HKG-LHR, GC distance of 6000nm, flying East to West so I'll use a headwind of lets say 60kts average, take-off mass of 380,000Kg, using LRC with optimum step-climbs gives me a burn of 145,000kg and just under 14 hours flight time.
I'm sure someone who flies this route often will know much more accurate figures using their Econ speeds, known average winds and actual ground distance etc but I did my calculation straight from the 744 Perf manual so hopefully its in the park.
If you had to list them, what operational reasons make the 744 a better aircraft than a 777-300ER?
As a Pax aircraft its hard to list many reasons nowadays due to extended ETOPS routes allowed on the 777 and its ability to lift almost the same numbers but burn around 30% less fuel so I'm told. Also the old advantages of not having to turn back or divert after an engine failure are becoming mute as I understand many companies SOP's these days advise their jumbo crews to divert even though the 744 is more than able to safely continue on 3 engines with no loss of capability other than a reduction in cruise level and range.
From what I understand the purchase price of second hand 777 equipment is still high so some airlines are unable to replace them for the time being but as the fuel prices and competition increase the more the 777 becomes a necessity and the more the 744 will be converted to freighters, and there is actually a very strong demand for said 744 conversions at the moment as it is fantastic in this role.