> 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.
The theory is if one computer fails due to bad data from a faulty sensor, you've got another computer ready that hasn't seen said data [1]. It'd be pretty bad if bad data from a single sensor broke both computers at the same time.
Obviously, the Lion Air flight did crash, so this no longer seems like such a wise design.
> 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.