Russia Tu-154 Plane Crash Update: Technical Malfunction Possible Cause, But Terrorism Still Not Ruled Out

The crashed Russian Tu-154 plane had equipment functioning "abnormally," authorities said at a press conference Thursday, but stressed that they have not ruled out terrorism. Sergey Bainetov, the Russian Air Force's deputy head of flight safety, also said that there was no sign of explosion on board the jet, which went down into the Black Sea on Sunday.

The plane almost completely fell apart after it hit the water surface and the seabed, Transport Minister Maksim Sokolov said. The main search operation has ended and recovery efforts for the bodies of the victims are underway. After the complete examination of the crash site, over 2,000 fragments of the plane and 19 bodies and 230 body parts were found.

"Final conclusions on this tragedy will be made after all the data will be collected and examinated," Sokolov said at the press conference, adding that a preliminary report into the crash can be expected in January.

Authorities said that reports of three black boxes of the plane being found are untrue. So far, only two flight recorders have been found and retrieved from the sea floor. Decoding of the second "black box" started Wednesday, and the process may take 30 days.

Authorities said Thursday that some technical malfunction in the plane likely played a role in the crash, but conclusions cannot be made without official results of the investigation, according to Sputnik News.

"It appears that there was a technical malfunction. What is the cause of it is the issue that experts should examine, a special technical commission has been created for this purpose," Sokolov said.

Sokolov also said that the primary objective is to identify victims and that the DNA tests are already underway. However, the process of victim identification may take up to four weeks.

The plane disappeared from radar screens two minutes after taking off Sunday from Sochi in southern Russia. Authorities said that the crash site was located with the help of satellite data.

On Wednesday, local media reports said that the last words of the pilot of the ill-fated jet hint at a wing flap fault as the possible cause of the crash.

The Life.ru news portal said it had obtained a readout of one of the pilot's last words, indicating a problem with the wing flaps. "Commander, we are going down," the pilot was reported to have said. The pilot was also heard yelling: "The flaps, damn it!"

On Thursday, Russian authorities urged media to abstain from publishing an information from unconfirmed sources until the investigation is completely over.

After retrieving fragments of the military plane’s wreckage, authorities determined that an explosion or onboard fire was not responsible for the crash.

"The four main versions are an engine being hit by a foreign object, substandard fuel that caused the loss of thrust on and eventually stopped the engines, the pilot’s mistake and the plane’s technical failure," Russia’s Federal Security Service said in a statement earlier.

Bainetov said Thursday that the crew of the crashed Tu-154 was flight-ready and their skill level was appropriate.

"We have assessed that the crew was ready for the flight and had an appropriate skill level to carry out the task. Commander Maj. Roman Volkov had a 4,000-hour flight time, including a 1,500-hour flight time on this type of aircraft," he said.