Russian investigators have concluded that a lack of adequate training in handling the Tupolev Tu-154 tri-jet at high altitudes and angles of attack led a Pulkovo Airlines crew to stall their aircraft and enter a fatal flat spin.
The aircraft, operating the domestic Anapa-St Petersburg route on 22 August last year, failed to recover from the spin and, at a high rate of descent, struck the ground near Donetsk in Ukraine.
All 170 passengers and crew on board the Tu-154M, registered RA-85185, were killed in the accident.
During the flight the jet had climbed to high altitude in the vicinity of turbulent thunderstorm activity, and was subjected to pitch changes that took it beyond the stall limits.
Russia’s Interstate Aviation Committee (MAK) says the crew had not received sufficient training or simulation experience on the specific procedures, including use of the trim control, necessary to maintain longitudinal stability under these conditions.
“Absence of control over the airspeed and the non-compliance with flight operation instructions to prevent the aircraft’s entry into a stall, with unsatisfactory crew intervention, made it impossible to avoid transition to a catastrophic situation,” says MAK.
The organisation has already made several recommendations to improve pilot training and has urged crews to take account of operational limitations when selecting a flight path to negotiate storm cells.
During the inquiry MAK conducted simulations and test flights to examine the behaviour of Tu-154 aircraft at high angles of attack, in a bid to determine how the emergency developed. Investigators also closely studied previous similar accidents involving Tu-154 aircraft, including the loss of an Aeroflot flight in July 1985 over Uchkuduk in Uzbekistan.
St Petersburg-based Pulkovo Airlines has since merged with Russian government carrier Rossiya under whose name the combined airlines operate.