Incident Overview
The accident occurred during a night flight conducted on behalf of the Soviet Ministry of Naval Construction (MSP). The crew was cruising when the pilot notified air traffic control that the artificial horizon had failed.
Loss of Control and Descent
Shortly after the pilot's report, the aircraft went out of control and entered a steep dive. The descent subjected the airframe to aerodynamic forces beyond its structural limits, causing partial disintegration while still airborne.
Crash Site and Fatalities
The aircraft came down in a pasture, where it was completely destroyed. All seven individuals aboard the aircraft were killed in the impact.
Investigation Findings
Investigators determined that the accident sequence began with an unexplained failure of the artificial horizon. This loss of attitude reference led to a loss of control, and the subsequent high-speed dive resulted in an in-flight breakup due to aerodynamic loads that surpassed the aircraft's design and certification specifications.