From series II: (last night)
26th May 2011, 22:21 #2518 (permalink)
llagonne66
GB
I beg to differ on your comment.
QUOTE
Just maybe Airbus squeezed the specs just a little too tight, and ended up with pitot that are fine nearly all the time, but without enough reserve
heating energy for every case of high altitude icing conditions.
UNQUOTE
Please go back to BEA interim report #2 page 63 :
QUOTE
The set of icing tests to be performed to meet the Airbus specification includes 26 test points in all (10 for covering appendix C and 16 additional tests), thus covering a wider envelope than that defined by the JAR25 regulations.
The Airbus specifications used for the certification of the probes are therefore stricter than those of JAR 25 (annex 4).
UNQUOTE
We don't know by how much margin they passed the tests, or whether deterioration of either the probes or the power supply or wiring have been a factor. We do know the pitot on the A330 have not always been robust enough for real life icing.
We also know that the computers were not robust enough to accommodate erroneous airspeed.
GB