While reading an article about the Lion Air Crash with a Boing 737 Max 8, I was very surprised by the following paragraph:
In designing the 737 Max, Boeing decided to feed M.C.A.S. with data from only one of the two angle of attack sensors at a time, depending on which of two, redundant flight control computers — one on the captain’s side, one on the first officer’s side — happened to be active on that flight.
My naive assumption was that any system that is capable of pointing an airplane towards the ground would certainly have redundant sensor input, and switch off if there is serious disagreement between the sensors.
Is it common to have non-redundant sensors for this kind of purpose in commercial airplanes?