Russian prosecutors have formally ruled that the captain of the Aeroflot-Nord Boeing 737-500 which crashed in Perm was intoxicated by alcohol and negligently caused the deaths of the passengers on board.
The investigative committee of the Russia's federal prosecutor has determined that the captain lost spatial orientation in the final phase of flight SU821 between Moscow Sheremetyevo and Perm on 14 September 2008.
It states that, behind this disorientation, was the captain's "state of mental imbalance" which was "due to the presence of alcohol in the body".
All 82 passengers and six crew members were killed when the aircraft came down on a section of the trans-Siberian rail link, damaging some 500m of track.
The captain's actions "violated the rules of safety and operation of an aircraft" and, because he was obliged to comply with these rules, the prosecutor says he "negligently" caused the death of those on board.
Russian investigators found that the aircraft, which was approaching Perm in darkness and cloud, banked sharply to the left as a result of the disorientation, entering a roll from which it failed to recover.
Investigators partly attributed the accident to differences in the presentation of flight instruments and a misaligned throttle which increased the pilots' workload.