The aircraft leveled at a cruising altitude of 7,800 metres (25,600 ft) after takeoff until they were instructed by the Almaty Airport region controller at 00:56 MSK to increase altitude to a flight level of 9,000 metres (30,000 ft) and fly on a bearing of 43 degrees; the flight crew confirmed receiving the instruction and proceeded to ascend as directed.

The Semipalatinsk controller attempted to make contact with the plane when it was due to be overhead at 01:52 MSK (04:52 local time) but received no response from the flight.

At the time the weather consisted of clouds at altitudes of 1,000–1,300 metres (3,300–4,300 ft), mild wind and rain, with visibility at 10 kilometres (6.2 mi; 5.4 nmi).

[4] At the time the Il-18 was flying on autopilot when within the span of six seconds the instrument speed decreased from 400 to 370 km/h (220 to 200 kn; 250 to 230 mph) while at its assigned altitude before entering a rapid decline with no lateral roll, reaching overloads ranging from 1.5 to -0.8g.

Investigators thought that one of the reasons possible would have been a crew member unintentionally losing control of an elevator during an emergency descent, but it could not be conclusively confirmed.