malabo,
I am thinking the same. I was a broblem with Pitch-lanes from autopilot in a past. It is funny feeling for take-off or landing when pitch lanes drops off. Other thing is Trim feel. It is very easy to cut it off inadvertentally or maybe jump it over from checklist. This is not a speculation for this accident but it happens to me and our crews in VFR- inland ambulance flights. I can immagine how surprising it might be over the dark sea...
Hostile