Background
On 30 July 2020, the pilot-in-command (PIC) arrived at the Tjungur landing site, located on the southern outskirts of the village of Tjungur in Ust-Koksinsky District, Altai Republic. The landing site is used by pilots of Altaiavia LLC as a location selected from the air. The PIC was assigned to perform flights in a Robinson R-66 helicopter, registration RA-06353, from Tjungur for aviation work and general aviation under an operational task order dated 29 July 2020, signed by the director of Altaiavia LLC.
Flight Planning
On 3 August 2020, at 23:05, the PIC calculated the flight and conducted a pre-flight inspection of the helicopter. He filed a flight plan via the internet for instrument flight rules (IFR) beginning at 00:00 on 4 August 2020, with the West Siberian Air Navigation center. The flights were planned under visual flight rules (VFR) in Class G airspace over mountainous terrain.
Medical and Weather Information
The PIC did not undergo a pre-flight medical examination on 4 August 2020. This was not contrary to regulations, as the landing site had no medical personnel authorized to conduct such examinations; therefore, the PIC made the decision on crew fitness. He did not request meteorological information from official sources such as AMSG Barnaul, AMSG Gorno-Altaysk, or the Aviamettelecom Roshydromet website. Instead, at 23:25 on 3 August 2020, he obtained actual weather conditions in the area of Mount Belukha via a mobile phone call from the administrator of a tourist base in the village of Ak-Kem, located 12 kilometers north of the accident site.