Vortices

Airtourer and CT-4 aircraft generate significant wingtip vortices, even in 1 'g' flight. They have little to no effect on an aircraft in echelon (unless it's too close). However, in line astern the vortices will roll an aircraft that is not immediately behind the leader. Unless positive action is taken to prevent this roll, the aircraft will change heading and fly through line astern into the opposite vortex. The process repeats itself, and ultimately the aircraft is 'spat' out of formation. Your aim is to stay in position, so be positive with the aircraft without overcontrolling.