Great circle track is around 6615nm on google, Nairobi to Washington Dulles, then alternate on top of that, say Baltimore plus reserves. With experience on big heavy long range jets, this would be in the range of B777-200LR. 347 tons take off weight, around 240 seats in 3 class, up to159 tons of fuel with AUX tanks, it could stay airborne for almost 20 hours, at 490Kts.
But, take off from 5600ft altitude has problems for range on big two engine jet. I have not run the figures at all.
Last edited by Jetjock330; 27th February 2017 at 15:54.