Engineer here - trying to look at MCAS out of the box...
So they say, one AoA sensor outputting wrong data alone can activate the MCAS erroneously.
If that is so, which engineering workgroup at Boeing could in their sane minds design such a system, that is supposed to save you from a stall but instead:
- decisively flies you into the ground
- on a calm sunny cloudless day
- with a (except from the AoA sensor) perfectly functioning airplane and engines
- with the same system getting indications for:
- positive vertical (upward) speed within normal margins
- positive horizontal (forward) speed and acceleration within normal margins
- secondary parameters like radar AGL data, GPS groundspeed
- last but not least two pilots, able to look out of the window and able to assess AoA visually
Why would an engineer think it is a good idea to implement such a system that ignores all other available data (which indicates nothing like a stall)? Even if you want to take the pilot/human out of the equation, assuming he put the airplane into an attitude that will result in a stall in the first place, you still have lots of other available data the system can read, that tells it that you are in fact not stalling and that most likely the AoA sensor is telling you nonsense.
Probably the MCAS subsystem will enter the course books of engineering schools, as a textbook example of AS, artificial stupidity, a system designed to be stupid, when you actually need a smart system.
Or are these engineers disciples of the Church of the AoA sensor, since they believe the one and only AoA sensor never fails?
Someone can enlighten me? What did I overlook?