Aeroflot Flight 5143

The Tu-154B-2 registration CCCP-85311 was manufactured at the Aviakor Plant on November 30, 1978.{{Cite web |title=Soviet Database |url=https://www.scramble.nl/database/soviet/details/181_68970 |access-date=2025-02-02 |website=www.scramble.nl}} On January 2, 1979, the aircraft was transferred to the Ministry of Civil Aviation, which was given to the Tashkent Aviation Unit 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.

The Tu-154 (CCCP-85311) was operating the first leg of the flight from Karshi to 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 adults and 52 children, which met the standard regulations of {{convert|92.2|tonnes|lb}}. The aircraft took off at 23:00 PM, 4 hours behind the scheduled departure of 19:00; the temperature of Karshi Airport was {{convert|33|C|1}}. The Tu-154 climbed altitude, following the guidelines of the Aircraft Flight Manual (AFM).{{Cn|date=January 2025}}

The aircraft gained an altitude of {{convert|11,600|m|-3}} at a speed of {{convert|400|kph|kn|abbr=on}}. The crew had changed the autopilot to gain speed, leading 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 {{convert|86.5|tonnes|lb}}; the air temperature of the specified flight path was {{convert|16.5|C-change|round=0.5}} higher than the standard. The Tu-154 suddenly entered a critical angle of attack. This led to disruption in the airflow to the engines, leading to shaking; the flight engineer thought it was a compressor stall and ordered the crew to decrease the speed.{{Cn|date=January 2025}}

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 angles of attack; as a result, the engines failed, causing the aircraft’s speed to decrease {{convert|290|kph|kn|abbr=on}} after 1 minute and 17 seconds after the repeated angles of attack, leading the aircraft to lose control and enter a flat spin.{{Cn|date=January 2025}}

The crew contacted the dispatcher, stating that they were in a flat spin and had no power on the engines.{{Cn|date=January 2025}}

The aircraft remained in the spin for 2 minutes and 33 seconds, and at 23:46, it impacted the ground in a remote part of the Uchkuduk District, roughly {{convert|30|km|-1}} east of the small town of Kokpatas and {{convert|70|km|-1}} northeast of Uchkuduk itself. All 200 occupants were killed.{{Cn|date=January 2025}}

CCCP-85311's cockpit voice recorder was discovered to be damaged by the impact. The Ministry of Civil Aviation had concluded the cause of the accident:{{cite book |last1=Gero |first1=David |title=Aviation Disasters Second Edition |publisher=Patrick Stephens Limited |year=1996 |page=187}}

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.

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 fail to be aware of the situation. This is unconfirmed, as the investigation materials made by the Ministry of Civil Aviation are classified and not published.{{Cn|date=January 2025}}

• Vasily Vasilyevich Ershov mentioned the accident in a chapter in his book, Reflections of a Sled Dog.{{Cite book |last=Ershov |first=Vasily Vasilyevich |title=Раздумья ездового пса |isbn=9785699955077 |language=ru |trans-title=Reflections of a sled dog}}
• The accident was mentioned in Vladimir Chemguevich Mezokh's book, Features of Behaviour and Piloting of Main Passenger Aircraft in Critical Flight Modes.{{Cite web |date=2007-08-16 |title=Особенности поведения и пилотирования магистральных пассажирских самолетов на критических режимах полета - МФАБ |trans-title=Peculiarities of behavior and piloting of mainline passenger aircraft in critical flight modes - MFAB |url=http://www.fsfi.avia.ru/reviews/review23.shtml |archive-url=https://web.archive.org/web/20070816225348/http://www.fsfi.avia.ru/reviews/review23.shtml |archive-date=16 August 2007 |access-date=2024-12-23 |language=ru}}

{{Portal|Aviation|Soviet Union|Uzbekistan|1980s}}

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{{Reflist}}

• [https://asn.flightsafety.org/asndb/327165 Accident description] at the Aviation Safety Network
• [https://airdisaster.ru/database.php?id=71 Detailed description at airdisaster.ru]

{{Aeroflot}}

{{Aviation incidents and accidents in 1985}}

{{Aviation accidents and incidents in the Soviet Union in the 1980s and 1990s}}

{{Aviation accidents and incidents in Uzbekistan}}

Category:Aviation accidents and incidents in 1985

Category:Airliner accidents and incidents caused by pilot error

Category:Aviation accidents and incidents in the Soviet Union

Category:Aviation accidents and incidents in Uzbekistan

5143

Category:Accidents and incidents involving the Tupolev Tu-154

Category:1985 in the Soviet Union

Category:July 1985 in the Soviet Union

Category:Airliner accidents and incidents caused by stalls

Category:1985 disasters in the Soviet Union