[ddkto]

It appears that the two controls are physically linked, but have a 'fuse' mechanism. When the two pilots apply lower forces to their controls, the forces are transferred between the controls and they 'fight' each other to move the sticks. After a certain threshold (50 lbs?), the two controls move independently.

In all cases, the flight computer works of the average of the two sticks. When they are in sync, this works great. In a situation like this one, where the pilots are pushing in opposite directions, the average will all of a sudden, be quite different from both controls.