Originally Posted by
EWR764
True, but a PIP'ed GEnx would still lag considerably the SFC of a geared TF. More likely, IMO, would be a 787neo, and a 787-10 that could do East Coast-Asia reliably with full pax and some cargo could be a 'killer app' for UA.
With that said, the A350 is a more capable platform at the 275-300 seat level and there's no question UA has a need for such an airplane, occupying the space between the 787-9 at ~250 seats and shorter-legged 787-10 (~315) and 77W (~350).
The limiting factor for the 787-10, as I understand it, is landing gear, as it is just a simple stretch over the -9 with no way to increase gross weights. If it went to a six-wheel bogie like the 777, it could probably scale up MGTOW and make for a better 77E replacement. But, that would be a significant structural rework, reducing commonality with the rest of the 787s. It would also occupy the lower end of potential 777-8 sales (which is already questionable).
There's a lot of bugs to work out in the scaled up GTF's, look at pratt's mess on the 32neo's IMO it has to mature a bit to that scale. Maybe it will by 2025?
I think UA has shown the williness/ability to adjust frequency rather than gauge on several trunk routes with its flexible 787/777 fleet of late. It's probably a sign of things to come.