Pilot error was likely involved in the crash of a Russian-made Sukhoi Superjet 100, RIA Novosti news agency reported on Friday.
The agency quoted Izvestia daily’s reports that the trials, held at a pilot training center in Zhukovsky near Moscow had simulated "various emergency situations and concluded that none of those could have been behind the crash.
A source at the center who declined to be named said that analysts concluded that the plane’s cockpit Terrain Awareness and Warning System (TAWS) would have informed the Sukhoi pilots’ if the plane was approaching an obstacle.
"You just cannot miss the alert signal: if there is a danger, the system puts an alert message onto the central display, and a red light indicator as well as a speech alert come on," the source said.
"Besides, automatic systems can intervene to try to help the plane avoid a collision."
The source suggested that the pilots might have turned off the alert system in order to speak with passengers or to show them around the cockpit.
The agency quoted another expert at the center as saying that the pilots might have "stopped taking notice" of the alert system as it is "nearly always on" in mountainous regions.
However, other flight safety experts dismissed the Russian analysts, saying that their tests had not given “a complete picture.”
“Tests in a simulator do not tell the whole story,” an unnamed expert from the Russian State Scientific Research Center for Civil Aviation told Prime News agency.
“Tests with a real aircraft are possible only after the discovery and decoding of the aircraft’s flight data recorders.”
Another expert agreed with the Russian experts that a failure of the aircraft’s Terrain Awareness and Warning System would be critical.
“There are three possibilities: the first is that it was not working, the second that it was turned off or they didn’t pay attention to it, or that it gave an erroneous indication,” he said.
On Thursday, Russia's acting Deputy Prime Minister Dmitry Rogozin said experts believed "human factors" were the most probable cause of the fatal crash.
"Experts say that all [the aircraft's] equipment functioned smoothly. In other words, it could be some kind of a human error," Rogozin told journalists.