Ignoring whether or not passengers will actually want to fly LHR-SYD non-stop, lets look at some of the numbers involved.

For the A340-500:

MGTOW = 804,700 lb (Max Gross TakeOff Weight)
MLW = 520,300lb (Max Landing Weight)
EW = 375,700 (typical Empty Weight - no fuel, pax or cargo)
Fuel Capacity = 214,810 litres or 378,750 lb assuming Jet A1 has a specific gravity of 0.8 under normal conditions.

This gives a spread of 284,400 lb between MGTOW and MLW that is available for fuel burn during the flight without impacting lift capacity. Any time the fuel burn exceeds this spread, the flight is payload restricted. But we know the A340-500 can hold 378,700 lb of fuel, so it is possible (and indeed common) to operate in the payload restricted part of the numbers.

Fuel burn in modern commercial airliners is very much dependent on the weight of teh aircraft rather than the particular engines or aircraft type. So we can assume an average fuel burn rate of about 23,000 lb/hour when operating at MGTOW, dropping to about 18,000 lb/hour at MLW, giving an average for the flight of approx 20,000 lb/hour.

So from the max fuel burn without payload restriction (284,400 lb of fuel as determined above), we can see that a flight of more than about 14 hours is going to be payload restricted. But how much?

We also know we can squeeze up to 378,750 lb of fuel into the tanks, giving us almost 19 hours of flying time until the wick dries up. And we must keep planned flying time to maintain sufficient fuel reserves (normally 30 to 60 mins plus 2% contingency, generally resulting in approx 22,000 lb reserves), we are looking at more like 17.8 hours of actual flying time.

Also note in that case if we takeoff at MGTOW, we will be landing at about 426,000 lb. Given an EW of 375,700, this means we have been able to carry a max of 50,300 lb of pax, baggage, catering, amenities and duty-free shopping.

So how much does each passenger and their associated baggage, amenities, catering etc weight for a 19 hour flight? My best guess would be an average of say 300 lb (180 lb for pax, 80 lb baggage, 25 lb catering, 15 lb carry-on). This would mean we can carry a max of 167 passengers over the max range of the aircraft.

Now, how far can an A340-500 travel in 17.8 hours? It has a max airspeed (Mmo) of Mach 0.86. So assuming best fuel efficiency is at 90% of that, we can expect to travel at about 0.77 Mach or about 550 miles/hour. So 17.8 hours will get us 9790 miles.

While 9790 miles is enough for SIN-EWR, its not enough for LHR-SYD. As others have stated, Great Circle distance LHR-SYD is 10,573 miles, and it is possible to fly a route that is very close to the great circle track on this route.

LHR-PER is certainly inside the range window of the A340-500. However, the question that remains is about the viability of operating the route given that QF currently hub PER-LHR traffic through SIN, combining the loads for Asia and Europe onto two daily flights, one being a 763 and the other varies between 763 and 744. No First Class is offered, just Y and J.

Edited to fix silly typos

[This message has been edited by NM (edited Jan 26, 2004).]