Thanks for the responses people. I am only able to provide a 'real' example of the 1900D courtesy of a friend who flies it. The manual states "Vmo is 245 from Sea level to 13500 feet
and decreases to 195 from 13500 feet to 25000". I asume as a similar turboprop (only a bit bigger) that the F50 in the post by omno has the restriction for possibly similar reasons? Have heard of the flutter aspect before but would it be the case for these examples?
Someone must have an idea?
