Originally Posted by
robocoder
It boggles the mind. So pilots are expected to identify an unknown system as misfiring and at the same time let it do its thing when firing properly.
When it was designed to be active it wouldn't be noticed as it would make the plane act as expected (steady increasing pull needed to increase pitch up). And it was a max of 9s but not always 9s.
But at other times (when not at high AoA) it would appear to be runaway since nothing is expected to run that long. 3 seconds was supposed to be enough to note runaway which suggests auto trim is usually less than 1s. If system cutout in 3-6 seconds you still have a controllable plane.
Level flight and sudden trim like that I'll bet would be noticed. And acted on, though probably not fast/correctly since it's not practiced.
I wonder if any crew would survive a real runaway trim (like a fault in the motor) during take off.
Boeing misjudged the detection speed with all the alarms. They incorrectly assumed the memory items would be followed quickly from memory.
And I think they just didn't consider an AoA failure to high reading during the takeoff phase of flight.
They need to revamp the safety process and the assumptions used in it.