Flight data recorder recovered from crashed Russian military plane
Investigators have recovered the flight data recorder from a Russian military plane which killed all 92 people on board after it crashed only moments after take-off.
The Tu-154 ditched into the Black Sea early on Sunday two minutes after departing in good weather from the city of Sochi.
The plane was carrying members of the Alexandrov Ensemble, widely known as the Red Army Choir, to a new year's concert at a Russian military base in Syria.
Meanwhile, rescue workers raced to wrap up their efforts to recover bodies and wreckage ahead of predicted bad weather.
The work has involved 3,500 people, including about 200 navy divers flown to the site from all over Russia.
Aided by drones and submersibles, teams have recovered 12 bodies and numerous body fragments about a mile away from the shore.
The main flight recorder was quickly flown to Moscow, where experts started analysing it, transport minister Maxim Sokolov said.
Preliminary findings could be available as early as Wednesday, according to some aviation experts.
Investigators were looking into whether the crash might have been caused by bad fuel, pilot error, equipment failure or objects stuck in the engines.
The top Russian investigative agency, known as the Investigative Committee, said it had taken samples from a fuel tank used to fill the plane, which flew from Moscow's Chkalovsky military airport and stopped in Sochi for refuelling.
The committee also said it found a witness who filmed the crash.
Online publication Life.ru published what it described as a script of cockpit conversation, with one pilot yelling about a problem with the plane's flaps and then shouting: "Commander, we are falling!"
It was impossible to verify the report but Life.ru is known to have good connections with Russian security agencies.
Flaps are moveable panels mounted on the edge of the wings to increase lift.
The Interfax news agency reported the flaps were not functioning in sync, causing the jet to lose speed and triggering an aerodynamic stall.
It also said preliminary analysis of the flight recorder pointed at pilot error.
The government has sought to quell speculation the crash might have been caused by a bomb planted on board or a portable air-defence missile.
A terrorist attack on a Syria-bound military flight would badly embarrass the Kremlin at a time when it boasts about the success of its campaign in Syria after Aleppo fell into President Bashar Assad's hands.
Russia's main domestic security and counter-terrorism agency - the FSB - said it found "no indications or facts pointing at the possibility of a terror attack or an act of sabotage" on the plane.
However, some aviation experts have noted the crew's failure to report any technical problem and the large area over which fragments of the plane were scattered point to a possible explosion on board.