1986 Aeroflot accident near Khanty-Mansiysk

On 17 May 1986 the Aeroflot accident near Khanty-Mansiysk occurred when a Yak-40 was to carry out a test flight; all 5 occupants died.

Course of events

The Yak-40 took off at 15:36 Moscow Time (MSK) / 17:36 local time. Shortly afterwards the pilots requested a climb to 7,800 m, which was not in keeping with the check flight that had been applied for. At 15:48 they reported an altitude of 6,000 m and asked for permission to carry out the task within 5 min. The crew then flew, at that altitude, left turns with a bank of between 25 and 50° and right turns with a 60° bank. During these manoeuvres the acceleration did not exceed 2g and an indicated airspeed of 380–390 km/h (IAS) was maintained. The aircraft, whose engines were running at 91 % thrust, hardly lost any altitude.

At 15:56:56 the Yak-40, slowed to 360 km/h, was gently levelled out horizontally (1.5g). Shortly afterwards, at 15:57:10, a steep right turn was initiated by deflecting the ailerons by 8.5° and the rudder by 8°. Within 8 seconds the aircraft was flying upside down and, with the elevators deflected by 3–5°, it went into a dive in which it descended at up to 100 m/s. On reaching 470 km/h IAS the engines were throttled back to 73 %. At 15:57:31 the aircraft had completed a full barrel roll and the ailerons and rudder had been brought to the neutral position. In the following 3 seconds the dive was ended at 4,500 m. In the meantime a speed of 620 km/h IAS and an acceleration of 5.25g were reached, which was above the Yak-40's operating limits for speed (500 km/h IAS) and acceleration (3.4g). As a result the left wing broke off, which in turn tore off the entire tail. Before impact, parts of the right wing also broke off, including the landing flaps.

The wreck was finally found the next day at 6:00 MSK / 8:00 local time in a riverbed of the Ob.