&quot;For example, if they had 4 redundant pilot tubes on different places and other redundant methods to measure altitude and airspeed the AP would never have disengaged.&quot;<p>There&#x27;s a lot to be said for that.  The pilots didn&#x27;t know their altitude and airspeed either.  They thought they were overspeeding when they were stalling.<p>Some military aircraft, mostly the stealth ones with terrible aerodynamic stability, need that sensor data to stay in the air at all.  If they lose the sensor data or the stability control system, the only option is to eject.  So they tend to go in for more sensor redundancy. There&#x27;s certainly no reason that large transport aircraft can&#x27;t have more sources of basic attitude&#x2F;altitude&#x2F;airspeed info.