Initially, the aircraft was registered under the tail number CCCP-Л1358 and was transferred to the Main Directorate of the Civil Air Fleet under the Council of Ministers of the USSR, which assigned it to the 185th (Magadan) Aviation Detachment of the Far Eastern Territorial Administration of the Civil Air Fleet.

At that time, due to adverse weather conditions, the Nikolayevsk-on-Amur Airport was closed, so the aircraft had to fly over it without landing.

According to the weather forecast provided to the crew, the route from Okhotsk to Khabarovsk was expected to have continuous mid-level cloud cover, with stratiform and ragged clouds with bases at 200-300 meters above the Okhotsk airfield level, where icing, precipitation, and visibility of 2-4 kilometers were observed.

In Khabarovsk itself, variable (6-9 octas) stratocumulus cloud cover with a base of 300-600 meters, rain, visibility over 10 kilometers, and a west wind of 5-8 m/s were forecasted.

At 13:16, while cruising at 2,700 meters with a ground speed of 350 km/h, the crew reported passing Nizhnetambovskoye, adding that they were not receiving signals from the NDBs.

At 14:14, they transmitted: "According to calculations, passed Yelabuga [ru], 2,700 meters in clouds, the compass is not working, permission to descend and guide by radar requested."

After passing Troitskoye, the district service dispatcher handed off the aircraft to the area control center (ACC).

The radio operator of CCCP-Л3904 spent a long time unsuccessfully trying to contact the ACC via VHF, while simultaneously establishing communication with the short-wave direction finder at Khabarovsk airport, from which he received a bearing: "approximately 312°".

The district service dispatcher did not know the exact location of the aircraft but nevertheless instructed them to descend to 1,800 meters and request a bearing from the military via VHF.

Five minutes later, at 15:41, the crew reported: "Remaining fuel 450 liters, ground speed 200 km/h, altitude 3,300 meters in clouds."

At 15:57, they reported a remaining fuel of 210 liters, indicating that they should prepare for a forced landing by selecting a suitable area.

Meanwhile, unaware of this, the crew, in an attempt to prevent drift, effectively began to move the aircraft west of the route.

Although the dispatchers had functional and operational radio equipment, they did not use it for monitoring and managing flights, leading aircraft to follow routes to Khabarovsk 30-40 kilometers left of the course.

[2] When the aircraft did not land in Khabarovsk at the scheduled time of 14:15, the dispatching service did not raise any concerns and only noticed it 15 minutes later.

From 14:16 to 15:19, when attempts were made to obtain bearings from the short-wave direction finder, the Il-12 effectively began to circle in one area.

Only at 15:20 was the actual location of CCCP-Л3904 determined, but by then, it was too late, as the remaining fuel supply, considering the strong headwind from the north, did not allow them to reach Khabarovsk.

Not knowing the exact location of the aircraft, the dispatchers, in violation of instructions, began to descend it over a mountainous area.