If you want to read the full 200+ page report, look here:
http://www.bea.aero/en/enquetes/flight.af.447/rapport.final.en.php
You can also peruse the Flight Data Recorder readouts and the full transcript of the Cockpit Voice Recorder.
It appears that the pilots did not follow the "Unreliable Speed Indications" emergency procedures. The report also indicates that this emergency procedure isn't presented that often in training.
A number of factors are believed to be related to why the pilots kept the aircraft nose up.
- It is possible they thought the aircraft may have been in an overspeed condition (based on statements recorded on the CVR)
- The stall recovery procedure immediately after takeoff involves keeping the nose at a 12-degree nose up attitude, and the pilot may have reverted to that thinking even though that approach doesn't work at high altitudes/airspeeds.
- The flight director on the primary flight display kept directing a nose up attitude; the emergency procedures specifically say to deactivate the flight director in the event of unreliable speed indications.
It also appears that the pilots ignored the repeated stall warnings, even though the stall detection system is linked to the AOA sensor and would be unaffected by a loss of the pitot-static system.