What happened
During a night cruise at 1-0,100 meters near the Novokuznetsk reporting point, the flight crew allowed two passengers, the children of the captain, to enter the cockpit. While the captain was demonstrating autopilot heading and navigation submodes, the captain's son occupied the left-hand seat and applied a small amount of force to the control wheel. Although the wheel was returned to a neutral position, it remained physically blocked.
As the captain attempted to use the navigation submode to return the aircraft to its original course, the autopilot's attempt to level the aircraft conflicted with the blocked control wheel. The resulting tension on the wheel increased until the torque limiter activated, disconnecting the autopilot servo from the aileron linkage, though the autopilot remained engaged. This caused the Airbus A310 to begin a right-hand bank at a rate of 2.5 degrees per second.
As the bank angle reached 45 degrees, the aircraft struggled to maintain altitude and began buffeting. The captain instructed the co-pilot to take control; however, because the co-pilot's seat was positioned fully aft, it took several seconds for him to reach the controls. The aircraft continued to bank until it reached 90 degrees, followed by a steep pitch-up with accelerations of +4.8g. The aircraft subsequently stalled and entered a spin, striking the ground two minutes and six seconds later. The impact caused the aircraft to disintegrate, resulting in 75 fatalities, including 25 foreign passengers.
Findings
- The primary cause was the conflict between autopilot commands and the manually blocked control wheel.
- The physical obstruction of the control wheel prevented the autopilot from maintaining the programmed flight path.
- Delayed crew response due to the co-pilot's seat position hindered the recovery attempt.