Accident
On a local test flight departing from Moscow-Sheremetievo Airport, the aircraft experienced a failure of engine number two a few minutes after takeoff. The propeller could not be feathered, resulting in increased drag. The aircraft subsequently lost altitude and speed. The crew decided to return to Sheremetievo Airport for an emergency landing, but during the final approach, the airplane stalled and crashed in flames approximately 4 kilometers short of the runway threshold. The aircraft was destroyed, and all ten occupants—five engineers and five test pilots—were killed.
Aircraft and Crew
The test flight was conducted on behalf of AKDON – Aviatsionnaya Krasnoznamyonnaya Diviziya Osobogo Naznacheniya, a division of the Soviet Army. The aircraft was equipped with four Kuznetsov NK-4 engines. No further details about the aircraft type, registration, or the crew were provided in the investigation report.
Probable Cause
The official investigation determined that the aircraft's four Kuznetsov NK-4 engines were not fitted with a propeller feathering system. When engine number two failed, the inability to feather the propeller caused high drag, leading to a loss of speed and eventual stall.