I've been trying to imagine the mechanism by which re-engagement of the autopilot at corrupted airspeed would cause a violent upset. The AP controls altitude, so the first assumption one needs to made is that the altitude at re-engagement differs from the selected altitude. Let's assume it is lower. The AP will then command movement of the elevator control to initiate climb to capture the selected altitude. The AD suggests that the initially commanded movement of the elevator could be too abrupt when the real speed of the airplane is much greater than what the AP 'thinks' it is. The response of the airplane would then be more abrupt than what the AP is trying to achieve, which is, I suppose, a schedule of vertical acceleration and vertical speed. Wouldn't the AP adjust its command before it results in an uncontrollable attitude?
Last edited by HazelNuts39; 25th Apr 2011 at 10:42.