Originally Posted by
TryingToLearn
In case of an important 'warning' function you may want something fail-operational, your safe state is 'warn'. So you place an 'OR' logic within your redundancy. In case of a -maybe dangerous- reaction and a fail-safe ('better do nothing') system, AND is the only solution.
Next question, where is MCAS?
Again, just speculating. According to initial reports, MCAS was only supposed to make a 0.6 nose down input. That is entirely manageable and wouldn't pose a threat, particularly if it occurred only once. Multiple 2.5 degree nose down inputs is an altogether different story. We don't why this change to MCAS authority was made, but apparently someone didn't connect the dots.