Aeroflot flight 04 departed Khabarovsk-Novy Airport at 21:45 hours local time on a flight to Moscow’s Vnukovo Airport. The first en route stop was Irkutsk. Weather along the planned route was poor with powerful cumulus clouds. Five minutes after take-off, the crew was instructed to climb to an altitude of 9000 meters. At this altitude the aircraft heading straight towards powerful cumulus clouds. The flight crew obtained permission to climb to 11000 meters in order to overfly the clouds. However, after reaching this altitude, the aircraft was still in clouds. At 22:14 hours the flight was cleared to climb to 12000 meters. After passing 11600 meters the aircraft broke through the top of the clouds. Yet the crew could see powerful cumulus clouds ahead and the captain reported that he would try to get around them, and if he did not succeed, he would return to Khabarovsk. At altitudes of 11,000–12,100 m, there were strong vertical flows in the upper layers of clouds. Taking into account the weight of 66 tons, the aircraft was only able to barely able to maintain their altitude of 12000 meters. Even under the influence of relatively small vertical airflows the aircraft could be sent into critical angles of attack. The aircraft lost speed and entered a descent. Both engines flamed out and the flight crew lost situational awareness in clouds. The aircraft broke up and crashed.