I note that this a/c is in the COF Aircraft folder but isn't an aircraft selection.  It is missing the Panel folder.  Anyone resolved the problem?

Unlike in FS2002, the AI Dash 8 is quite a flyable plane. You don't need 'downloads' !!!!

Get AirEd.exe from the SimV download section and use it to change the aircraft type from 2 to 0 (about 5th line down or so from the top) so you can see it in the menu.

Then just add a panel and start flying. There are lots of repaints available.

Don't forget that you can also get versions now from Premair (Barry Blaisdell et al) who have re-mapped the default Dash 8 so you get proper paint jobs that don't use mirroring of the textures (simply that means that if you download repaints from the many less experienced painters around you will have back-to-front writing on one side of the plane - not so with their versions).

Hope this helps!