Date registered: Jan 2009
Vehicle: 2002 CLK320; 2006 CLK350 Cabriolet; 2011 E350 Cab; 2014 E550 Cab
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It's usually more fuel-efficient flying from West to East, although there are times when you have to go out of your way to get the tailwind assist from the jet stream, and therefore you don't save quite as much.
Although I've never flown a B-747, based on my years as captain on an MD-11 (just a few hundred thousand pounds smaller, at 630,500# max takeoff gross weight, I can tell you that you're not using anywhere near 20% of your fuel, just for the takeoff. Maybe 5 or 10,000 pounds, but on a jet (MD-11) that can carry over 260,000 pounds of fuel, that's to be expected. As for fuel dumping, the most I ever had to get rid of was 55,000 pounds of fuel, while circling over Chicago, due to a precautionary engine shutdown, because of a leak in a bleed air duct. Of course the good people of Chicago never felt the effects of that fuel dump, because the stuff evaporates before it hits the ground.