What happened
On April 2, 2012, an ATR 72-201, registration VP-BYZ, was performing a flight at Roschino aerodrome in Tyumen. During the approach to runway 21, the aircraft experienced a significant cross-track deviation of approximately 40 and crashed roughly 1,500 meters from the runway threshold. The accident resulted in fatalities.
The investigation
The investigation focused on the aircraft's aerodynamic performance and the conditions of the aircraft prior to takeoff. Investigators examined the flight history, meteorological data, and the effectiveness of the de-icing/anti-icing procedures applied at the aerodrome. The inquiry also reviewed the crew's training, fatigue levels, and the maintenance of the aircraft's ice protection systems. Technical analysis included engineering simulations and flight simulator tests to evaluate the aircraft's behavior during critical flight modes and the impact of surface contaminants on the horizontal stabilizer.
Findings
Significant findings from the investigation revealed that the aircraft's surfaces were contaminated with ice or frost. The investigation established that unremoved contaminants on the horizontal stabilizer contributed to a change in pitch forces, leading to an aerodynamic stall. Furthermore, the investigation identified failures in the airline's safety management system, specifically regarding the oversight of ground handling services and the adequacy of de-icing/anti-icing procedures. The crew's ability to recognize and recover from the resulting critical flight modes was also a factor, as training procedures for such scenarios were found to be insufficient.