The Su-57 fighter jet that crashed on Tuesday in the Far Eastern Khabarovsk Region had entered a downward spiral at the altitude of 8 km and the pilot’s attempts to fly out of it failed, a source in the aircraft construction industry told TASS on Wednesday.

"The Su-57 was performing a test flight at the altitude of 8,000 meters. After the control system had failed, the fighter jet spontaneously entered a downward spiral and started descending and then crashing," the source said.

According to the source, the pilot tried to switch the aircraft to a horizontal flight in a manual mode, but his efforts failed. "At a critical altitude of 2,000 meters the pilot decided to eject," he said.

On Tuesday, a source in the defense industry told TASS that most likely the jet’s tail control failed.

Russia’s United Aircraft Corporation reported on December 24 that a Su-57 fighter aircraft had crashed during a test flight in Komsomolsk-on-Amur 111 km from the home airfield. The aircraft’s emergency system responded in the normal mode and the pilot ejected to safety. A special commission will establish the causes of the crash, the corporation said.

A source in military medical circles told TASS that the doctors had examined the pilot and found no injuries. He has been discharged from hospital.

This is the first crash of Russia’s fifth-generation Su-57 fighter jet.