Originally Posted by
yoko1
In the accident scenario, when MCAS was commanding the stab nose down the forces were increasing on the jackscrew mechanism. When the pilots were commanding nose up, the forces were decreasing. If the stab motor was going to stall under an aerodynamic load, it would have happened in the direction of increasing (MCAS), and not decreasing force (pilot trimming). On the contrary, MCAS had absolutely no problem using that one trim motor to drive against an ever increasing force until it hit the physical stops. There is no evidence that the motor was ever overtasked.
I admire your persistency in refusing to even remotely consider it a possibility that the motor could have been overloaded towards the very end of the accident sequences, whilst attempting to move the stab ANU, I am afraid that you have (perhaps inadvertenly) presented an entirely incorrect/reversed description above.
The actual aerodynamic loads on the horizontal stabilizer in the configuration both accident aircraft were in, during the last minutes, would have strongly opposed ANU movements and strongly assisted AND movements. Excerbated further by significant NU elevator deflection.
The 'roller coaster' recovery technique discussed earlier sheds further light on this, as will a quick diagram of forces, if helpful.
KR