Originally Posted by
Maninthebar
Good questions, but as I said much much earlier, I think we can turn this one on its head and ask "what enabled the supernumerary Captain on the prior flight to recognise, at least in part, that CUTOUT was the solution?". I believe that, even then, electric trim was re-engaged albeit briefly.
So, even with 3 heads in the cockpit, one of whom was free from immediate control issues, it did not appear to that crew the Trim Runaway NNC was the obvious choice.
I disagree. It appears it occurred to someone (the jump seat pilot) pretty quickly that it was a runaway. They got pitch under control and hit the cutouts. My guess is they re-enabled stab trim in a troubleshooting / curiosity activity (lets see if its still doing it?) because clearly they did not need the electric trim to fly the plane.