5 ms·
If you view the MCAS as a control system that is a safety component of the 737 MAX, then you need a really good reason to completely cut off that safety system
by erentz 8y ago
If you view the MCAS as a control system that is a safety component of the 737 MAX, then you need a really good reason to completely cut off that safety system when a particular sensor input goes above a given threshold. In this case the argument being made is that if the input is above 24 degrees the safety system should be turned off, potentially leading to a stall. It's almost an argument against having that system entirely.
The problem is much more complicated than this and requires thinking end to end about 1) what the purpose of the system is, 2) when and how it should operating, 3) how much control it should have, 4) how it's activity is made visible to the pilot when it performs any control, 5) how and under what conditions it should automatically disable itself, or 6) be able to be manually disabled, and 7) how the pilot is made aware of all of these situations in a way that doesn't cause confusion in potentially complex scenarios involving other failures and alarms going off, and 8) proper training so the pilot can manage the plane when the characteristics have changed after the system is disabled. Oh, and 9) in this case since it's impossible for a pilot to manually trim a 737 when it's above a couple of hundred knots, making sure an electronic trim assistance function is available in this scenario (which it wasn't due to tragic idea to overload the use of the trim runaway cutout switches).
And I am probably missing a bunch of things, which is part of the point.