The flight 447 departed from Rio de Janeiro at 22:29 UTC scheduled toarrive in Paris at 09:03 UTC. The last contact of the aircraft with land was at01:35 UTC. At around 02:06 UTC, the aircraft entered the area of the thunderstormand was having a constant turbulence. After passing through the storm for 2 to3 minutes, the aircraft experienced the icing conditions and anti-icing systemof the craft came on. This was also when the ice crystals also started to blockthe pitot tubes. At 02:10 UTC, the auto-pilot system of the aircraft turned offbecause the correct readings of the air speed were not being received anymoreas by this time the pitot tubes had been completely covered and blocked by icecrystals.
Due to the shut down of auto-pilot system of the aircraft, the auto-thrustsystem disengaged as well and the aircraft started to move left because of the turbulence.This was when the pilot used the side stick to control the aircraft and keep itsteady. For the next 30 seconds, the aircraft moved from left to right and thepilot also brought the aircraft in the nose-uplift position which was unnecessaryin that situation. At the same moment, the aircraft stall warning started soundingdue to the angle of attack exceeding the limit of tolerance. The pilot kept thenose up position of the craft for the next 30 seconds and with the speed thathe was at, the aircraft was climbing with 7000 feet a minute. The left-sideinstrument had also malfunctioned and was giving incorrect readings of theaircrafts speed showing a sharp increase in the speed. At 02:11 UTC, theaircraft had reached the maximum allowed altitude for an Airbus A330. At thatmoment the angle of attack was 16 degrees but as the aircraft starteddescending the angle of attack reached to 30 degrees.
At this moment, the stallprotection system was not working either. Hence, the lift was lost by the wingsand the aircraft stalled.