Originally Posted by
esscee
As for using very very old engines, makes me wonder if GE decided that they did not wish to support their old design CF6 for many more years to come which left only PW. Let's face it, they would have only chosen an American built engine after all the
PR "moaning" etc that went on when Boeing did not win in the earlier "contests".
Boeing is still producing new CF6-80C2 powered 767 freighters for FedEx and others - with a planned lifetime of 40 years. As Ken noted, the CF6-80C2 engine is also used on other USAF applications such as the C-5M. GE has committed to supporting the CF6-80C2 for many more decades. We actually took a quick look doing a re-engine for the KC-46 using the GEnx-2B (from the 747-8), but it didn't pencil out well. The GEnx is
far heavier than the PW4000 or CF6-80C2 (close to two tons/engine!), it's over a foot larger in diameter (hence ground clearance/landing gear concerns), and costs about twice as much. Further, while it had much better fuel burn, due to it's much higher weight contribution to the aircraft empty weight, at the same MTOW it's fuel offload wasn't any better for the spec refueling missions than the PW4000 or CF6.
As for a Rolls engined KC-46, the RB211-524G/H that goes on the 767 has been out-of-production for over 15 years - Rolls was never even a possibility. Back when Boeing launched the 747-8, they offered real good pricing on the last 747-400s to fill out the line before switching to the 747-8 production. Cathay came in and ordered six 747-400F, and being a long time Rolls operator wanted RB211-524 engines to be common with their other 747s. That's 24 engines, plus spares - something in excess of $150 million order. Rolls flat said no - they were not interested in building any more RB211 engines. So Cathay got PW4000s on their new 747 Freighters...