What happened
A local test flight, conducted on behalf of the AKDON – Aviatsionnaya Krasnoznamyonnaya Diviziya Osobogo Naznacheniya (a division of the Soviet Army), ended in a fatal accident near Moscow-Sheremetievo Airport. The aircraft was carrying ten occupants, consisting of five test pilots and five engineers.
Shortly after departing from the airport, the crew experienced a failure of the number two engine. During the subsequent attempt to return to Sheremetievo Airport for an emergency landing, the aircraft lost both altitude and airspeed. As the plane approached the runway threshold, it entered a stall and crashed approximately 4 km short of the runway, resulting in a post-impact fire. The impact resulted in ten fatalities and the total destruction of the aircraft type.
Findings
The investigation determined that the aircraft was powered by four Kuznetsov NK-4 engines. A critical factor in the accident was that these engines were not equipped with a propeller feathering system. Following the failure of the second engine, the crew was unable to feather the propeller, which generated excessive aerodynamic drag. This increased drag led to the loss of airspeed and the eventual stall during the final approach.