On June 30, 2021, a HARMONY LSA with registration RA-2086G arrived at Myačkovo airfield to perform test flights following its recommissioning. The flight was intended to conduct testing around specific geographical areas. The pilot, accompanied by one passenger, performed pre-flight preparations, which included verifying that the takeoff weight of approximately 525 kg was within the 600 kg limit and ensuring the center of gravity was within the 13–33% MAC range.
The aircraft was fueled with approximately 50 liters of AI-95 gasoline. Meteorological conditions were reported as visual meteorological conditions (VMC), and the pilot operated under Visual Flight Rules (VFR). In accordance with Federal Aviation Regulation 128, the pilot assumed responsibility for the flight decision in the absence of medical personnel at the airfield.
At 12:05, the pilot took off and successfully completed four circuits. Subsequent investigations into the aircraft's systems, including the analysis of the oil filter and lubrication oil, found that the Mobil 1 0W-40 oil showed signs of intense oxidation but no large metal particles. The deposits found in the oil filter were minimal, weighing only 0.061 g, and consisted primarily of iron, copper, lead, and tin.
There were no injuries or fatalities reported during the operation.