(Rick Ludtke, a former flight deck integration engineer,)
“In our department, we never designed anything without comparators,” meaning monitors that compare independent sensor readings and de-activate the system if they disagree, he said. “Curtis, I know, had several types of comparators in that synthetic airspeed system.”
https://www.seattletimes.com/business/boeing-aerospace/boeing-whistleblowers-complaint-says-737-max-safety-upgrades-were-rejected-over-cost/