"A factor in the development of a special situation in the flight could be the wrong data about flight speed on pilots' indicators which was likely due to iced pitot tubes (speed probes) while their heating systems were shut off," said the Russian Interstate Aviation Committee (IAC) which investigates aircraft incidents.
The Antonov An-148 plane took off from Moscow's Domodedovo airport on Sunday to the Russian city of Orsk and went down in a field around 70 kilometres (40 miles) southeast of Moscow shortly after. All 65 passengers and six crew members on board died.
The IAC said it has completed analysis of the on-board flight recorder and would still need to analyse the black box which recorded conversations in the cockpit. It would also look at whether the pitot tubes, a vital piece of equipment which measures airspeed, could have malfunctioned.
Iced-over pitot tube instruments were previously named as the likely reason behind the Air France 447 flight crashing into the Atlantic in 2009, killing 228 people on board.
The plane's autopilot was turned off and it began to sharply lose speed until impact with the ground at 1127 GMT, the IAC said.