DIVERT ACCOUNT FUEL PROB.

Narrative

DEPARTED ORLANDO WITH 21000 LBS OF FUEL ACCORDING TO GAUGES (1000 LBS IN CTR TANK AND 10000 LBS IN EACH MAIN TANK). NO OTHER MEANS TO CHK FUEL QUANTITY ANYMORE AS WE NO LONGER RECEIVE FUEL SLIPS. FLT WAS THEN NORMAL UNTIL IN THE VICINITY OF RDU. THE CAPT NOTICED THE 'INSUFFICIENT FUEL' LIGHT ON THE FMC. WE THEN SAW THE FUEL GAUGES INDICATING 5800 LBS IN THE L TANK AND '0' LBS IN THE R AND CTR TANKS. ALL FUEL BOOST PUMPS WERE TURNED ON AND XFEED OPENED AND IGNITION TURNED ON. SUSPECTING GAUGE FAILURE; CIRCUIT BREAKERS WERE RESET AND FUEL GAUGES TESTED TO NO AVAIL. A DSCNT WAS BEGUN WITH PRECAUTIONARY LNDG CONSIDERED. FUEL GAUGE FAILURE PROC EXAMINED. SIT REMAINED THE SAME; SO CAPT DECIDED THAT SINCE WE HAD NO IDEA WHETHER THE GAUGE FAILED OR THAT WE ONLY HAD 5800 LBS OF FUEL ON BOARD; A PRECAUTIONARY LNDG AT RDU SHOULD BE MADE. AFTER LNDG AND CHKING FUEL WITH DRIPSTICKS; IT WAS FOUND WE INDEED HAD THE FUEL -- APPROX 5600 LBS IN L TANK AND 8300 LBS IN R TANK. REASON FOR GAUGE FAILURE UNKNOWN; SO ACFT WAS SVCED WITH A KNOWN QUANTITY OF FUEL; GAUGE WAS PUT ON MEL; AND FLT CONTINUED ON. REASON FOR IMBAL UNKNOWN ALSO; BUT COULD HAVE BEEN DURING FUELING; EARLIER BALANCING; XFEEDING IN DSCNT; OR CTR TANK NOT FEEDING PROPORTIONATELY; OR ANY COMBINATION OF THESE -- NONE OF WHICH COULD BE DONE CORRECTLY OR NOTICED IF THE GAUGE WAS INCORRECT OR ON '0.' SUGGEST PLTS HAVE BACKUP TO FUEL GAUGES (SUCH AS FUEL SLIPS) TO CHK FUEL LOADS. SEEMS THAT SINCE FUEL IS SO IMPORTANT; IT SHOULD NOT BE A WEAK LINK IN THE SYS. SUPPLEMENTAL INFORMATION FROM ACN 258364: TOTAL BLOCK TIME MCO-RDU WAS 1:31. THAT COMPUTES TO APPROX 8000 LBS BURNOFF. RDU MAINT DRIPPED THE TANKS AND FOUND APPROX 14000 LBS ON BOARD. 21600 LBS - 8000 LBS = 13600 LBS. THEY FOUND THE FUEL GAUGE IN THE REFUELING PANEL TO BE INOP AND THE REFUELING VALVES IN THE OPEN POS. RDU MAINT DETERMINED THE R FUEL GAUGE WAS INOP. IT WAS MEL'ED AND I WAS DISPATCHED TO BDL USING FUEL GAUGE INOP PROCS.