Aeroflot Flight 5143

Aeroflot Flight 5143 was a scheduled domestic passenger flight between the Soviet cities of Karshi and Leningrad with a stopover in Ufa, operated by the Uzbek division of Aeroflot. On July 10, 1985, the Tupolev Tu-154 operating the flight crashed due to a high-altitude stall in the Kyzylkum Desert, near the city of Uchquduq. The crash resulted in the deaths of all 200 occupants onboard the flight, making it the deadliest accident in the Soviet Union and Uzbekistan, and the deadliest crash of a Tu-154.

Accident

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 92.2 tonnes. The aircraft took off at 23:00 PM, 4 hours behind the scheduled departure of 19:00; the temperature of Karshi Airport was 33 C. The Tu-154 climbed altitude, following the guidelines of the Aircraft Flight Manual (AFM).

The aircraft gained an altitude of 11,600 m at a speed of 400 kph. 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 86.5 tonnes; the air temperature of the specified flight path was 16.5 C-change 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.

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 290 kph after 1 minute and 17 seconds after the repeated angles of attack, leading 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 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 30 km east of the small town of Kokpatas and 70 km northeast of Uchkuduk itself. All 200 occupants were killed.