Search teams are trying to refine data about the Black Sea crash site of a Russian military Tupolev Tu-154B which came down shortly after departing Sochi.

Specialists are examining air traffic radar data to establish the precise trajectory of the aircraft following its take-off, in order to focus resources more effectively.

Russia’s ministry of defence says the search-and-rescue operation is being “complicated” by a broad range of sea depths and the topography of the sea bed.

Side-scan sonar survey work is being conducted to assist the search effort and define the impact site more accurately.

Eleven casualties of the crash have been retrieved, says the ministry, along with over 150 aircraft parts. The ministry has not indicated that any of these parts include the flight recorders.

Ninety-two occupants had been on board the jet, which was bound for Syria. There is no evidence of any survivors.

The convergence of ships – including several from the Russian Navy’s Black Sea fleet – has brought the total number of vessels to 39, plus seven submersibles and some 135 divers. Overall, the ministry says, there are 3,500 personnel involved in the operation.

Twelve helicopters plus seven aircraft and 20 unmanned aerial vehicles have assisted with monitoring and support, searching over 240km², says the Russian emergency situations ministry.

Source: Cirium Dashboard