There's several subsystems that have backup functionality or piloting fallback available incase of subsystem failure, and subsystems have internal 2-weay or 3-w

There's several subsystems that have backup functionality or piloting fallback available incase of subsystem failure, and subsystems have internal 2-weay or 3-way redundancy/voting. See eg https://aviation.stackexchange.com/questions/15234/how-does-the-airbus-flight-computers-voting-system-work https://aviation.stackexchange.com/questions/15234/how-does-...