Aeroflot Flight 5143

Aeroflot Flight 5143
Wreckage of CCCP-85311
Accident
DateJuly 10, 1985 (1985-07-10)
SummaryCrashed after high-altitude stall
SiteKyzylkum Desert, near Uchkuduk, Uzbek SSR, Soviet Union
42°9′24″N 63°33′20″E / 42.15667°N 63.55556°E / 42.15667; 63.55556
Aircraft
Aircraft typeTupolev Tu-154B-2
OperatorAeroflot
Call sign311
RegistrationCCCP-85311
Flight originKarshi Airport, Karshi
StopoverUfa Airport, Ufa
DestinationPulkovo Airport, Leningrad
Occupants200
Passengers191
Crew9
Fatalities200
Survivors0

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.[1]

Aircraft

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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.[2]

Accident

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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).[3]

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.[3]

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.[3]

The crew contacted the dispatcher, stating that they were in a flat spin and had no power on the engines.[3]

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.[3]

Investigation

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Official conclusions

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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:[3][4]

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

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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.[3]

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  • Vasily Vasilyevich Ershov, mentioned the accident in a chapter in his book, Reflections of a sled dog.[5]
  • The accident was mentioned in Vladimir Chemguevich Mezokh’s book, Features of behavior and piloting of main passenger aircraft in critical flight modes.[6]

See also

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References

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  1. ^ Accident description at the Aviation Safety Network. Retrieved on 19 February 2015.
  2. ^ "Карточка самолёта: Туполев · Ту-154Б-2 · СССР-85311 (зав.н. 78A311) ✈ russianplanes.net ✈ наша авиация". russianplanes.net. Retrieved 23 December 2024.
  3. ^ a b c d e f g "Катастрофа Ту-154Б-2 Узбекского УГА в районе пос.Учкудук (борт СССР-85311), 10 июля 1985 года. // AirDisaster.ru - авиационные происшествия, инциденты и авиакатастрофы в СССР и России - факты, история, статистика". airdisaster.ru. Retrieved 23 December 2024.
  4. ^ Gero, David (1996). Aviation Disasters Second Edition. Patrick Stephens Limited. p. 187.
  5. ^ Раздумья ездового пса [Reflections of a sled dog]. ISBN 9785699955077.
  6. ^ "Особенности поведения и пилотирования магистральных пассажирских самолетов на критических режимах полета - МФАБ". 16 August 2007. Archived from the original on 16 August 2007. Retrieved 23 December 2024.