Flight instructors need to recognize a stall/spin situation, teach their students how to avoid them, and recover from a spin if their student gets them into that situation. In a stall, the angle of attack between the wing and the relative wind becomes too great, and the airflow over the wings separates. A spin happens when one wing stalls more than the other, causing the airplane to rotate and spiral downwards. In the video, the high pitched sound is the stall horn, warning that a stall is about to occur.
