Originally Posted by
Airbubba
Or, were the column forces in pitch so great with the stab trim switches off that the crew turned them back on momentarily to retrim, not realizing that they could trim manually with the trim wheels?
Airbubba, see the video posted on Leeham news. They're simulating a high-speed runaway stabiliser after an unreliable airspeed event. The cut-off switches are thrown at roughly 3 degree ANU and 310 knots, and it is almost impossible to get the aircraft back in trim using manual trimming whilst the PF is holding almost full-aft stick. And this was at 3 degrees ANU, the ET crew was facing a stabiliser trimmed much further nose down. In short, it's physically impossible to get the aircraft back in trim manually without unloading the stabiliser, which require a lot of airspace between you and terra firma.