Flight Planning
On 16 December 2018, the crew of Mi-8T helicopter RA-22649 was assigned a flight plan (No. 2234) to transport personnel of OOO Delovye Linii Sibiri. The planned route consisted of multiple landing sites: Kargassok Prichal, Kedrovy Promzona, 395 Mayskaya, and 572 Mayskaya, with several segments between these points. Scheduled departure was 02:35 local time.
Pre-flight Preparations
The crew arrived at the certified landing site Kargassok Prichal at 01:00. At 01:30, they began pre-flight preparations. Since no medical officer was available at the site, the captain (KVS) authorized the crew for flight per regulations. At 01:40, the second pilot obtained a telephone weather forecast from the AMSG Tomsk station, which did not preclude the flight. The crew boarded the helicopter at 01:50 and reported no issues with its maintenance or condition, as noted in the logbook. Takeoff occurred at 02:35.
Flight Execution
The crew completed six flights during the day. Five of these flights were performed without any remarks. The trajectory of the flights was recorded (Figure 1). After the third flight, at 04:47, the helicopter was refueled with 1,386 kg of TS-1 jet fuel, bringing the total fuel load to 1,786 kg. The fuel was supplied under request No. 082024 and was accompanied by a quality certificate (No. 1115) dated 30 November 2018. Subsequent laboratory tests conducted by OAO Titan confirmed the fuel met specifications (test reports No. 56963, 56964, 5696...).