Originally Posted by
mitrosft
I believe that Airbus software is probably missing simple protection in airspeed data readouts. At least manuals in previous posts do not describe any such measures.
If ALL Pitot tubes freezes and IAS deviates by 1-50% then computer before admitting that airspeed data is correct should check the acceleration/decelaration rate from inertial sensors. This simple cross check would protect from any type of tubes failure (freezing, blockage etc)
Don't under-estimate Airbus engineers, 3 sensors, median filters, time delays are all included to minimize false alarms, but what is left is the remote possibility that any 2 may fail in exactly the same way at the same time - so check out the following, especially the 'foreign filing date Sep 23, 2009' :-
United States Patent Application 20110071710 Kind Code A1 Puig; Stephane ; et al. March 24, 2011
METHOD AND DEVICE FOR DETECTING AN ERRONEOUS SPEED GENERATED BY AN AIR DATA INERTIAL REFERENCE SYSTEM
Full text is available on uspto.gov, the "BACKGROUND" section is very clear why such a new idea would be useful.