The illustration shows aircraft flying on three courses and then determining its drift on these three headings. In the double drift method, aircraft flies on two headings and calculates its drift on those two headings. By drawing the courses and tracks, wind velocity can be calculated. A computer can be used instead of drawing the courses and tracks as shown in the illustration.
A method of determining wind velocity by observing the drift on two or three headings. An aircraft is flown on two or three headings, and the drift on these headings is noted. Then these are plotted and the wind velocity is determined. Wind velocity also may be found by using a computer to implement this same method.