Increased redundancy in airborne systems is very unintuitive. Double redundancy can be more dangerous than having a single system (at least when you're talking engines or sensors anyway).
Triple redundancy is the norm for the specific reason that it's highly likely for symmetrically placed sensors to be prone to failing in the same way not long after each other, but having a third differently placed can keep you flying.
Although there's at least one instance where an Airbus plane had two AoA sensors malfunction at the same time and outvote the last remaining sensor.
This is why critical systems are built with higher degrees of redundancy and graceful degradation of operational envelope in mind.
Training on how to deal with unaided flight is also absolutely essential. Many Airbus accidents where pilot's were caught off guard when the automation that kept them from breaking out of the operating envelope failed.
Long story short; Boeing has put themselves in the unenviable position of having delivered a product in ways that are not only illegal, but deadly, and short of pilots accepting a significant burden in the form of being as good at or better than the MCAS system at this point; a lot of man hours and capital has been expended to end up in a situation where every MAX is in a not inconsiderable risk of being scrapped.
Triple redundancy is the norm for the specific reason that it's highly likely for symmetrically placed sensors to be prone to failing in the same way not long after each other, but having a third differently placed can keep you flying.
Although there's at least one instance where an Airbus plane had two AoA sensors malfunction at the same time and outvote the last remaining sensor.
This is why critical systems are built with higher degrees of redundancy and graceful degradation of operational envelope in mind.
Training on how to deal with unaided flight is also absolutely essential. Many Airbus accidents where pilot's were caught off guard when the automation that kept them from breaking out of the operating envelope failed.
Long story short; Boeing has put themselves in the unenviable position of having delivered a product in ways that are not only illegal, but deadly, and short of pilots accepting a significant burden in the form of being as good at or better than the MCAS system at this point; a lot of man hours and capital has been expended to end up in a situation where every MAX is in a not inconsiderable risk of being scrapped.