Probable Causes
- The flight crew's mismanagement of the aircraft's speed, altitude, headings and attitude through inconsistent flight control inputs resulting in a loss of control.
- The flight crew failure to abide by CRM principles of mutual support and calling deviations hindered any timely intervention and correction.
Contributing Factors
- The manipulation of the flight controls by the flight crew in an ineffective manner resulted in the aircraft undesired behavior and increased the level of stress of the pilots.
- The aircraft being out of trim for most of the flight directly increased the workload on the pilot and made his control of the aircraft more demanding.
- The prevailing weather conditions at night most probably resulted in spatial disorientation to the flight crew and lead to loss of situational awareness.
- The relative inexperience of the Flight Crew on type combined with their unfamiliarity with the airport contributed, most likely, to increase the Flight Crew workload and stress.
- The consecutive flying (188 hours in 51 days) on a new type with the absolute minimum rest could have likely resulted in a chronic fatigue affecting the captain's performance.
- The heavy meal discussed by the crew prior to take-off has affected their quality of sleep prior to that flight.
- The aircraft 11 bank angle aural warnings, 2 stalls and final spiral dive contributed in the increase of the crew workload and stress level.
- Symptoms similar to those of a subtle incapacitation have been identified and could have resulted from and/or explain most of the causes mentioned above. However, there is no factual evidence to confirm without any doubt such a cause.
- The F/O reluctance to intervene did not help in confirming a case of captain's subtle incapacitation and/or to take over control of the aircraft as stipulated in the operator's SOP.
http://www.reuters.com/article/industrialsSector/idUSLDE61M2FE20100223
