Would it not have more to do with simultaneous ice pack of 1 and 3?
One and three have more in common in asymmetric airflow. No?
From a statistical point of view, cruise flight would generally represent most of the aircraft's exposure to symmetric airflow. In areas where particulate water Ice is present, a very small portion of total time in cruise, Ice is associated with turbulence, hence a higher chance that Ice would hobble vanes and pitots when unstable air is encountered. This suggests a higher probability that pitots located in close proximity would fail simultaneously.
Chris Scott:
"Can anyone cite an accident prior to AF447 that was related to the icing of a properly-heated pitot probe or AoA probe? Right now, I can't think of one, nor of a type that regularly experienced UAS problems in any flight-phase."
Not an accident, no. Incidents? Of course.... The AD is a place to start, re Thales.
Last edited by Lyman; 6th Jan 2013 at 16:22.