So how will this work when none of the instrumentation is giving the computer the correct airspeed? IN the Air France crash, all three of the Pitot tubes had failed.
If /all/ the instruments are incorrect, you might be boned. However, there's gobs of instruments that can be used to paint a partial picture: GPS can be used for altitude and groundspeed in a pinch; there's accelerometers and gyroscopes in place to monitor heading, attitude, and acceleration; and all of these systems are redundant too.
Worst case, add power, level out, and hopefully you'll be stable for a few minutes while the pilots catch up to the airplane.
It can be used to identify when pitot tubes have failed (200kt difference?), and to know that if altitude is stable and the pitch is reasonable that the airplane is in a relatively stable state aerodynamically.
That said, I'm not an aeronautical or control systems engineer, so this is just speculation.
I'm not sure I agree. The speed over the ground means practically nothing from an aerodynamic perspective. You can fly a little Cessna such that it moves backwards relative to the ground if the wind is strong enough.
Once you get to airliner altitudes (say, FL350 and above), the plane does not really want to fly anymore; there is only a narrow band of throttle / pitch inputs that will result in stable flight. You can see this in your favorite flight sim: take a Cessna 172 up to 4000ft and try crashing it. Turn off the engine, cross the controls, and pull the nose up until it stalls. Then release all the controls, and the thing goes back to flying normally with no input from you (and without an engine). Then try this again at 13,500ft in a thunderstorm and see what happens. You can even have engine power. The plane behaves very differently at its service ceiling.
Airspeed data is critical, which is why there were three redundant airspeed systems. Turns out, it wasn't enough.
Pitot tubes, even when jammed, are not the only instrumentation a plane has. In this particular case, whatever gyroscope device is available would probably signal that the angle of attack is completely wrong, tubes or no tubes.
But without Pitot tubes, what indication of airspeed does one have? And without airspeed, I would think that it is the computer that just hit the panic button.
