What happened
A local training mission originated from Ulan-Ude-Mukhino Airport. During the course of several circuit patterns, the crew initiated a procedure to simulate an engine failure by shutting down one of the engines. After the propeller had been successfully feathered, the flight engineer inadvertently shut down the remaining operational engine.
Unable to maintain flight on a single engine following the error, the aircraft performed a belly landing on Bodorodski Island, situated approximately 8 km before reaching runway 26. Following the impact, a fire broke out and partially destroyed the airframe. There were no fatalities among the crew, though all members sustained slight injuries during the incident.
Findings
The investigation determined that the accident was caused by the unintentional shutdown of the second engine by the flight engineer while performing a single-engine simulation exercise.