What happened
During a scheduled cargo operation flying from Kazan toward Kuybyshev, the crew of the aircraft reported a fire located in the middle of the cabin. After notifying air traffic control and declaring an emergency, the flight crew began an emergency descent. During this maneuver, the aircraft suffered a partial structural failure and subsequently crashed into an open field in the vicinity of Bazlarne Mataki.
There were four fatalities among the occupants of the aircraft. No survivors were reported from the crash site.
Findings
Investigations into the incident could not definitively establish the origin of the fire or the specific cause of the accident. While inspections of the electrical wiring, fuel hoses, and fuel delivery systems showed no evidence of malfunction or irregularities, it was determined that aerodynamic forces exceeded the aircraft's structural certification during the descent, leading to the loss of structural integrity.