What happened
On July 30, 2020, the pilot arrived at the Tyungur settlement, located on the southern edge of the Tyungur village in the Ust-Koksa district of the Altai Republic. Operating under a flight assignment issued by AltaiAvia, the pilot was tasked with performing aerial work and agricultural spraying missions using an R-66, registration RA-06353. The landing site at Tyungur was frequently used by the operator's pilots as a location selected via aerial reconnaissance.
On August 3, 2020, the pilot submitted a flight plan via the internet to the West Siberian Air Navigation branch for operations scheduled to begin at 00:00 on August 4, 2020. The intended flight profile involved operating in Class G airspace over mountainous terrain under Visual Flight Rules (VFR). Prior to the scheduled flights on August 4, the pilot did not undergo a formal pre-flight medical examination, which was permitted under specific regulations for locations lacking medical personnel.
The investigation
During the investigation, it was noted that the pilot performed a pre-flight inspection of the R-66 and calculated the flight parameters at 23:05 on August 3, 2020. The investigation revealed that the pilot did not request official meteorological information from the Barnaul or Gorno-Altaysk meteorological stations, nor from the official Aviamettelecom website. Instead, the pilot obtained weather information regarding the Belukha Mountain area via a mobile phone call from a tourism base administrator in the Ak-Kem settlement, located approximately 12 km north of the landing site, at 23:25 on August 3, 2020.