Engineers don't make decisions like this. Not providing documentation of the feature or providing training to pilots was the problem, and it's caused by multiple management failures. The lack of sensor redundancy likely also is due to management.
The lack of sensor redundancy HAD to be signed off by a professional engineer. It doesn't matter if management pushed it; it's the engineer's (PE's) responsibility to refuse to sign off on it.
I’m not convinced sensor redundancy is the issue. The plane has two sensors; for some reason, however, the package that includes the AoA disagreement light costs extra.
It seems that lack of training and documentation was the reason these planes crashed though. The pilots didn’t know how to recognize the issue or resolve it.
