ATR-42 = 46 seats; max. cruise speed 265kts, economical cruise speed 243kts.
Dash 8-300 = 50 seats; max. cruise speed 285kts.
Fokker 50 = 50 seats; typical cruise speed (for series 300) 284kts.
Of the above, the speeds are roughly the same for the DH3 and F50, whereas somewhat less for the AT4. I am not sure whether the differences would make be noticeable on relatively short flights (1.25 hours and less), and whether they'd be small inefficiencies between the three.
In addition to the above, the ATR-72, with typical seating for 64-70, has a max. cruise speed of 284kts and an economical cruise speed of 248kts. Still, its speed is somewhat less than both the F50 and DH3, but I'm unsure whether it'd be noticeable (i.e. by taking longer to complete a sector) and whether it'd be offset by the increase in seats.
In contrast, the Dash 8-400 cruises much faster (350kts) while seating more people (70). I wonder whether this aircraft would be a suitable replacement for the F50, if an airline wanted to operate a larger capacity fleet and try to increase efficiency (speed is one element which can be tweaked, i.e. by reducing the time to complete each leg, thereby enabling an increase in utilisation by executing more rotations per day). But would it enable an additional rotation per day, in view of the relatively short duration of the flights operated? I'm not sure.
I'm hesitant to suggest a regional jet because of the short duration of the flights and the fact that props can probably do the job just as well - but cheaper.
[Edited 2004-02-20 14:02:46]
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