The Il-14 passenger plane operated on a regular flight from Bourgas Airport (BOJ) to Sofia (SOF), Bulgaria. There are four crew members and 31 passengers on board. Weather at Sofia was worsening and while taxiing for takeoff the crew received information that the visibility at Sofia was 1500 m, which was below minima. The flight departs at 19:01. En route it appeared that there was no improvement of the visibility at Sofia. The captain decided to divert to Plovdiv. Radio contact with the controller at Plovdiv was established at 19:50. Four minutes later, the civilian controller was relieved of duty by a military controller. The military controller issued descent instructions without being positively aware of the position of the aircraft. The airplane was vectored for a visual approach and descended until it flew into the side of a hill near Cruncha. All aboard were killed. The crew elected to divert to Plovdiv due to thick fog at the destination Sofia. On approach, the aircraft struck a mountain in the Rila Mountain range.