B747-400 ENRTE TO SYD DIVERTS TO BRISBANE ACCOUNT INSUFFICIENT FUEL.

Narrative

A B747-400 IN CRUISE ON A579 ON A RE-DISPATCH FLT PLAN TO SYD (VIA VIRAR-NAN WITH RE-DISPATCH TO SYD) WAS RUNNING 6 MINS BEHIND FLT PLAN TIME AND 9500 LBS BELOW FLT PLAN ESTIMATED FUEL AT THE RE-DISPATCH POINT -- VIRAR. FLT WAS 3900 LBS BELOW MINIMUM RE-DISPATCH AT THE RE-DISPATCH POINT; AND WITH AN ESTIMATED 9000 LBS REMAINING AT SYD; DIVERTED TO BNE AND LNDG WITH 20.9. FLT REFUELED AND CONTINUED TO SYD ARRIVING ABOUT 2 HRS LATE. CLRED FUEL AT SFO WAS 372.2 AND BOARDED FUEL WAS 51918 GALLONS -- 355.6 LBS. ADDED TO THE 19.6 ABOARD WE HAD 375.2 -- TANK QUANTITY GAUGES INDICATED 375.7. TKOF FUEL WAS 373.0. FLT WAS 1 MIN AHEAD OF FLT PLAN AND 300 LBS UP AT FIRST CHKPOINT; LEVEL AT FL280. FUEL REMAINED STABLE AT ABOUT FLT PLAN ESTIMATED VALUE UNTIL CTR TANK BURNOUT; THEN INDICATED QUANTITY BEGAN TO DROP -- 5000 LBS IN NEXT 2 HRS. CALCULATED QUANTITY PER FUEL BURN STAYED WITH FLT PLAN. TANK VERSUS BURN SCORE BEGAN TO WIDEN AND BY VIRAR; EXCEEDED -6.0 LBS AND WAS CONTINUING TO INCREASE SLOWLY; WITH THE TANK TOTAL BEING THE LOW QUANTITY. ZERO FUEL WT WAS 400 LBS LESS THAN FLT PLAN VALUE; BUT EVEN WITH A SCORE OF -9.5 AT THE RE-DISPATCH POINT; THE FLT WAS UNABLE TO STABILIZE THE DECREASING FUEL AS INDICATED BY THE QUANTITY GAUGES; AND THE FUEL SCORE WAS APCHING 10000 LBS AND DECREASING ABOUT 500 LBS EVERY 30 MINS BELOW THE FLT PLAN ESTIMATED VALUE. THE ACFT FLEW WELL; IN TRIM WITH NO APPRECIABLE HIGH EPR AND ON MACH/ALT WITH A CI 50 SELECTION; DIDN'T STRUGGLE TO ALTER OR VARY THE CRUISE MACH MUCH AS WOULD HAPPEN WITH AN OVERWT ACFT. JUST THE GRADUAL; UNRELENTING DROP IN THE TANK QUANTITY FUEL SCORE AND THE INABILITY TO ARREST THE INCREASING DIFFERENCE IN THE BURN VERSUS QUANTITY GAUGE TOTAL NECESSITATED A DIVERSION BEFORE ARR FUEL BECAME PROBLEMATIC.