Have read various topics related to this matter but none answer my ponderings. Here goes.
Why is it on (some?) turboprop a/craft once you hit a certain level (ie flight level) that the Vmo starts to
decrease as you approach the maximum operating level?
Have seen for example 230ias to 22000 then reduces to 215 ias by 28000 etc etc.?
thanks for any replies.
