Part 1 of Essay
1. The complicated task of piloting an aircraft can be broken into two broad categories. The first is keeping the aircraft flying. The second is arriving at a given destination. The second is always being effected by the first. Unlike a car, small deviation in course can over great distances cause the aircraft to arrive ....

Part 2 of Essay
.... such as rate of flow of texture outward from or convergence of parallel linear features to visually fly the aircraft. Estimates of speed are derived from global optic flow (GOL). This is the rate that texture flows over the optical area. This can be effected by elevation, at higher elevations underestimation of true speed will occur. Approach path distortions occur when there is a slope before the landing strip or other visual features such as dwarfed trees. The human eye is not designed for conditions found ....