Narrative:

Maintenance placarded the R1 fuel pump inoperative because the switch was bad and there was not enough time to fix it. Per the procedure in the MEL, the xfeed was to stay open for takeoff initial climb. Shortly after takeoff, I observed the fuel panel to find we had a 700 pound imbal. Shortly thereafter, we received a fuel asymmetry alert which occurs at 770 pounds. At 3000 ft I attempted to close the xfeed switch and the remaining R2 pump showed a fault leaving us only suction feed to the right engine. I opened the xfeed and noticed the R2 faulted pump came back on line. The asymmetry was now at 1400 pounds and climbing and we tried to close the xfeed again only to see the fault recurred on the R2 pump. The asymmetry was at 1600 pounds and climbing and the limitation being 2200 pounds, I declared an emergency and returned to dfw. The asymmetry upon landing was 1900 pounds and the landing weight was 82000 pounds. Maintenance, after gate arrival, discovered that the remaining R2 pump which was not placarded was in fact inoperative also. We could not have figured this out until after takeoff because the xfeed fuel was satisfying our fuel demands from the corresponding tank.

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Original NASA ASRS Text

Title: A FOKKER 100 ON TKOF AND INITIAL CLB AT 3000 FT RETURN LAND DUE TO A FUEL IMBAL NEAR MAX LIMITS CAUSED BY A R TANK BOOST PUMP PREVIOUSLY DEFERRED AS INOP AND INTERMITTENT OP OF THE REMAINING TANK PUMP. ALL FUEL WAS BURNED FROM THE L TANK.

Narrative: MAINT PLACARDED THE R1 FUEL PUMP INOP BECAUSE THE SWITCH WAS BAD AND THERE WAS NOT ENOUGH TIME TO FIX IT. PER THE PROC IN THE MEL, THE XFEED WAS TO STAY OPEN FOR TKOF INITIAL CLB. SHORTLY AFTER TKOF, I OBSERVED THE FUEL PANEL TO FIND WE HAD A 700 LB IMBAL. SHORTLY THEREAFTER, WE RECEIVED A FUEL ASYMMETRY ALERT WHICH OCCURS AT 770 LBS. AT 3000 FT I ATTEMPTED TO CLOSE THE XFEED SWITCH AND THE REMAINING R2 PUMP SHOWED A FAULT LEAVING US ONLY SUCTION FEED TO THE R ENG. I OPENED THE XFEED AND NOTICED THE R2 FAULTED PUMP CAME BACK ON LINE. THE ASYMMETRY WAS NOW AT 1400 LBS AND CLBING AND WE TRIED TO CLOSE THE XFEED AGAIN ONLY TO SEE THE FAULT RECURRED ON THE R2 PUMP. THE ASYMMETRY WAS AT 1600 LBS AND CLBING AND THE LIMITATION BEING 2200 LBS, I DECLARED AN EMER AND RETURNED TO DFW. THE ASYMMETRY UPON LNDG WAS 1900 LBS AND THE LNDG WT WAS 82000 LBS. MAINT, AFTER GATE ARR, DISCOVERED THAT THE REMAINING R2 PUMP WHICH WAS NOT PLACARDED WAS IN FACT INOP ALSO. WE COULD NOT HAVE FIGURED THIS OUT UNTIL AFTER TKOF BECAUSE THE XFEED FUEL WAS SATISFYING OUR FUEL DEMANDS FROM THE CORRESPONDING TANK.

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.