FAA Commercial Pilot Airplane (CAX)WeatherEasy
A pilot observes a sudden decrease in indicated airspeed accompanied by an increase in vertical speed while on final approach. This condition is most likely indicative of encountering which type of wind shear?
- ADecreasing headwind shear
- BDecreasing tailwind shear
- CIncreasing tailwind shear
- DIncreasing headwind shear
Show answer & explanationAnswer & explanation
Correct answer: A. Decreasing headwind shear
A decreasing headwind shear reduces the airflow over the wings, leading to a loss of lift and a corresponding decrease in indicated airspeed. To compensate for the loss of lift, the aircraft will descend more rapidly, resulting in an increase in vertical speed.
Why the other options are wrong
- B. A decreasing tailwind shear would cause an increase in groundspeed, but the immediate effect on indicated airspeed is less direct and usually involves a decrease in indicated airspeed if the pilot maintains attitude.
- C. An increasing tailwind shear would typically cause a decrease in groundspeed, but the immediate effect on indicated airspeed is less direct and often involves an increase in indicated airspeed if the pilot maintains attitude.
- D. An increasing headwind shear would typically cause an increase in indicated airspeed and a decrease in vertical speed.
Wind Shear
A sudden change in wind speed or direction over a short distance, which can significantly affect aircraft performance.
- Can occur horizontally or vertically.
- Often associated with fronts, thunderstorms, and inversions.
- Critical during takeoff and landing phases.
Memory trick: Shear's a steal, it'll slow your wheel. Headwind's gone, your descent is drawn.