An Antonov 2 biplane sustained substantial damage when it impacted a church during a forced landing accident at Sanamer, Stavropol Territory, Russia. The aircraft was on a positioning flight from Kevsala (Ipatovo district of the Stavropol region) to Gribnoye, carrying four drums of oil. While flying at low altitude the engine failed. The pilot carried out a forced landing at Sanamer. The aircraft ran over a fence and came to rest against a church. The airplane did not have a valid Certificate of Airworthiness at the time of the accident. Conclusion (translated from Russian): The aircraft accident with the aircraft An-2s/x RA-56528 occurred due to the collision of the aircraft with an obstacle during the forced landing. The necessity of the forced landing was caused by the engine self-absorption during the flight, most probably due to the oil tank bloating and its wall pressing on the engine stop-crane lever on the carburetor. The increase in pressure in the oil tank and its bloating were the result of deposits of soot in the drainage pipe connecting the oil tank with the atmosphere. Contributing factors: – Absence of the tank flushing, including the tank drainage pipeline with the atmosphere provided for by the periodic maintenance after 400ñ30 hours of flight or 12ñ1 month of operation; – Maintenance of aircraft by persons who do not have a certificate of a maintenance and repair specialist; – performance of the flight over the locality at an altitude that does not allow landing outside the locality in case of aircraft malfunction; – performance of the flight by an aircraft under the influence of alcoholic intoxication of the average degree.