What happened
During a scheduled night training mission departing from Ukurey, the aircraft experienced a series of critical power losses. Approximately two hours into the operation, the first and second engines suffered flameouts. In an attempt to manage the emergency, the crew initiated a diversion toward Chita.
Shortly after this maneuver, roughly 16 minutes later, the third and fourth engines also ceased functioning. Faced with a total loss of propulsion, all seven crew members abandoned the aircraft via parachute. The aircraft subsequently impacted a field in the vicinity of Chita. While six of the crew members were successfully recovered, one crew member died during the bailout process.
Findings
Investigations into the total loss of power across all four engines determined that water contamination within the fuel supply was the primary reason for the sequential engine flameouts.