected. I looked over at the first officer's yoke and he was flying in a left wing down condition. I asked him if he noticed any control problems and he stated that he felt a rolling motion in the right wing down direction. This indicated to me that we might actually have a fuel imbalance. With the possibility that we had a significant fuel imbalance; gauge error; and possibly not enough fuel to get to destination (if the gauges were correct); we elected to return to [departure airport]. I informed ATC; operations; the flight attendants and the passengers. We immediately started crossfeed operations and ran the off schedule descent QRH checklist. (We received the off schedule descent light when we started back down into ZZZ). We requested maintenance and fuelers meet us at the gate. The arrival; approach; and landing went normally. We landed with a 2;500 pound fuel imbalance showing on the gauges. Back at the gate; we immediately dipsticked the tanks and confirmed that the gauge readings were correct. We landed with a 2;500 pound imbalance and had more than 3;000 pound imbalance in flight. Somehow; the number one fuel gauge had read the proper fuel balance before pushback and then self-corrected to the true amount later (we did not have engines running long enough to develop an imbalance that large and there was no evidence of a fuel leak).

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Original NASA ASRS Text

Title: B737 flight crew reported a significant fuel tank imbalance after takeoff and right roll tendency. They returned to base where fuel imbalance was confirmed. An improper fuel audit and initially inaccurate fuel gauge were cited as causes.

Narrative: During ground time between flights; I noticed that fueling had begun but then stopped as there was a larger fuel imbalance in the number one tank than the amount in the tank when we landed. Later I noted that the fueling was complete and the fuel gauges read the required amount from the Dispatch Release. Stopping/starting refueling operations is something I have seen on the line on numerous occasions. We successfully completed all our normal procedures including a loadsheet review and fuel audit. We taxied and took off with no issues. Shortly after takeoff; I noticed that the Number One fuel gauge was suddenly reading approximately three to four thousand pounds less than it read on the ground. Initially; I thought this was some anomaly. On the older model 737 aircraft; it is common to have temporary erratic indications. After a minute or so; the gauge had not corrected. I looked over at the F/O's yoke and he was flying in a left wing down condition. I asked him if he noticed any control problems and he stated that he felt a rolling motion in the right wing down direction. This indicated to me that we might actually have a fuel imbalance. With the possibility that we had a significant fuel imbalance; gauge error; and possibly not enough fuel to get to destination (if the gauges were correct); we elected to return to [departure airport]. I informed ATC; Operations; the Flight Attendants and the Passengers. We immediately started crossfeed operations and ran the Off Schedule Descent QRH Checklist. (We received the Off Schedule Descent light when we started back down into ZZZ). We requested Maintenance and Fuelers meet us at the gate. The arrival; approach; and landing went normally. We landed with a 2;500 pound fuel imbalance showing on the gauges. Back at the gate; we immediately dipsticked the tanks and confirmed that the gauge readings were correct. We landed with a 2;500 pound imbalance and had more than 3;000 pound imbalance in flight. Somehow; the number one fuel gauge had read the proper fuel balance before pushback and then self-corrected to the true amount later (We did not have engines running long enough to develop an imbalance that large and there was no evidence of a fuel leak).

Data retrieved from NASA's ASRS site 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.