Narrative:

I was the captain and PF for flight abc lga-msp and had a planned fuel on arrival of 6500 pounds. We received release #2 for a heavier weight so the new fuel on arrival was 6200 pounds. We closely monitored the fuel while slowly getting behind. We estimated that our arrival fuel would be 5000 pounds. While passing eau VOR, I saw the fuel was at 5100 pounds and the right main tank was decreasing steadily, but rapidly. I determined it was an uncontrolled fuel leak and began a diversion to eau immediately while declaring an emergency and requested the equipment. I had the first officer fly and I called dispatch to relay my intention. While consulting the company operations manual and maintenance controller during the descent, the fuel gauge stopped decreasing and began to increase to the proper amount. I then asked the first officer to make a PA and go to the cabin to inspect the wing for a fuel leak. He reported everything normal. Dispatch or planning called ATC and they reported msp could take us straight in to msp with no holding. With the concurrence of dispatch, first officer, maintenance controller, company operations manual and the fuel gauge now reading normal, and ATC taking us straight to msp, I elected to proceed to msp and advised ATC of our intentions.

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Original NASA ASRS Text

Title: A DC9-50 IN CRUISE AT FL350 DECLARED AN EMER DUE TO R WING FUEL QUANTITY DECREASING ABNORMALLY. CAUSED BY A MALFUNCTIONING FUEL QUANTITY INDICATION SYS.

Narrative: I WAS THE CAPT AND PF FOR FLT ABC LGA-MSP AND HAD A PLANNED FUEL ON ARR OF 6500 LBS. WE RECEIVED RELEASE #2 FOR A HEAVIER WT SO THE NEW FUEL ON ARR WAS 6200 LBS. WE CLOSELY MONITORED THE FUEL WHILE SLOWLY GETTING BEHIND. WE ESTIMATED THAT OUR ARR FUEL WOULD BE 5000 LBS. WHILE PASSING EAU VOR, I SAW THE FUEL WAS AT 5100 LBS AND THE R MAIN TANK WAS DECREASING STEADILY, BUT RAPIDLY. I DETERMINED IT WAS AN UNCTLED FUEL LEAK AND BEGAN A DIVERSION TO EAU IMMEDIATELY WHILE DECLARING AN EMER AND REQUESTED THE EQUIP. I HAD THE FO FLY AND I CALLED DISPATCH TO RELAY MY INTENTION. WHILE CONSULTING THE COMPANY OPS MANUAL AND MAINT CTLR DURING THE DSCNT, THE FUEL GAUGE STOPPED DECREASING AND BEGAN TO INCREASE TO THE PROPER AMOUNT. I THEN ASKED THE FO TO MAKE A PA AND GO TO THE CABIN TO INSPECT THE WING FOR A FUEL LEAK. HE RPTED EVERYTHING NORMAL. DISPATCH OR PLANNING CALLED ATC AND THEY RPTED MSP COULD TAKE US STRAIGHT IN TO MSP WITH NO HOLDING. WITH THE CONCURRENCE OF DISPATCH, FO, MAINT CTLR, COMPANY OPS MANUAL AND THE FUEL GAUGE NOW READING NORMAL, AND ATC TAKING US STRAIGHT TO MSP, I ELECTED TO PROCEED TO MSP AND ADVISED ATC OF OUR INTENTIONS.

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.