I have followed this thread from the start and some posts suggest that the problem with AF447 (and in many other incidents) may have been caused by an ice blocked pitot-tube. But my question is, Airbus must clearly have tested what a blocked pitot tube would tell the computers to do at that flight level and with that speed? Why is it that I always get the feeling that the FBW software always freaks out when the tubes are blocked and putting the crew in "what the heck is it doing now" mode. There have been so many incidents and crashes in the past by this IAS measuring device so I cannot understand why this still is a problem?
I know that IAS and GroundSpeed are totally different things as the aircraft can be flying in heavy headwind etc, but getting an indication of a sudden drop in IAS from 275 kt to 60 kt must definately be verifiable with GPS data in combination of the known headwind prior to the drop and in that way give the pilots a reading that they have NOT lost the speeds.
There must be another way to measure the aircraft's speed through the wind than just putting the trust in 3 heated tubes that seem to clog more often that wanted.