Scott Hamilton just came out with this story: the A350-1000 will get more range (500nm) and a more powerful Trent XWB engine (+5000lbf).
A quick calculation revealed that 500nm more range need about 12.3t more MTOW. About 10 tonnes are for the extra fuel burned to cover the extra 500nm, about 2 tonnes needs the structure to carry the heavier aircraft, the balance goes for fuel reserves, as these are calculated in dependence of the actual flown range.
Thrust-to-weight ratio thus will be largely unchanged, runway performance probably a little bit worse, if the wing is unchanged. Compared to the B777-300ER, the wing is not heavily loaded, so I do not believe Airbus will enlarge the wing.
Scott writes that even the 8500nm will not meet Emirates desire of being able to fly Dubai - Los Angeles nonstop. The great circle distance for DXB-LAX is about 7250nm, so there is a 17% range margin. But is this enough to counter strong headwinds. A quick calculation shows that 17% of Ma0.85 (cruising speed of the A350) are equal to about 83nm/hr, meaning that if the average headwind on the route is higher than 83 knots, a technical stop would be necessary. I do not the average wind speed on the route over the north pole, but I could imagine that average wind speeds of 83knots and more ar possible.
The calculation also confirms that Emirates second desire - to add more pax - cannot be part of the change in the A350-1000 specification. So I wonder what is the rationality behind these changes? The 777-300ER has slightly less than the 8000nm of the "old" -1000 configuration, the 500 extra miles is good for a couple of extra city pairs, but does that justify the pain? The pain is probably bigger for RR than for Airbus, as these 5000lbf more of thrust will very likely mean that the whole core has to be changed, which means a lot of investment.
The main reason for that change might be to prevent Boeing from concentrating on the B737 successor. Airbus might hope that Boeing now feels more pressure on the B777-300ER and to concentrate R&D resources here and "only" to re-engine to B737 as Airbus always predicted.
And Airbus is apparently not alone: the recent Bernstein Research Note also suggests that Boeing should re-engine. Richard Aboulafia, VP of Teal Group, also thinks that a B737RE is the best answer to the A32XNEO, as one can reread in the AirInsight Paris Airshow Discussion transcript.
I guess we can expect the official Airbus announcement on Saturday, June 18th at the press briefing.
One is for sure - this years Paris Air Show is getting more and more interesting.