In-depth. Official cause is “pilot error following incorrect pitot readings.”
Correspondence between Airbus and Air France reveals that both manufacturer and operator were knowledgeable of the pitot issues, and that both were pro-actively trying to find a solution:
In July ‘08, the first “faulty reading” was reported to Airbus by AF.
At the end of March ‘09, AF experienced and reported their first “faulty reading” with the A330.
In April ‘09, Airbus stated that the icing phenomenon involving ice crystals was a new phenomenon that was not considered in the development of the Thales C16195BA probe and offered in-service evaluations to AF.
The crash occurred less than one month later, just as Air France’s A320 fleet started receiving new probes.