Recent posts have considered pilot performance in recovering the aircraft using the ‘roller coaster’ manoeuvre. The accidents indicated that this was not possible due to high elevator forces and inability to move the trim wheel.
The out of trim condition and forces in the accidents were higher than might be assumed due to feel shift, because of the stall warning from false AoA.
With a trim runaway, independent of stall warning, the crew might be able to overcome the lower forces and use the ‘roller coaster’ manoeuvre.
Dave, the point being considered is an emergency where the trim has been isolated as part of the trim runaway drill.
Also, an EASA certification query implied that electric trim would not be available, and not considering higher non-normal tail angles.
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The main issue being that longitudinal trim cannot be achieved throughout the flight envelope using thumb switch trim only”
“Boeing set the thumb switch limits in order to increase the level of safety for out-of-trim dive characteristics”
https://www.easa.europa.eu/sites/def...20ISS%2010.pdf