Originally Posted by
infrequentflyer789
Only trim in the opposing direction is stopped, and all electric trim in the opposing direction is stopped. The only way to trim forward whilst pulling back would be manual trim wheel.
Not all opposing electric trim is stopped. Only main electric (control wheel switch) and autopilot trim. STS is not the autopilot.
And you can also use the control-column-actuated-stablizer-trim-cutout-switch override switch.
This is one of the simplest and neatest examples of Boeing philosophy of helping the pilot not do stupid but never by overriding the pilot's primary control inputs.
So, the design philosophy is, "Don't let the pilot do anything stupid. Unless he does something stupid with the primary flight controls. Then, don't interfere."
This was a good system, but not any more. MCAS broke the system. Now there is another way to trim forward whilst pulling back - just let HAL do it for you, all the way down.
Well, the whole raison d'être for MCAS is to modify stick forces when pulling back, so obviously it needs to be able to trim against stick deflection.
And if you insist that something "broke" the column cutout switch design philosophy, STS did it first. It also trims against stick deflection, explicitly to "increase control column forces".
Bernd