Aeroflot Flight 5143

Not to be confused with Aeroflot Flight 513.

Aeroflot Flight 5143

Wreckage of CCCP-85311
Accident
Date	July 10, 1985 (1985-07-10)
Summary	Crashed after high-altitude stall
Site	Kyzylkum Desert, near Uchkuduk, Uzbek SSR, Soviet Union 42°9′24″N 63°33′20″E
Aircraft
Aircraft type	Tupolev Tu-154B-2
Operator	Aeroflot
Call sign	311
Registration	CCCP-85311
Flight origin	Karshi Airport, Karshi
Stopover	Ufa Airport, Ufa
Destination	Pulkovo Airport, Leningrad
Occupants	200
Passengers	191
Crew	9
Fatalities	200
Survivors	0

Aeroflot Flight 5143, a scheduled Tupolev Tu-154 passenger flight, was involved in an aviation accident on July 10, 1985, when it crashed due to a high attitude stall in the Kyzylkum Desert, near the city of Uchkuduk, which had resulted in the deaths of all of the 200 occupants onboard the flight; making it the deadliest accident in the Soviet Union and Uzbekistan, and the deadliest crash of Aeroflot’s Tu-154s in service.

Aircraft

An Aeroflot Tu-154B-2, similar to the accident aircraft

The Tu-154B-2, registration CCCP-85311 (MSN 78A311- Serial number 03-11), was manufactured at the Aviakor Plant on November 30, 1978. On January 2, 1979, the aircraft was transferred to the Ministry of Civil Aviation, which was given to the Tashkent Aviation Department of the Uzbek Civil Aviation Directorate. It was powered by three Kuznetsov NK-8U turbofan engines. At the time of the accident, the aircraft accumulated 12,443 flight hours and 5,660 flight cycles.

Accident

The Tu-154 (CCCP-85311) was operating the first leg of flight 5143 from Karshi to Leningrad, with a scheduled stopover at Ufa, piloted by the crew of the 219th flight squadron, consisting of commander O. P. Belisov (48), co-pilot A. T. Pozyumsky (48), flight engineer A. S. Mansurov (32), navigator G. N. Argeev (41), with 5 flight attendants onboard the flight. There were 191 passengers onboard the flight, which had consisted of 139 and 52 children, which met the standard regulations of 92,200 kg (92.2 tonnes). The aircraft took off at 23:00 PM (4 hours behind scheduled departure of 19:00 PM), the temperature of Karshi Airport was 33°C (91.4°F). The Tu-154 climbed altitude, following the guidelines of the Aircraft flight manual (AFM).

The aircraft gained altitude of 11,600 meters (38,000 ft) at a speed of 400 km/h (215 kts), the crew had changed the autopilot to gain speed, leading for the aircraft to pitch down, the crew pulled the aircraft up, making the Tu-154 on the verge of activating the alarm of the critical angle of attack, suddenly, the alarm had stopped due to a blown fuse. The aircraft then entered the jet flow zone with a weight of 86,500 kg (86.5 tonnes), the air temperature of the specified flight path was 16.5°C (61.7°F) higher than the standard. The Tu-154 suddenly entered a critical angle of attack. This led to disruption in the air flow to the engines, leading to shaking, the flight engineer thought it was a compressor stall, and ordered for the crew to decrease the speed.

Instead of pushing back the throttle, they both decreased and increased the speed of the aircraft. The captain still continued to hold the altitude. The aircraft had then repeatedly had critical angle of attacks, as a result, the engines failed, causing the aircraft’s speed to decrease 290 km/h (160 kts) after 1 minute and 17 seconds after the repeated angle of attacks, leading for the aircraft to lose control and enter a flat spin.

The crew contacted the dispatcher, stating that they were in a flat spin and had no power on the engines.

The aircraft entered was in the spin for 2 minutes and 33 seconds, and at 23:46 PM, impacted the ground of the Kyzylkum desert near Kokpatas, 68 km away from Uchkuduk, which all of the 200 occupants were killed.

Investigation

Official conclusions

CCCP-85311’s cockpit voice recorder was discovered to be damaged by the impact. Specialists and the Ministry of Defense had concluded the cause of the accident:

The cause of the disaster was the aircraft entering a flat spin at cruising altitude with a high flight mass, influenced by a high non-standard outside air temperature, a small angle of attack margin, and engine thrust. Under these flight conditions and the rapidly developing catastrophic situation, the crew made a number of deviations from the requirements of the Flight Operations Manual, lost speed, and was unable to control the aircraft.

Theories

It is believed that the crew had been exhausted due to the poor resting conditions during the delay at Karshi, which caused the pilots to make inadequate decisions during the ascent and failed to be aware about the situation. This is unconfirmed as the investigation materials made by the Ministry of Civil Aviation are classified and not published, which makes it unconfirmed.

In popular culture

• Vasily Vasilyevich Ershov, mentioned the accident in a chapter in his book, Reflections of a sled dog.
• The accident was mentioned in Vladimir Chemguevich Mezokh’s book, Features of behavior and piloting of main passenger aircraft in critical flight modes.

See also

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