Originally Posted by
Station Zero
I have been thinking further about what possibly caused the increase forces, as aerodynamic forces should not really be felt even on a 737 through the column unless the hyds are off, so could the Elevator Feel Shift that occurs when a stall is detected (I believe based on AOA input to the SMYD) be the cause of the increase of column forces, as this applies forces to the feel and centering unit to resist elevator up movement which could have effectively compounded the situation.
That's what I would expect as well, based on what I've heard happened some time ago on a 737NG aircraft. In that occurrence a damaged AoA vane resulted in erroneous airspeed indications, continuous stick-shaker, a FEEL DIFF PRESSURE warning and abnormally heavy control forces (especially noticeable during the flare). It certainly seems possible that in this Lion Air accident higher control columns due to FEEL DIFF PRESSURE compounded the situation caused by the automatic mistrim.