ok
well I want it to be realistic.. no offence and Im sure when the 787 comes out it will be able to or at some point.. but since it isnt out yet....
hope you know what I mean

but thanx for the info

Does you credit, krazyj! But it depends what you mean by 'realistic'? :)
Heathrow/Sydney is not actually all that far by modern standards - it's about 9,400 nautical miles 'as the crow flies'. At the moment pretty well all longhaul airliners are designed to have an effective range of 8,000nms. But 'effective' means carrying a full payload in terms of passengers/cargo.
So Heathrow/Sydney is already possible for existing hardware, if it is not carrying much in terms of a payload. In addition, flying east, if you use 'real weather', you will get the benefit of favourable winds. As a matter of fact, the world distance record for a commercial airliner (10,587nms.) was held (until last week) by a Qantas Boeing 747-400 which flew London/Sydney nonstop on its delivery flight in 1989.
The record is now 11,664nms. and is held by the 777-200LR which flew Hong Kong/London (eastbound) last week.
So if by 'realistic' you mean using an aircraft which is in service, carrying a full load of passengers, and following correct airway routes, it can't be done (not if the aircraft in FS9 are correctly modelled with regard to range, anyway).
But if you care to go into 'Aircraft/Fuel and Payload' and reduce or remove the passenger load, and also download 'real weather', you could probably do it with the default FS9 747-400 as it stands (if it is correctly modelled). Might make a good 'adventure' to try that?

If you want an aircraft that is 'in service', and also one carrying a full load, you'll have to find and download the 777-200LR, and also wait till January 2006 (when it will enter service with Pakistan Int. Airlines). That aeroplane will be capable of Heathrow-Sydney in real life (though it will need extra tanks/reduced load to go the other way).
The 787-9 is 'billed' to have a 'still air' range of at least 8,500 nms. with a full load, and will almost certainly do better than that in practice. So it will be capable of making the eastbound trip as well. The reason that the FS9 version can already do it is that I didn't have to worry about having any fuel reserve on arrival. But it won't be built and flying till 2008 at the earliest!
Anyway, all this has given me an idea - I'm going to reduce the payload of the default 747 and try that nonstop trip myself!
