As ever a thought provoking post from you Centaurus.
A couple of random thoughts..
I seem to recall way back that the stab trim setting was only valid for a full thrust take off. Not sure if that was in the FCOM, FCTM, or a Boeing performance or loading manual. If true then any de-rate, either fixed de-rate or ATM de-rate means the stab trim setting is not optimal.
I also seem to recall a Bulletin advising that the installation of winglets also rendered the stab trim setting inaccurate, though I believe that may have been resolved.
In any instance as you point out there always seems to be a "null" point during rotation and one nearly always ends up "blipping" some aft trim after T/O!
Last edited by Capt Chambo; 21st May 2015 at 23:04.