Originally Posted by
Lyman
the PF wanted to climb, and may have not anticipated a lock out of the Autotrim with a robust Pitch UP. So he kept increasing input (NU), and the a/c started to climb
[...]
I am convinced that some variation of this is what started the problem. What cause dit to be ultimately insoluble is left to others.
Look at the report. The trim does nothing until the a/c is at top of climb and proabbly already stalled. It does nothing because it didn't have to - small elevator movement was enough. Only as it becomes increasingly difficult to maintain the (impossible) climb does the elevator start to move significantly NU and the THS follow. There was no lockout of autotrim. Look at the traces.