On October 27, 2024, an Antonov An-2, registered as RA-33623, was involved in an event on the northwestern outskirts of Essentuki, in the Stavropol region of the Russian Federation. The aircraft was operated by OOO "AVIAKHIM YUGTOST 26".
Laboratory analysis conducted by FAA "Aviareestr Rossii" examined fuel samples taken from both the aircraft's fuel tank and a separate fuel tank. The testing identified the fuel as AI-95 automotive gasoline. While the physicochemical parameters generally met GOST 32513-2913 standards, the samples contained mechanical impurities at levels of 0.7 g/t and 0.5 g/t, respectively. These impurities were primarily environmental pollutants.
Differences were noted in the fractional composition of the fuel found in the aircraft's tank, specifically regarding the volume of evaporated gasoline. This variation may have resulted from the evaporation of light fractions during flight or issues related to the sampling and storage process.
As part of the investigation, engine components from the ASH-62IR engine, including two BSM-9F magnetos, 18 SD-48BSM spark plugs, an R-9SM2 constant speed regulator, and an AKM-62IRA carburetor, were submitted for performance testing.