Private Pilot Private Exam

A pilot can expect a wind shear zone in a temperature inversion whenever the windspeed at 2,000 to 4,000 feet above the surface is at least...

1. 10 knots

2. 25 knots

3. 40 knots

4. 50 knots

The correct answer is: 25 knots

In the context of aviation, wind shear refers to a sudden change in wind speed or direction over a short distance, which can significantly affect an aircraft's performance, particularly during takeoff and landing. A temperature inversion occurs when a layer of warm air traps cooler air near the surface, often resulting in a stable atmosphere. This condition can lead to wind shear, especially when there is a notable difference in wind speed between the surface and the upper levels. When wind speeds at 2,000 to 4,000 feet above the surface reach at least 25 knots, the likelihood of encountering an unstable air zone due to wind shear increases. This threshold is significant because wind shear can lead to dangerous situations, especially during critical phases of flight. In contrast, lower wind speeds such as 10 knots may not create considerable changes in wind dynamics, while speeds of 40 knots or higher exacerbate the potential for severe turbulence and wind variations but are less indicative of the initial conditions that signal wind shear linked to temperature inversions. Therefore, 25 knots represents a critical point where pilots should be vigilant for the possibility of wind shear due to the presence of a temperature inversion.