Interesting points and all good stuff.
To re-iterate the original question, exactly where is it written that you shall not operate below these magic speeds. They are extremely useful, and as others have wriiten, give a very good clue as to how hard the wing is working, and what sort of margins you have left before things would become very interesting.
HOWEVER, top of the amber on the airbus is VLS, which is the lowest selectable speed avaible to the crew, AT THAT CONFIGURATION. Bumbling around northern europe at relatively modest weights,in an A319, there's normally a huge spread between any one of the early markers, green dot or F speed for config 1 or 2 especially, and VLS.
If fifi the wonderjet shows us exactly what that speed is, why can't we use it?
Airlines or manufactures?
Intrigued
