Aeroflot Flight 5143

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Aeroflot Flight 5143

Wreckage of CCCP-85311
Accident
Date	10 July 1985
Summary	Crashed after high-altitude stall
Site	Uchkuduk, Uzbek SSR, Soviet Union 42°9′24″N 63°33′20″E / 42.15667°N 63.55556°E / 42.15667; 63.55556
Aircraft
An Aeroflot Tu-154B-2, similar to the accident aircraft
Aircraft type	Tupolev Tu-154B-2
Operator	Aeroflot
Registration	CCCP-85311
Flight origin	Karshi Airport, USSR
Stopover	Ufa Airport, USSR
Destination	Pulkovo Airport, USSR
Occupants	200
Passengers	191
Crew	9
Fatalities	200
Survivors	0

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.^[1]

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.^[1]

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 in modern day Russia. ^[2]

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 on board.^[2]

The aircraft was operating the first leg of the flight, and cruising at 11,600 metres (38,100 ft) with an airspeed of 400 km/h (220 kn; 250 mph), close to stalling speed for that altitude. The low speed caused vibrations, which the aircrew incorrectly assumed were compressor stalls. Using the thrust levers to reduce engine power to flight idle, the crew caused a further drop in airspeed to 290 km/h (160 kn; 180 mph). The aircraft stalled and entered a flat spin, slamming into the ground near Uchkuduk, Uzbekistan, at that time in the Soviet Union. There were no survivors.^[1]

Flight 5143's cockpit voice recorder was destroyed in the crash. Investigators, with the help of psychologists, found out that several factors were responsible for the crash.

The aircraft , a Tupolev Tu-154 could carry a maximum of 180 passengers. But on that fateful night, it was carrying 200 passengers ; and the total weight onboard was 96% of the MTOW. Also ; on that fateful night ; the air temperature was 16°C higher than normal which adversely affected the flight performance. (Note that the MTOW was calculated without accounting the air temperature). Due to these factors , the airspeed at cruising altitude was dangerously close to stall speeds.

Furthermore ; the crew was extremely tired. They were based at Tashkent ; which meant that they had to fly to Karshi airport as passengers on a different flight (which was operated by the same aircraft involved in the crash). The flight was scheduled at 6 AM and had everything gone according to plan ; the crew would have had sufficient rest before flying. But that day ; there was a severe sandstorm ; which delayed the flight. They arrived at Karshi at 6 PM ; and due to technical problems ; the Tu-154 could not be prepared to fly before 11 PM. The crew could have rested ; but there simply were no rest facility available at Karshi airport. By this point ; the crew had been awake for more than 20 hours and by the time they took off ; they were at their breaking point. Right after take-off the pilots set a high rate of ascent and experienced pilot fatigue ; due to which they failed to monitor their instruments. The high rate of ascent caused a high angle of attack ; slowing down the plane to near stall speeds and causing it to shake mildly. The shaking woke them up all of a sudden ; but they misjudged the situation as a compressor stall ; stalling the plane even more by reducing the throttles. Their desicion making ablities and reaction speed were affected due to fatigue - they made erratic and slow control inputs ; causing the plane to enter a flat spin from which they could never recover.

Also it is to be noted that the pilots did not receive proper training ; nor did the aircraft involved had equippment ; in order to recover from a flat spin.

• Aeroflot accidents and incidents
• Aeroflot accidents and incidents in the 1980s