MOSCOW, December 29. /TASS/. 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.

Tu-154 crash

A Tu-154 plane from Russia’s Defense Ministry crashed in the early morning hours of December 25 shortly after taking off from the Black Sea resort of Sochi.

There were 92 people on board the aircraft, including eight crew members and 84 passengers that lost their lives in the plane disaster. Among those on the fatal flight was the Executive Director of the Spravedlivaya Pomoshch (Fair Aid) charity fund, Elizaveta Glinka, better known to the Russian public as Dr. Liza, as well as military servicemen and nine reporters from Russia's Channel One, Zvezda and NTV networks.

The plane was also carrying nearly three dozen members of the world-renowned Alexandrov Ensemble, an official army choir of the Russian Armed Forces. The ensemble was on its way to celebrate New Year’s Eve with Russia’s Aerospace Forces at the Hmeymim air base in Syria.

The Russian Defense Ministry said that fragments from the Tu-154 disaster had been discovered some 1.5 kilometers off the coast of Sochi at depths of 50-70 meters. None of the passengers on the flight survived.

According to the latest data, 15 bodies and 239 body fragments of the crash victims have been recovered from the seabed.

Transport Minister Maxim Sokolov who heads the government commission for the investigation of the plane crash has said that a terror act is not among the accident’s basic versions.

Russia’s Federal Security Service (FSB) said on Wednesday that four basic versions were considered: outside objects getting into a plane engine, inferior fuel, pilot error and the plane’s technical malfunction.