Narrative:

Company aircraft had an MEL pertaining to an inoperative fuel gauge for the #1 fuel tank. Aircraft flew from mci-msp, msp-mdw, mdw-msp. On the fourth leg of day flight from msp to mdw, fuel load was planned to be approximately 22500 pounds. The fueler brought up fuel slip showing uplift of 994 gallons and with full wing tanks and approximately 3000 pounds in center tank. This calculated out to be approximately 23000 pounds of fuel. I had made a comment to expediter that the fueler would probably fill wings to the automatic shutoff and put balance in center tank. She relayed this information to the fueler as 'captain said to fill the wings and put the balance in center tank.' he did so. I'm not sure of the method he used to put a known quantity into the #1 tank with inoperative fuel gauge. I'm also not sure if he used the meter on truck to gauge the uplift to the left tank or if he xferred a known quantity from other tanks to the #1 tank. Aircraft had been sitting at gate for 90 mins. I did ask him if the left tank (#1) was full and he responded 'yes.' we departed runway 29L and during the initial climb out and cruise I noticed holding approximately 20 degrees control wheel to the left. The aircraft had flown perfectly well all day. I checked all trim wheels for proper settings and verified all slats and flaps were properly retracted. After further thought, I decided to return to msp. Made normal visual approach and landing to runway 29L. We entered in the aircraft logbook the out of trim problem. Mechanics used dripsticks to check fuel load in each wing. 6600 pounds was estimated in the #1 tank and 9600 pounds was estimated to be in #2 tank -- a 3000 pound imbalance using this dripstick method. This 3000 pound imbalance was probably the cause of the aircraft needing left aileron to fly level. Incidentally, the fuel burn to mdw is approximately 6000- 6500 pounds. The WX at mdw was VFR, so there was adequate fuel for the trip segment. Although there was fuel planned for the flight to mdw and msp was the alternate, plus extra fuel for contingencies, holding, etc. There was never any doubt about having sufficient fuel for the trip. The problem could have been avoided if company would have fixed the fuel gauge problem and not deferred it to the MEL. Also a more defined definition as to what constitutes a known quantity as well as all approved methods to obtain a known quantity, likewise, a procedure in which a certified fueler confirms in writing that the approved fueling procedure for our company's MEL and company procedures have been complied with.

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Original NASA ASRS Text

Title: B737 IS MISFUELED DURING RAMP OP GND REFUELING PROC. FUEL IMBALANCE CREATES NEED FOR RETURN LAND AT MSP.

Narrative: COMPANY ACFT HAD AN MEL PERTAINING TO AN INOP FUEL GAUGE FOR THE #1 FUEL TANK. ACFT FLEW FROM MCI-MSP, MSP-MDW, MDW-MSP. ON THE FOURTH LEG OF DAY FLT FROM MSP TO MDW, FUEL LOAD WAS PLANNED TO BE APPROX 22500 LBS. THE FUELER BROUGHT UP FUEL SLIP SHOWING UPLIFT OF 994 GALLONS AND WITH FULL WING TANKS AND APPROX 3000 LBS IN CTR TANK. THIS CALCULATED OUT TO BE APPROX 23000 LBS OF FUEL. I HAD MADE A COMMENT TO EXPEDITER THAT THE FUELER WOULD PROBABLY FILL WINGS TO THE AUTOMATIC SHUTOFF AND PUT BAL IN CTR TANK. SHE RELAYED THIS INFO TO THE FUELER AS 'CAPT SAID TO FILL THE WINGS AND PUT THE BAL IN CTR TANK.' HE DID SO. I'M NOT SURE OF THE METHOD HE USED TO PUT A KNOWN QUANTITY INTO THE #1 TANK WITH INOP FUEL GAUGE. I'M ALSO NOT SURE IF HE USED THE METER ON TRUCK TO GAUGE THE UPLIFT TO THE L TANK OR IF HE XFERRED A KNOWN QUANTITY FROM OTHER TANKS TO THE #1 TANK. ACFT HAD BEEN SITTING AT GATE FOR 90 MINS. I DID ASK HIM IF THE L TANK (#1) WAS FULL AND HE RESPONDED 'YES.' WE DEPARTED RWY 29L AND DURING THE INITIAL CLBOUT AND CRUISE I NOTICED HOLDING APPROX 20 DEGS CTL WHEEL TO THE L. THE ACFT HAD FLOWN PERFECTLY WELL ALL DAY. I CHKED ALL TRIM WHEELS FOR PROPER SETTINGS AND VERIFIED ALL SLATS AND FLAPS WERE PROPERLY RETRACTED. AFTER FURTHER THOUGHT, I DECIDED TO RETURN TO MSP. MADE NORMAL VISUAL APCH AND LNDG TO RWY 29L. WE ENTERED IN THE ACFT LOGBOOK THE OUT OF TRIM PROB. MECHS USED DRIPSTICKS TO CHK FUEL LOAD IN EACH WING. 6600 LBS WAS ESTIMATED IN THE #1 TANK AND 9600 LBS WAS ESTIMATED TO BE IN #2 TANK -- A 3000 LB IMBALANCE USING THIS DRIPSTICK METHOD. THIS 3000 LB IMBALANCE WAS PROBABLY THE CAUSE OF THE ACFT NEEDING L AILERON TO FLY LEVEL. INCIDENTALLY, THE FUEL BURN TO MDW IS APPROX 6000- 6500 LBS. THE WX AT MDW WAS VFR, SO THERE WAS ADEQUATE FUEL FOR THE TRIP SEGMENT. ALTHOUGH THERE WAS FUEL PLANNED FOR THE FLT TO MDW AND MSP WAS THE ALTERNATE, PLUS EXTRA FUEL FOR CONTINGENCIES, HOLDING, ETC. THERE WAS NEVER ANY DOUBT ABOUT HAVING SUFFICIENT FUEL FOR THE TRIP. THE PROB COULD HAVE BEEN AVOIDED IF COMPANY WOULD HAVE FIXED THE FUEL GAUGE PROB AND NOT DEFERRED IT TO THE MEL. ALSO A MORE DEFINED DEFINITION AS TO WHAT CONSTITUTES A KNOWN QUANTITY AS WELL AS ALL APPROVED METHODS TO OBTAIN A KNOWN QUANTITY, LIKEWISE, A PROC IN WHICH A CERTIFIED FUELER CONFIRMS IN WRITING THAT THE APPROVED FUELING PROC FOR OUR COMPANY'S MEL AND COMPANY PROCS HAVE BEEN COMPLIED WITH.

Data retrieved from NASA's ASRS site as of July 2007 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.