How is severe windshear identified?

Severe windshear is identified by significant changes in either airspeed or vertical speed, with criteria set to establish the thresholds for concern. In this case, airspeed changes greater than 15 knots or vertical speed changes exceeding 500 feet per minute are recognized as indicators of severe windshear.

This definition emphasizes the importance of both aspects—airspeed and vertical speed—because changes in these parameters can greatly impact aircraft performance and safety. Sudden drops or increases in either can lead to challenges in maintaining control of the aircraft, making it crucial for pilots to recognize these conditions during flight operations.

Other thresholds mentioned, such as airspeed changes greater than 10 knots or vertical speed changes of 400 feet per minute, might indicate less severe windshear but do not meet the criteria for what is classified as severe. Similarly, sudden fluctuations in altitude, while potentially indicative of windshear or other issues, do not specifically define severe windshear as effectively as the parameters set forth in the correct answer.