Flap40, you also fell into a trap (easy to do with these figures), assuming that the difference between OWE and MZFW always represents a full passenger load (which it can, but usually doesn't). The MZFW for the A340-600 is 529,200 lbs, MTOW again is 804,000 lbs, and OWE is 390,300 lbs.
The problem here is that you need a "standard" passenger weight, and you need a "standard" range for a known fuel consumption at that range, with the "standard" passenger weight. I simply used the "standard" passenger weight given in the chart, which is 210 lbs, which I know is too low. If you use the difference between OWE and MZFW to calculate a "standard" passenger weight, that falls in the neighborhood of 350-375 lbs which is too high (assuming we're talking about a regular passenger flight with baggage and no other freight, just for comparision purposes).
How did you arrive at your figures? What range did you use to normalize to? Obviously the range of the A380 will be much shorter if it takes off with 20,000 gals less than a full fuel load.
BTW, I think I know of a better way to calculate this. I'll have to test it and include it later, when I have time.
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Safe flying to you...
[This message has been edited by Flight Safety (edited 13 April 2001).]