Roll is when we bank or turn the aircrafts wings. Turning the control yoke right or left will cause the aircraft the bank in the same direction. This is accomplished with the ailerons, hinged surfaces out on the far end of each wing. They are similar in function to the elevator. However they work opposite each other. One goes up while the other goes down. The downward deflected aileron lifts the wing while the upward deflected aileron drops the opposite wing. This simultaneous lifting and dropping causes the aircraft to roll in the direction we desire thus turning the airplane. But this rolling causes another turning force, yaw, which we'll discuss in it's own segment.