On April 17, 2021, at approximately 10:00, a Mi-2 helicopter, registration RA-20977, was performing aerial chemical spraying operations in the Seversky District, Krasnodar Krai. The aircraft was being operated by OOO "MAL-AVIA" to treat winter crops with herbicide.
Prior to the flight, the aircraft was refueled with 180 liters of TS-1 grade kerosene. The pilot did not undergo a formal medical examination at the landing site, as regulations allow the pilot-in-command to make the decision for flight authorization when no medical personnel are present at the landing site. The pilot reported no health concerns, and pre-flight maintenance had been completed by a qualified technician.
During the flight, one blade of the tail rotor detached from the aircraft. This separation caused significant damage to the tail gearbox, including damage to the end beam, the cardan eye of the drive shaft, and deformation of the splined tip of the tail shaft.
The accident resulted in one fatality. Investigations into the aircraft's maintenance history indicated that the tail rotor hub components showed signs of prolonged storage in high-humidity conditions, alongside a failure to follow a regular lubricant replacement schedule.