Hi,
lomapaseao
I believe that you are too quick to defend the pitot tube as not being at fault. The earlier poster had specifically stated "pitot system"
It was the speed measuring system at fault (the pitot was only a part of it). Of course you are correct that such a system fault was presumed at aircraft certification..
The Pitot tube is not only a part of it ..
it's the most important part of it
Remove from the plane the Pitot tube and you have no more speed measuring system at all
The AF447 case proven this.
The best solution at today date is to use the Pitot tube in his domain of certification
So .. dont fly in ice crystal area ..
If not able to detect ice crystal .. don't fly in the areas when this is the possibility to meet them .. forget fuel sparing .. fly safe !