An actuator is arranged to move an aircraft component such as a landing gear leg, flap or aileron between a first position and a second position, net load from external forces acting on the aircraft component tending to drive it towards the first position. One method involves determining a brightness value of at least one pixel of each bi-directionally predicted intermediate frame in the sequence as an equal average of brightness values of pixels in non-bidirectionally predicted frames bracketing the sequence of bi-directionally predicted intermediate frames. A hydraulic cylinder is coupled to the linkage assembly for urging the linkage assembly downwardly toward the soil. The third portion of the electronic document is located between the edge and a position indicating point.