Originally Posted by mm43
As HN39 has mentioned, the likelihood of ice crystals above FL300 and less than -40 deg C wasn't considered.
That's not what I said or meant. The Airbus requirement (ice crystals) in your diagram covers the atmospheric conditions of AF447 (FL350; SAT -38.8). I was thinking about obstructed static ports, blocked pitot drain holes combined or not with blocked pitot 'intake', in various phases of flight. Sorry if that wasn't stated explicitly.