Originally Posted by
robocoder
Interesting take on the matter. So you're in quite a tight maneuvering spot and suddenly you get a "runaway trim" on top. Which, as the system was undisclosed, cannot look anything else than a genuine runaway trim to the pilots! Or perhaps the idea was that pilots are already used to STS, so trim going its merry way is now unsurprising... for how long?
It seems that in their zeal to leave no pilot error unturned, someone has uncovered another disturbing aspect of MCAS.
Now, for the real questions the above musings raise in a non-pilot (in case some of you have then answers on hand):
- This 3"-seconds-reaction-time-to-runaway figure comes from where? And is it further qualified with "in every possible situation", or "in straight and level flight", ...?
- How long are typical STS bursts?
Very interesting.
So, lets say the pilots mismanages the speed, for example autothrottle disconnected without pilots noticing. Speed decayes, AOA increases, passes MCAS treshold, MCAS start to put in 9 sec of AND trim. So, how should the pilots react now? Should they hit trim cutout after 3 or 4 seconds? How can they know this is a genuine MCAS event and not trim runaway?
This problem clearly needs attention. Something along the lines of a MCAS active aural message, do not hit cutout?