Originally Posted by KenV
Runaway trim (from whatever cause) can cause loss of control only in a very small corner of the flight envelope (specifically, when slow, at high AOA, and with the engines at high power.)
You've said this before. Have you any proof, or is it a certification requirement? I am sure (never having actually tried it) that if I was doing > 250 KIAS (as they appear to have been doing when level and more in the dive) there is no way (not 737 but medium jet) I could pull enough backstick to hold the nose up if the stab trim was wound full nose-down.