Failure to deice an ATR 72 aircraft which crashed on takeoff on Monday is the most probably cause for the disaster, Investigative Commitee spokesman Vladimir Markin said on Wednesday.
"At this moment, the most likely cause for the crash is the fact that the aircraft was not treated with deicer before flight," he said.
The UTair ATR 72 crashed early on Monday morning on a flight from Tyumen in Western Siberia to Surgut. Thirty one people died in the crash and twelve survived but were severely injured.
UTair’s CEO Andrei Martirosov said on Wednesday that all UTair aircraft would undergo "mandatory" deicing before flight. Previously, the decision on whether or not to deice the aircraft had been left to the captain.
“We decided to acquire the system of procedural limitations on preparing the planes for flight…There will be criteria set up that will require a deicing procedure to be always carried out, regardless of the actual conditions of the plane’s aerodynamic surfaces,” Martirosov said.
UTair’s head also confirmed the crashed plane had not been deiced on Monday.
Martirosov also said “judging by the maneuvers” performed by the plane just before it crashed, the pilots had “fought until the very end” to avoid disaster.
The Russian Air Transport Authority, Rosaviatsia, contradicted on Wednesday previous Russian media reports whch quoted Rosaviatsia’s head Alexander Neradko as saying the aircraft had not been deiced, following a decision by the captain.
According to Rosaviatsia, Neradko said “the plane was not properly deiced before the flight.”
Lifenews quoted the airport's deputy director, Vladimir Nyesmachny, on Monday as saying the aircraft had not been deiced.
“Usually the captain of the aircraft makes the decision, as is his right,” Nyesmachny said. “If he considers that the aircraft needs deicing, specialists are called in. In this case, it was not done,” he said. According to Roshino airport’s standing instructions, aircraft must be deiced if there is any precipitation at the time of take-off.
Icing can take place in a temperature band from minus 12 to plus 4 Celsius. There was no rain or snow overnight on Monday at Tyumen’s Roshchino airport in the hours leading up to the crash, but temperatures were around zero and visibility was low due to high humidity according to local weather forecasts.
Icing has also been attributed as the cause of two earlier fatal crashes involving the ATR 72.
