A B737 IS SHORTED 3000 LBS OF FUEL AT DFW AND LANDS WITH 4000 LBS OF FUEL REMAINING AT ABQ. THE R WING FUEL GAUGE WAS READING 3000 LBS HIGH ON THE REFUELING BUT INDICATED A SLOW DECREASE SIMILAR TO A FUEL IMBALANCE SIT ENRTE.

Narrative

ENRTE FROM DAL TO ABQ; THE CAPT AND I OBSERVED THE R WING TANK FUEL DECREASING AT AN ABNORMALLY HIGH RATE. WE MADE A TURN TO SEE IF WE COULD DETECT A FUEL VAPOR TRAIL; BUT SAW NOTHING. WE ALSO HAD A FLT ATTENDANT LOOK AT THE R WING AND ENG AREA FROM THE CABIN TO SEE IF FUEL WAS LEAKING; BUT SHE OBSERVED NOTHING ABNORMAL. WE OBSERVED THE ACFT TRIM FOR AN INDICATION THAT THE L WING WAS BECOMING HEAVIER THAN THE R (THE 1500 LB IMBALANCE WE WERE OBSERVING WOULD NORMALLY CAUSE A LARGE YOKE DISPLACEMENT AWAY FROM THE HVY SIDE); BUT SAW NOTHING ABNORMAL. AS A RESULT; WE CONCLUDED THE PROB WAS NOT A LEAK BUT MOST LIKELY A FAILURE IN THE R FUEL GAUGE SYS. WE CHKED FOR POPPED CIRCUIT BREAKERS BUT FOUND NONE. TO BE ON THE SAFE SIDE; WE REVIEWED LOW FUEL OPS IN THE QUICK REACTION CHKLIST FOR ANY HELPFUL INFO. ALTHOUGH WE DISCUSSED DIVERTING INTO LBB OR MAF; WE DECIDED WE COULD CONTINUE ON TO ABQ; SINCE EVEN IN THE UNLIKELY EVENT THAT IT WAS A FUEL LEAK AND WE LOST ALL THE FUEL OUT OF THE R WING TANK; WE WOULD STILL LAND AT ABQ WITH 4000 LBS OF FUEL; WHICH WAS ABOVE MINIMUM FUEL. WX WAS NOT A FACTOR ANYWHERE WE CONSIDERED GOING; AND ABQ HAD 3 RWYS; TWO OF WHICH DIDN'T INTERSECT. WE NOTIFIED OUR DISPATCH THAT WE WOULD NEED CONTRACT MAINT WHEN WE REACHED ABQ. DURING OUR DSCNT INTO ABQ; ONE OF THE TWO R BOOST PUMP LOW PRESSURE LIGHTS ILLUMINATED. THIS WAS AN INDICATION OF LOW FUEL QUANTITY IN THE R WING TANK. WE IMMEDIATELY EXECUTED THE LOW FUEL CHKLIST; WHICH CALLS FOR; IN PART; OPENING THE XFEED VALVE BTWN THE L AND R TANKS. (WE HAD NOT DONE THIS BEFORE BECAUSE WE BELIEVED WE HAD A GAUGE PROB; NOT AN ACTUAL FUEL LOSS PROB; AND TURNING ON THE XFEED IN SUCH A SIT COULD HAVE CAUSED A LARGE IMBALANCE TO OCCUR WHICH WE WOULD NOT HAVE BEEN ABLE TO MONITOR.) TURNING ON THE XFEED RESTORED PRESSURE TO ALL PUMPS AND WE LANDED NORMALLY IN ABQ WITH ABOUT 200 LBS SHOWING IN THE R TANK AND 4000 LBS TOTAL FUEL ONBOARD. AFTER SHUTDOWN AT THE GATE; WE HAD THE FUELER CHK THE R TANK QUANTITY BY DRIP STICK; AND HE FOUND THAT THERE WAS NO FUEL IN THE TANK. (THE DRIP STICK WILL NOT SHOW ANY FUEL WITH LESS THAN 700 LBS REMAINING). INVESTIGATION BY MAINT FOUND THAT THE R GAUGE WAS INDEED MALFUNCTIONING AND WAS INDICATING 3000 LBS HIGH AT HIGHER FUEL QUANTITIES. CONSEQUENTLY; WHEN THE ACFT WAS SVCED BEFORE FLT; THE R TANK HAD ABOUT 3000 LBS LESS FUEL THAN THE L; ALTHOUGH BOTH FUEL GAUGES READ THE SAME. BY COINCIDENCE; THE ACFT RIG WAS SUCH THAT IT WAS CONSIDERABLY R WING HVY; WHICH WAS COUNTERBALANCED BY THE MISSING FUEL SUCH THAT WE DETECTED ONLY MINIMAL TRIM REQUIREMENTS ON TKOF WITH THE LARGE FUEL IMBALANCE. DUE TO THE DESIGN OF THE FUEL INDICATION SYS; THE SYS BEGAN CORRECTING FOR THE ERROR DURING THE FLT; SO THAT THE GAUGE CORRECTLY READ 200 LBS WHEN THE SYS ACTUALLY HAD 200 LBS REMAINING. IN THE COCKPIT; THIS APPEARED AS A RAPIDLY DECREASING FUEL QUANTITY IN THE R SYS; WHILE IN FACT WE HAD A CONSTANT 3000 LB DIFFERENCE BTWN THE 2 TANKS. THE CONSTANT 3000 LB DIFFERENCE THROUGHOUT THE FLT WAS ALSO THE REASON WE NEVER SAW A TRIM CHANGE AS THE R TANK APPEARED TO EMPTY. OUR COMPANY IS STILL IN THE PROCESS OF INVESTIGATING HOW THIS SIT OCCURRED AND HOW IT CAN BE PREVENTED IN THE FUTURE. MY LESSON FROM THIS IS REINFORCEMENT THAT ANY FUEL SIT IS POTENTIALLY DANGEROUS; NO MATTER HOW BENIGN IT MAY APPEAR. ALWAYS TAKE THE MOST CONSERVATIVE COURSE OF ACTION WHEN DEALING WITH FUEL PROBS; AND ENSURE THAT FUEL WILL BE SUFFICIENT FOR THE COURSE OF ACTION CHOSEN; EVEN UNDER A WORSE CASE SCENARIO. AS I HEARD FROM MY FLT INSTRUCTOR MANY YRS AGO; ONE OF THE THINGS OF LITTLE USE TO A PLT IN THE AIR IS 'FUEL IN THE FUEL TRUCK.' CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: FO RPTR INDICATED THAT THE AIRLINE MAINT POLICY/PROC DOES NOT INCLUDE ANY REF TO FUEL ADDED FOR THE FLC'S INFO. THE FUELING SLIP IS SENT DIRECTLY TO THEIR OPS AGENT AT THE GATE AND THE CREW SIMPLY COMPARES THE GAUGE READING WITH THE FUEL REQUIRED ON THE DISPATCH RELEASE PAPERS. WHEN THE FO HAD LAST SPOKEN WITH HIS CHIEF PLT ABOUT THIS INCIDENT THE CHIEF PLT STATED THAT AS FAR AS HE KNEW THE FUEL GAUGE HAD BEEN A REPLACEMENT PRIOR TO THIS FLT AND HE THOUGHT THAT THE INST HAD NOT BEEN CALIBRATED PROPERLY. NO FURTHER INFO WAS MADE AVAILABLE TO THE FO. RPTR WAS COUNSELED TO INQUIRE IF THE ACR WAS GOING TO CHANGE THEIR FUEL SLIP FORM AND HANDLING METHODS.