Originally Posted by electric chris
it seems to be a strong possibility that the pitots iced rapidly due to supercooled water.
Two fragments taken from BEA Report #1; Appendix 1; Meteorological study undertaken by Météo France: Meteorological situation in the tropical atlantic on 1st june 2009 - :
The conditions that are the most favourable to icing (presence of super-cooled water) are generally located in the lower central part of the cumulonimbus "tower", in an altitude range where the temperatures are between 0 and -25 °C. However, the icing conditions can persist down to -40 °C or less, that’s to say up to around flight level FL350, but ice crystals are encountered at this altitude.
the presence of super-cooled water at FL350 was unlikely and would necessarily have been limited to small quantities.
To this can be added that transport category airplanes are designed and demonstrated to be able to cope with large concentrations of supercooled water as can be found at lower altitudes.