UtAir aviation flight UT120 crashed on 02.04.2012, at 01:35 UTC (07:35 local time), at day time, under VMC after the takeoff from the Roschino (Tyumen) airport RWY 21.
The АТR72-201 VP-BYZ aircraft, operated by JSC “UTAir Aviation” (further referred to as “UTAir”) crashed while performing the scheduled passenger flight UTA120 from Tyumen to Surgut.
According to the load sheet the A/C TOW and center of gravity were 18730 kg and 30.72 % MAC correspondingly and that was within the aircraft operation limits.
Onboard there were 4 crew members (PIC, F/O and two flight attendants) and 39 passengers, all RF citizens.
After the landing gear and the flaps retraction the aircraft started descending with a significant left bank and then collided with terrain.
The ground collision first led to the structural damage of left wing followed by the fuel spillage and fire, and further to the complete destruction of aircraft with the right wing, cockpit and rear section with empennage separation.
Out of the 43 persons onboard, 4 crew members and 29 passengers were killed.
Others received serious injuries.
The aircraft impact with the ground occurred at 01:34:35 with pitch angle ≈11° nose down, with the roll ≈55 to the left and vertical speed more than 20 m/sec.
The immediate cause of the АТR 72-201 VP-BYZ aircraft accident was the PIC’s decision to takeoff without de/anti-icing treatment despite the fact that snow and ice deposits were present on aircraft surface and were discovered by the crew members during taxi which resulted in degradation of aircraft aerodynamic performance and stall during climbing after takeoff as well as inability of the crew to recognize stall and, consequently, failure to undertake recovery procedure.
The aircraft stall occurred at the operational angles of attack right after flaps retraction with engaged autopilot before stall warning system activation and was caused by the loss of the wing lift effectiveness due to takeoff with non-removed ground icing.
The system cause of the accident were shortcomings in ground handling activities and staff training in UTAir-Technik that became possible because of absence of due monitoring by the Technical and Operation Supervising Directorates of UTAir airline for compliance with airline requirements regarding ground handling and aircraft ground icing protection which resulted in erroneous evaluation of aircraft conditions by the PIC and aircraft mechanic (the shift head kept himself aloof from monitoring mechanic’s activities) after the aircraft has been on ground in icing conditions for a long time and in release the aircraft to fly without de/anti-icing treatment.
Non-execution of measures on de-icing was the consequence of the erroneous coordinated decision of the PIC and the aircraft mechanic who was in charge of the aircraft pre-flight servicing after long aircraft stand under conditions, contributing to the ground icing accumulation of the aircraft.
There was no control of the aircraft mechanic work on behalf of the shift engineer.
The departure of the aircraft with non-removed ground icing became possible due to system shortcomings in the aircraft ground icing protection organization in the Russian Federation, that at the time of the accident was revealed in the absence of the valid basic document, that would determine the regulatory requirements as to aircraft ground de/anti-icing, including the requirements for organizations licensing and training of the personnel that is responsible for the works in question.
The contributing factors were:
- The shortcomings in the UTAir safety management system which contains, all in all, general issues only and is not adopted for the implementation of Airline activities in particular areas, which did not allow to reveal and correct existing safety risks in a timely manner.
- The shortcomings in the UTAir-Technic quality management system, resulted in neglecting of certain requirements of the UTAir ground handling management manual regarding staff training and monitoring for aircraft de/anti-icing treatment which led to the situation when not sufficiently-qualified staff performed the evaluation of the aircraft surface conditions and made the decision on need for the aircraft to be de-iced/anti-iced.
- The absence at the time of the accident of regulations that establish state requirements for ground handling (de/anti-icing treatment in particular) including staff training and organization licensing.
- The shortcomings in crew members initial and recurrent training as far as the danger of ground icing, its influence on the aircraft aerodynamic performance together with aircraft anti-icing system operation features and design are concerned that did not allow the crew to make the only appropriate decision to return for de-icing/anti-icing treatment after the observation of the snow and ice contamination on the wing after anti-icing system activation in de-icing mode while taxiing for takeoff.
- The methodological imperfection of the crew computer based and simulator training programs concerning the prevention of aircraft stall, identification of approach to stall and taking timely actions for recovery.
- The increasing need for number of flight crews to perform highly growing flights schedule which, with ineffective SMS, resulted in flight instructor work deficiencies during PIC training and absence of PIC skills to take correct decisions and to strictly comply with the regulations in force.
- The possible fatigue of the crew members due to the violation of the work and rest balance while performing split flight shifts together with a large number of unused days-off.