Description of the accident

The aircraft was covering the second leg of the flight, cruising at an altitude of 11,600 metres (38,100 ft) with an airspeed of only 400 kilometres per hour (250 mph), close to stalling speed for that altitude. The low speed caused vibrations which the aircrew incorrectly assumed were engine surges. Using the thrust levers to reduce engine power to flight idle, the crew caused a further drop in airspeed to 290 km/h (180 mph). The aircraft stalled and entered a flat spin, crashing into the ground near Uchkuduk, Uzbekistan, at that time in the Soviet Union. There were no survivors among the 191 passengers and the 9 crewmen.

It is the deadliest air disaster in Soviet and Uzbek aviation history, and as of February 2012 has the highest worldwide death toll of any accident involving a Tupolev Tu-154.

Cause

Flight 7425's cockpit voice recorder was destroyed in the crash. Investigators with the help of psychologists studied the human factors that led to the aviation incident. Their findings were that Flight 7425's flight crew were very fatigued at the time of the crash due to their having to spend 24 hours at the departure airport prior to takeoff. Another factor in the crash was inadequate regulations for crews encountering abnormal conditions.