I guess PW must be pretty confident that they have the gearbox technology licked - as must Mitsubishi and Bombardier - especially given that, for shorthaul, engine maintenance costs and reliability are at least as important as fuel burn. I agree that RR's third shaft partially addresses speed mismatch concerns but I see that their new offering in this sector (the RB282?) as selected by Dassault for their next gen twin is a two-spool engine. As ever, it's a high-stakes game but IF they pull it off and IF Airbus/Boeing select "conventional" engines for the A320/737 replacement (admittedly both big IFs) it could really put them back in the game - back to where they were when the JT8 was predominant. But I can't see GE or RR taking this lying down - maybe the V2500 replacement will be a GTF with PW doing the fan/gearbox and RR, MTU etc doing the rest?