But graphs I have seen for other jet aircraft transport types do not have that pronounced kink at 20,000ft. What was so different about the VC10?
And as for being outside the boundaries of the graph, remember it is drawn for 1.35g, I've been up to a little over 46,000ft, just between the high speed and low speed buffets in smooth air. Ease the stick forward - a gentle high speed rumble; ease it back a little - the onset of low speed buffet. This was with a certain ex-617 Squadron training captain.