On May 28, 2022, an SK-12t5 Orion seaplane, registration RA-1387G, operated by OOO "TNPTs AON," was performing forestry aviation work for forest fire monitoring. The flight plan originally scheduled operations from 07:00 to 15:00, with takeoff and landing occurring at the village of Ishim. After completing the scheduled monitoring tasks, the captain decided to fly the aircraft to Lake Mergen to wash the plane after refueling the tanks with AI-9CO gasoline.
During the flight, the pilot-in-command occupied the left seat while a passenger occupied the right seat. The passenger reported unfastening their seatbelt after the aircraft reached altitude. The aircraft subsequently went down in the waters of Lake Mergen, located in the Ishimsky District of the Tyumen Region.
Following the accident and evacuation from the lake, both the pilot-in-command and the passenger were transported to the Tyumen Region State Healthcare Institution, Regional Hospital No. 4. A forensic medical examination concluded that both individuals sustained moderate injuries. No aircraft design features were found to have contributed to the severity of the injuries.