JFK-SYD is well over the Boeing website range for the 789. 8,646 nm vs. 7530 nm. Is the max range they give based on MTOW?
What airframe could Boeing offer to deliver consistently reliable Syd-JFK and return operability with a commercial load? The 777-8 range is quoted by Boeing at 8,750 nm which is just over the Great Circle distance, but what are the air miles flown? Surely you'd need more range than just the Great Circle distance? And that's on paper anyway - fuel consumption might be worse with a plastic rather than paper aeroplane. If the 777-8 ever gets built...
AB is quoting 8,700 nm range for the A350-1000. A strategically-chosen number?