The commission investigating the crash of the Tu-154 aircraft is considering seven versions of the tragedy, including human error, technical malfunction, wind shift and bird collision, but there is no priority version, head of Russia’s Air Force flights safety service Sergey Bainetov told TASS on Thursday.
"There is no priority version. There were more than fifteen versions at the beginning of the work. The number of versions has decreased after flight data recorders were analyzed. Now there are half as many," he said.
Speaking about these versions, Bainetov noted that "they are standard and include the human factor, technical malfunction and external factors, such as wind shift and bird collision."
"It is premature to speak about major versions, as any aviation accident is multifactorial implying technical malfunction, human error and external impact," he added.
The crew of the crashed Tupolev Tu-154 plane was prepared for the flight and its skills were consistent with the flight assignment, Bainetov said.
"The flights performed in the nighttime are referred to the category of flights carried out in complex weather conditions. In our estimate, the crew was prepared for the flight and its qualification level was consistent with the fulfillment of the flight assignment," he said.
According to the general, the plane crew commander had a record of about 4,000 flight hours. "He had over 1,500 hours of flying this type of the plane and logged more than 600 hours this year."
The plane was in flight just seventy seconds before crashing in the Black Sea off the resort city of Sochi, according to Bainetov.
"Some emergency developed over just ten seconds, while up to that moment everything had been more or less normal," he said.
"The flight lasted about 70 seconds. The maximum altitude we established on the basis of retrieved flight data was about 250 meters and speed, about 360-370 kilometers per hour," Bainetov said.
At this point, he added, no data is available regarding the angle between the plane’s fuselage and the water surface at the moment of the crash.
The search operation at the site of the airplane crash is still underway as all fragments of the aircraft must be recovered to draw final conclusions, Bainetov said.
"The search operation continues as we need to recover more fragments to conclude the investigations," he said.
The commission expects to find the cause of the tragedy within a month, according to Bainetov.
"In compliance with the rules of investigating air accidents and upon the availability of objective control materials and real evidence, it [this work] takes a month and therefore we expect to find the cause within a month," he said.
"The process is going on and work has begun to lay out fragments as soon as fragments have started to arrive for the commission," he said.
At least ten days are needed to fully decipher the flight recorders of Tu-154 plane, according to Bainetov.
"Work has been going since yesterday for the detailed deciphering and the study of all the materials, which are stored in these recorders. At least ten days are needed to study all the parameters," he said.
As was reported earlier, two flight recorders of the crashed Tu-154 plane have been found. The basic flight recorder has already been delivered to the Air Force central research institute in the Moscow Region while the second black box was recovered from the Black Sea bed on Wednesday.