Narrative:

Departed airport with blowing snow and reduced visibility. We were about 30 mins late out of boston due to changing aircraft and WX conditions. Flew higher airspeed to try to make up time. We were also kept at lower altitudes by ATC. Fuel burn was higher than flight plan by about 800 pounds. At planned cruising altitude FL390, fuel burn was still higher than flight plan. We slowed from .80 mach to .78 mach. Fuel burn still higher. Also noticed 500 pounds less fuel in left wing tank than right wing tank. During the next 1.5 hours fuel imbal went to 800 pounds less in left tank. Contacted dispatch and maintenance. We looked at the fuel leak checklist. Passed maintenance our fuel burn numbers. We could not determine that a significant amount of fuel had been lost. At 1000 pounds imbal, we discussed diverting to lnk, but it was about the same flight time to continue to den. Touchdown at den with 1200 pound imbal. At the gate, a mechanic told us we had a fuel leak in the left engine. Den fire department was sent to our aircraft because of the fuel spill. We did not declare an emergency during the flight, but we were flying mostly direct and had no delays landing. We had reviewed leak checklist, driftdown, and engine failure checklist during flight.

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Original NASA ASRS Text

Title: AN A319 FLT CREW NOTICE A CHANGING FUEL IMBAL DURING FLT. ON THE GND, THERE WAS A NOTICEABLE FUEL LEAK FROM 1 ENG.

Narrative: DEPARTED ARPT WITH BLOWING SNOW AND REDUCED VISIBILITY. WE WERE ABOUT 30 MINS LATE OUT OF BOSTON DUE TO CHANGING ACFT AND WX CONDITIONS. FLEW HIGHER AIRSPD TO TRY TO MAKE UP TIME. WE WERE ALSO KEPT AT LOWER ALTS BY ATC. FUEL BURN WAS HIGHER THAN FLT PLAN BY ABOUT 800 LBS. AT PLANNED CRUISING ALT FL390, FUEL BURN WAS STILL HIGHER THAN FLT PLAN. WE SLOWED FROM .80 MACH TO .78 MACH. FUEL BURN STILL HIGHER. ALSO NOTICED 500 LBS LESS FUEL IN L WING TANK THAN R WING TANK. DURING THE NEXT 1.5 HRS FUEL IMBAL WENT TO 800 LBS LESS IN L TANK. CONTACTED DISPATCH AND MAINT. WE LOOKED AT THE FUEL LEAK CHKLIST. PASSED MAINT OUR FUEL BURN NUMBERS. WE COULD NOT DETERMINE THAT A SIGNIFICANT AMOUNT OF FUEL HAD BEEN LOST. AT 1000 LBS IMBAL, WE DISCUSSED DIVERTING TO LNK, BUT IT WAS ABOUT THE SAME FLT TIME TO CONTINUE TO DEN. TOUCHDOWN AT DEN WITH 1200 LB IMBAL. AT THE GATE, A MECH TOLD US WE HAD A FUEL LEAK IN THE L ENG. DEN FIRE DEPT WAS SENT TO OUR ACFT BECAUSE OF THE FUEL SPILL. WE DID NOT DECLARE AN EMER DURING THE FLT, BUT WE WERE FLYING MOSTLY DIRECT AND HAD NO DELAYS LNDG. WE HAD REVIEWED LEAK CHKLIST, DRIFTDOWN, AND ENG FAILURE CHKLIST DURING FLT.

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.