Speed stability criteria affect the use of Min Drag speed. This is why some jets have a speed-trim function build into the AFDS that is active when flying manual and some even when the autopilot is engaged. So when reducng you Vx you might be faced with chasing your speed with all the effects on the climb gradient.
Good Luck
Last edited by Pitch Up Authority; 9th March 2011 at 14:19.