How is 'severe wind shear' defined?

The definition of 'severe wind shear' is centered around the impact it has on aircraft performance, particularly regarding changes in airspeed. A rapid change in wind direction or velocity that results in airspeed changes greater than 15 knots is significant in aviation because such changes can adversely affect an aircraft's stability and control during critical phases of flight, such as takeoff or landing.

This understanding is crucial since wind shear can lead to a dangerous situation where pilots may not have enough time to react to sudden shifts in airflow, potentially resulting in loss of control. Defining it this way helps pilots recognize and prepare for these scenarios, ensuring safety measures can be implemented when such conditions are encountered.

The other definitions provided do not convey the same level of operational impact related to airspeed changes and pilot response, making the selected definition more aligned with aviation safety standards and practices concerning severe wind shear.