Originally posted by pacerr: The factors at play in choosing a commercial aircraft are fascinating -- pick a route structure, a payload (250-475+ seats?) and a required range (9000- to 19000 KM?). There's a whole world of difference in the numbers when you factor in a mission statement and the variable trade-offs in payload, fuel economy, route structure, predominate weather, etc. E.g., sometimes you give up economical fuel burn to increase speed to get that last available gate time at a hub. Or to squeeze in an extra trip per day on a popular route where assured full seats offsets fuel cost.
Right, so in the same way that 747-400 did a London-Sydney flight direct with only crew on board, but couldn't do it safely with passengers, luggage and freight. Qantas is asking the aircraft manufacturers (presumably Boeing and Airbus) to deliver an aircraft capable of a London-Sydney direct flight, presumably with a reasonably standard seat layout and capacity. It's interesting that they haven't done a London-Sydney delivery flight for a 787.
Quote: As a MUCH simpler example, in my 7KCAB with 36 gallons of no-reserve fuel the POH says I can go 390 sm @130 mph @ 2500' MSL burning 11.6 gph in 3.0 hrs OR 815 sm @90 mph @10,000' MSL burning 3.8 gph in 8.5 hrs OR most anything in between those numbers. However, there's only 540 lbs of total discretionary payload to be divided between two seats and fuel which weighs 6 lb/gal. (In practical terms, however, my personal 'holding tank' is only good for about 3 hrs max in any case which tends to 'define the mission plan!)
It makes sense to take a conservative approach and keep an eye on the fuel gauge.
And to have a functioning fuel gauge (
Gimli Glider - Wikipedia)