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No evidence of a technical malfunction was found. Cockpit voice and flight data recorders revealed the presence of the relief captain's 12-year-old daughter and 16-year-old son in the cockpit. While seated at the controls, the pilot's son had unknowingly partially disengaged the A310's autopilot control of the aircraft's ailerons. The autopilot then disengaged completely, causing the aircraft to roll into a steep bank and a near-vertical dive. Despite managing to level the aircraft, the first officer over-corrected when pulling up, causing the plane to stall and enter into a spin; the pilots managed to level the aircraft off once more, but the plane had descended beyond a safe altitude to initiate a recovery and subsequently crashed into the mountain range. All 75 occupants died on impact.
Wikipedia: https://en.m.wikipedia.org/wiki/Aeroflot_Flight_593
Source: http://www.planecrashinfo.com/