<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by Swiss Tony:
NM - Is there one factor you failed to take into account, that being that the plane will get lighter as it burns those 200,000 or so lbs of fuel?
(you may have included this in your efficiency ratio, not sure)</font>
I considered this when taking an average fuel burn of 20,000 lb/hour. At 800,000 lb of aircraft to keep in the sky, you will be looking at more like 23,000 lb/hour, reducing to closer to 18,000 lb/hour at an A340-500's MLW. Remember that the fuel you use in the last hour of flight has to have been carried for the previous 16 hours as "freight".
Its generally cheaper to collect more along the way than to freight it along with you.