Originally Posted by HN39
But why include such a speed condition?
Because there is a minimum speed below which the required accuracy of the AoA sensors cannot be guaranteed. Even if a lower value had been chosen, the IAS would probably have gone below it.
But that is actually a fouled up design decision. AF447 always had adequate airspeed to properly deflect the AOA sensors on its way down. It was just that the speed sensing system didn't know how to compute for substantially off axis airflow.
Removing the airspeed calculation out of the AOA data is the proper fix. There is no valid reason for mixing the two. They are each independent sources of flight data.
I've flown down to 0 airspeed and observed my AOA data. No surprises.No big deal.
Once airborne, you will never get a jet transport below 60 knots in real life. A weight on wheels type validity is sufficient.