Aeroflot Flight 6551

Conclusions

Two local military units questioned by investigators reported that they had not fired any projectiles into the air around the time of the crash nor were there any air force aircraft in operation that could have collided with the flight. Investigators felt that the first altitude and speed of the 20–30 seconds of reduced altitude correlated with a controlled emergency reduction in altitude, followed by an unexplainable loss of control that led to an overspeed situation. Investigators thought that one of the reasons possible would have been a crew member unintentionally losing control of an elevator during an emergency descent, but it could not be conclusively confirmed. At the time of the rapid decline that led up to the accident, the propellers were feathered, but it is unknown if the crew had done so or if the autopilot had done so.

Two round puncture holes in the fuselage of the rear luggage compartment; investigators had the portion of the compartment recovered and sent for analysis to see if an artillery shell could have caused the damage, but analysis concluded that the holes resulted from the crash itself with a lack of explosive residues present. Despite the recovery of the flight data recorders and most of the wreckage, the commission was not able to pinpoint an exact cause of the crash, in part due to the amount of damage sustained by the flight data recorders limiting the amount of information that could be recovered.