Originally Posted by
Speed of Sound
The diameter of the trim wheel.
Which has been the same size since the 737NG was first produced 23 years ago.
I'm not saying it's not a good idea to revisit this design, but it is not a new design. The fact that it is difficult to use the manual trim wheel in extreme out of trim situations has always been there, but somewhere along the way this knowledge fell out of general circulation and with it an appreciation for the seriousness of runaway trim and the need for flight crews to be regularly exposed to this malfunction and the proper steps to counter it.
To use an analogy, there was a time when the hazards of low-level windshear and microburst phenomenon were not well-appreciated. Now we practice windshear recoveries all the time because prompt recognition and response can be critical to a successful outcome. Why do we not do the same with Runaway Stab Trim? It is a "memory item" after all.