Originally Posted by Timbo

The other advantage of the 777LR is it's range. We did the math the other night and we came up with about 20-21 hours with full fuel (330,000lbs). Of course if you're full of fuel you're not full of cargo and pax too, that's why it's usually "Load Optimized" coming out of Joburg.

Some nights it's 17 hours flying time (plus alternate fuel, etc.) and the field elevation at JNB is 5,500, which is 300 feet higher than DEN. The most fuel I've had on board is 310,000, only because it was snowing in ATL (a year ago Jan.) I've never seen them fill it all the way up with fuel. BUT I have seen the note, "Must burn fuel to get down to max T/O wt."

The 777 is a "range" airplane, whereas the 747 is an "Uplift" airplane. If you need tons of stuff, and 400 pax, moved a shorter range (12-14 hours), use the 747. If instead you have less pax, and some cargo, but it needs to go a lot further, non-stop (16-17 hrs.) use the 777.