Incident Overview
A local test flight at Lukhovitsy-Tretyakovo Airport concluded with an accident when the aircraft struck the ground during approach. All six crew members were uninjured, but the aircraft was damaged beyond repair.
Event Sequence
While completing the third turn on approach, the crew activated the feathering system on engine number two. Shortly afterward, at an altitude of 80 to 100 meters, the airplane began to bank left. It lost height and speed, entered a stall, and impacted the ground.
Damage
The impact sheared off the undercarriage. The airplane slid for several dozen yards before coming to rest. The left wing was broken, and the aircraft was damaged beyond repair. No injuries were reported among the six crew members.
Probable Cause
The official investigation determined that the accident resulted from a loss of control on final approach caused by a loss of thrust on engine number one after its propeller went into autorotation, generating negative thrust.