In 1994 an Airbus 304-310 took a standard route flight from Moscow to Hong Kong. The plane was in perfect technical condition and had more than 5000 airframe hours.
When the plane reached the Novokuznetsk reporting point his daughter enter the cockpit and asked to sit on the left-sided (co-pilot) seat. He allowed her and demonstrated some autopilot features (which were quite new at that time). He demonstrated submodes like HDG/S and NAV which alter the heading. The daughter was really amazed by her fathers skills.
A little later his son enter the cockpit and asked to sit on his spot (the right-sided seat). Even though the pilot knew it’s against regulations he allowed his son to take a quick seat, but the little boy was not happy only with sitting there. He wanted to pretend he is in control of the whole aircraft and asked to turn the control wheel. The pilot wanted to demonstrate the same features (to his son and allowed him to turn the wheel just a little bit.
The little kid turned the wheel very gently with force no more than 8-10kg and held it like that for a few seconds. After that he returned it to neutral position. After a little while the pilot tried to fix the route with the autopilot, but turning the wheel resulted in conflict with the system and it was stuck at neutral position. Then the plane started to bank to the right with 2.5 degrees per second even though the autopilot remained active. In 90 seconds the plane reached 45 degrees and the autopilot was unable to maintain the altitude.
This caught the attention of the pilot and co-pilot and they realized they need to regain their seats. Regaining the seats took them like 2-3 seconds, but unfortunately it was too late. The plane kept banking to the right until reaching 90 degrees which caused it to enter in a spin and 2 minutes and 6 seconds later hit the ground resulting the death of all 75 people on board.
Read the full report here.