What defines windshear?

Windshear is defined specifically as a change in wind speed and/or direction over a short distance along the flight path. This definition is crucial because windshear phenomena can significantly affect aircraft performance, particularly during takeoff and landing phases of flight. A sudden change in either the speed or direction of the wind can lead to unexpected shifts in lift or drag, which may impact an aircraft’s stability and control.

The other options describe different meteorological concepts but do not accurately capture the essence of windshear. Continuous changes in wind speed over large distances relate more to broader atmospheric dynamics, while sudden drops in temperature and unexpected altitude increases pertain to different flight conditions or emergencies. Understanding windshear and its implications on aircraft operations is vital for pilots to ensure safety during critical stages of flight.