According to preliminary results of the investigation, the accident with the UTair aircraft ATR-72 was the result of the deterioration of aerodynamic characteristics of the wing and stabilizer as a result of the ice not being removed while preparing the aircraft for the flight after a long (8h) overnight stay in icing conditions (freezing rain, and the transition of temperature below 0°C, the wind 7, gusts of 10 m/s).
The investigation of the crash of the ATR-72 VP-BYZ identified deficiencies that lead to the conclusion that the preparation of the aircraft for flight was made in violation of the rules by ground staff of "UTair-Technik", which was to conduct de-icing of the aircraft, and by the crew, which did not assess the state of the aircraft surfaces and meteorological conditions during the overnight stay of the plane at the airport Tyumen.
In the process of making the decision, that de-icing is not necessary, also participated an aircraft mechanic, who had no aviation education and had been working in "UTair-Technik" for little more than one and a half year. Aircraft mechanic was admitted to ground handling services after 16 hour training courses, of which to the theory of ice control and the de-icing of the aircraft were dedicated only 30 minutes. The supervisor of the shift, who should have controlled the aircraft mechanic's work, was on a nearby parking lot, located next to the plane. Having received the information, that the de-icing of the aircraft was not carried out, the supervisor didn't intervene.
The violations in the ground staff's work also point out that, despite the introduction of airline standards similar to accepted overseas, the necessary quality control system is practically inactive.