Flight Operations
On May 3, 2017, a Robinson R-44 helicopter, registration RA-04156, operated by ZAO Avikompaniya 'Lite Air', performed aerial patrol flights north of Beloretsk under a contract with GBU 'Center for Prevention and Suppression of Forest Fires RB' (agreement No. 0101200009517000128_222237 dated April 5, 2017). The flight crew had two representatives of the customer on board, picked up at Zubovo (a suburb of Ufa) after the pilot flew from Ufa airport to the Beloretsk area.
Following the patrol, the pilot-in-command (PIC) landed the helicopter at Beloretsk at 15:45. The PIC planned to continue patrol flights on May 4 and informed the Deputy Director for Flight Operations (ZGD po OLR) of ZAO Avikompaniya 'Lite Air' about this, requesting refueling. According to an explanatory note from the Deputy Director dated May 12, 2017, the PIC called at 15:45 UTC, stating that returning to Ufa airport was not possible due to darkness, and that flights would continue the next day with the customer; he also requested refueling.
Refueling and Witnesses
At approximately 18:30, the PIC fully refueled the helicopter from a barrel brought by a worker of ZAO Avikompaniya 'Lite Air'. The PIC then departed for rest.
Witness 1 (explanatory note dated May 10, 2017) stated that he began guard duty for the Robinson helicopter at Beloretsk airport at about 21:30 local time on May 3, 2017. Around 23:30 local time, pilots arrived and refueled the helicopter.
Witness 2 (explanatory note dated May 11, 2017) stated that upon arriving at 23:20 local time, he called the PIC, who told him to come to the airport.
No further events are recorded in the provided source material.