The pilots were never trained to handle precisely such an emergency at high altitude, according to safety experts and a previous report by France's Bureau d'Enquetes et d'Analyses, which is heading up the investigation. All 228 people aboard died in the accident.
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Though Friday's announcement won't provide final conclusions or specific causes, investigators believe Air France never trained its pilots to cope with such automation problems in conjunction with a high-altitude aerodynamic stall, an emergency when the wings lose lift and the plane quickly becomes uncontrollable.
From the article.