Hi, found this thread whilst trying to do some research into possible alternatives to the Twin Otters operating out of St Mary's.
The local authority have just published a report on works at the airfield (primarily to resurface the main runway) but they investigated extending the runway to 1000m (not going to happen).
I remember being told that a Dash 7 would in theory be able to operate if the extensions at either end of the runway were widened to full width - bringing the runway length to 690m.
Having done some more reading (and speaking to someone that had Dash 7s advertised for ACMI lease) it seems its just not an option (not least because there just aren't any in the EU - but also because they would likely need to apply EASA-OPS meaning they would need 1000m anyway)
If anyone is interested, the report is here. (note I am NOTHING to do with either the authority, the airport or the airlines, just a resident who relies on the transport link to commute.
http://committees.scilly.gov.uk/mgCo...px?ID=629&T=10
As an aside, someone did bring a Dash 7 in for an Air Show when I was a kid, they landed it and it stayed most of the day for people to look at and left in the afternoon. I believe it was a Brymon one (they were still operating the Twin Otters on the route at the time).