Russian investigators are considering a full-scale experiment to identify the cause of the Yakovlev Yak-42 crash at Yaroslavl, having failed to find an obvious explanation for the accident.
The trijet failed to climb out of Yaroslavl during departure for Minsk on 7 September.
But its take-off weight was below the maximum permissible, said the Russian Interstate Aviation Committee (MAK), eliminating the possibility that the Yak-42 was overweight.
Preliminary information from the flight recorders show that the aircraft was carrying 14t of fuel, of which 8t had been uplifted at Yaroslavl airport.
"Fuel analysis is being carried out," said MAK.
Prior to take-off the crew conducted a check of all flight controls on the 18-year old Yak-42, including that of the elevator. The voices of the crew are being identified on the cockpit-voice recorder, said MAK.
The weather conditions at the airport, including crosswind components, did not preclude the departure. Investigators have already stated that the stabiliser and flaps were set to the take-off configuration, and that the aircraft's engines were functioning until impact.
"The commission has not ruled out a full-sized experiment with an [analogous] aircraft," said MAK.
It said that field work at the scene of the fatal crash, including the retrieval of wreckage from the Yak Service aircraft, was nearly complete.