I came across this old thread while trying to solve the same problem myself.If anyone still needs to fix this the solution is two small edits to the Aircraft.cfg file:In the [General] section,Change atc_type from Beechcraft to BEECHChange atc_model from B33 to BE33ATC will then correctly refer to "Beechcraft Bonanza" and use callsign "Beech nnnnn" .Hope this helps someone.