02 июля  Ми-8Т RA-22599

     The Interstate Aviation Committee Investigation team which included official representatives of Rosaviatsia has completed the investigation of the fatal accident with Mi-8Т RA-22599 helicopter operated by "UTair" Aviation" JSC occurred in the area of exploratory well №774 of Vorgenskoye oil field on 02.07.2008.
     Final report in accordance with the investigation results was signed by all members of the Investigation team without comments and dissenting opinions.
     According to the investigation team's conclusion:
     "Fatal accident with Mi-8Т RA-22599 helicopter was caused by hard helicopter landing with high vertical and unbalanced forward speed that resulted in main gear box shift from regular place, kinematic decoupling: main gear box - engines resulted in engines free turbine rotor spin-up to their destruction and extensive fire in engine bays and helicopter cargo-passenger cabin.
      Helicopter hard landing was caused by one of the following factors or its combination:
- possible change of wind vector and force indicated by windcone; 
- possible excessive helicopter landing weight for these landing conditions;
- possible crew actions failure during landing resulted in late and dynamic main rotor collective pitch increase that resulted in main rotor speed decrease below minimum and helicopter mush;
- possible failure of an engine with partial power loss during helicopter landing. 
Factor compounded the accident severity is lack of cargo-passenger cabin protection of Mi-8 helicopter from unlocalized destruction of engines free turbines that resulted in rapid fire spread from propulsion sections into cargo-passenger salon and passengers fatalities".
      The Investigation team conducted investigation of the accident causes with senior and flight personnel of the Airline and recommendations on flight safety development were developed.