Overview
A seaplane carrying one passenger and five crew members was completing a post-maintenance test flight when it crashed while attempting to land in the Khimki Reservoir. Two crew members were killed, three others were injured, and the passenger was unhurt. The aircraft sank and was lost.
Accident Sequence
The crew attempted to land on the reservoir located northwest of Moscow. During the landing approach, the aircraft struck the water surface, nosed down, and overturned. The accident occurred on a calm water surface that exhibited a glassy or mirror effect due to the position of the sun.
Investigation Findings
The official investigation determined that the pilot in command selected an incorrect approach configuration. The approach speed was set at 220 km/h instead of the prescribed 170 km/h. Additionally, the aircraft was flown in a slight nose-down attitude during the approach. The combination of excessive speed and improper pitch attitude, along with the glassy water conditions, led to the aircraft overturning upon contacting the water.
Probable Cause
The accident was the result of a wrong approach configuration on the part of the pilot in command, specifically an approach speed of 220 km/h versus the prescribed 170 km/h and a slight nose-down attitude, which caused the aircraft to overturn while contacting the glassy water surface.