Aeroflot Flight 5143

Aeroflot Flight 5143 was a domestic scheduled Karshi–Ufa–Leningrad passenger flight that crashed near Uchkuduk, Uzbek SSR, Soviet Union, on 10 July 1985. The crash killed all 200 occupants (148 adults, including 9 crewmembers, and 52 children) on board. Investigators determined that crew fatigue was a factor in the accident.

Flight 5143 remains the deadliest air disaster in Soviet and Uzbek aviation history, the deadliest in Aeroflot's history, and the deadliest accident involving a Tupolev Tu-154.

Aircraft
Flight 5143 was operated by a Tupolev Tu-154B-2, registration CCCP-85311. It was produced in 1978 at Aviakor, an aircraft factory in Samara.

Crew
Flight 5143 was piloted by 48 year old Oleg Pavlovich Belisov. Throughout his career, Belisov logged 12,283 hours, 3,390 of them on the Tu-154. The co-pilot, 48 year old Anatoly Timofeevich Pozyumsky, logged 12,323 hours, 1629 of them on the Tu-154. The crew also consisted of a navigator, 41 year old Garry Nikolaevich Argeev, and a flight engineer, 32 year old Abduvakhit Sultanovich Mansurov. 5 flight attendants were also onboard.

Accident
The aircraft was operating the first leg of the flight, and cruising at 11600 m with an airspeed of 400 km/h, 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. 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.

Investigation
Flight 5143's cockpit voice recorder was destroyed in the crash. Investigators, with the help of psychologists, studied the human factors that led to the accident. They found Flight 5143's flight crew were very fatigued at the time of the crash from having spent the prior 24 hours at the departure airport prior to takeoff. Another factor was inadequate regulations for crews encountering abnormal conditions.