Russian investigators say flight recorders from the air crash that killed the President Lech Kaczynski of Poland show pilot error was to blame.
A report from Moscow says first analysis of two black boxes from the jet, which crashed in heavy fog near the city of Smolensk in western Russia, showed the crew were unfamiliar with the plane's handling.
A third black box is being examined in Poland.
The aircraft was carrying Mr Kaczynski, his wife Maria, and 94 other prominent members of the Polish government and the military to a World War II memorial service.
A state funeral for Mr Kaczynski and his wife will be held on Sunday.