How does wind shear affect aircraft during takeoff and landing?

• A. It enhances lift.
• B. It can cause sudden changes in airspeed and vertical wind component, reducing lift.
• C. It only affects engine thrust.
• D. It has no effect on takeoff/landing.

Answer: (D)

Wind shear is a rapid change in wind speed and/or direction over a short distance. Near the ground during takeoff and landing, the airplane is already operating with high lift demand and is highly sensitive to changes in the airflow it experiences.

When wind shear occurs, the relative wind hitting the wing can suddenly become weaker or stronger, and the vertical wind component can shift from updrafts to downdrafts or vice versa. Because lift depends on the airspeed through the wing (dynamic pressure) and the angle of attack, a sudden drop in headwind (or an abrupt tailwind) reduces the airspeed and can lower lift, while an abrupt updraft or downdraft can push the aircraft up or down unexpectedly. These rapid changes can destabilize the airplane or even bring it close to stall if lift falls too quickly.

So, wind shear affects takeoff and landing by causing sudden changes in airspeed and the vertical component of wind, which can reduce lift and make those phases of flight particularly hazardous.