CAPT OF A B777 RPTS LARGE DISCREPANCIES BETWEEN PLANNED VERSUS ACTUAL ZERO FUEL WT WHICH RESULT IN DIFFICULTIES IN ACCURATELY PLANNING FUEL FOR BEST BALANCE BETWEEN SCHEDULE INTEGRITY AND FUEL EFFICIENCY.

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I CONTINUE TO HAVE PROBS IN FLT PLANNING DUE TO INACCURATE ZERO FUEL WT FURNISHED TO ME. AT THE TIME OF FLT PLANNING; THE FLT PLAN SHOWS A ZERO FUEL WT. DEPENDING ON THE CIRCUMSTANCES; I ACCEPT THE FUEL LOAD OR ADD FUEL AS NECESSARY BASED ON THAT ZERO FUEL WT. SWINGS OF 7 TO 8 THOUSAND LBS ZERO FUEL WT BETWEEN PLANNING AND DEP ARE NOT UNUSUAL. BECAUSE OF FLT PLANNING LIMITATIONS FLYING INTO JFK; I CAN PLAN ON BURNING 2 TO 4 THOUSAND MORE LBS THAN ON THE FLT PLAN. CONSEQUENTLY; I OFTEN ADD FUEL. WHEN THE ZERO FUEL WT DROPS 8 THOUSAND; THIS ADDITIONAL FUEL IS UNNECESSARY. QUITE FRANKLY; IT IS EMBARRASSING TO ARR WITH 25000 LBS OF FUEL IN VFR WX. IF THE ZERO FUEL WT RISES 8 THOUSAND AND I AND DISPATCH ARE NOT NOTIFIED; I WILL HAVE TO STOP FOR REFUELING AND MAY SUFFER FAA DISCIPLINARY ACTION FOR INADEQUATE PREFLT PLANNING. SOME MORE REAL TIME COMMUNICATION MUST TAKE PLACE IF YOU WANT TO SAVE FUEL. ACCORDING TO FUEL SCHOOL; DIVERTING IS NOT A FAILURE. I CONSIDER DIVERTING A FAILURE TO MY PAX. I THINK CENTRALIZED LOAD PLANNING IS A GOOD IDEA; BUT MORE COMMUNICATION IS NECESSARY. I HAVE TO ADD FUEL UNTIL CENTRAL LOAD PLANNING CAN RELIABLY FURNISH ME WITH AN ACCURATE PREDICTED ZERO FUEL WT.