FAA Aircraft Dispatcher (ADX)Flight Planning and PerformanceMedium
A dispatcher notes a low-level wind shear alert for the destination airport, with a reported 20-knot airspeed loss on final approach. What is the primary hazard this presents to the flight?
- AA rapid decrease in airspeed that can cause the aircraft to sink below the desired glidepath with insufficient altitude to recover.
- BA change in magnetic heading requiring selection of an alternate approach course.
- CAn increase in engine fuel flow that reduces range for the arrival.
- DAn increase in groundspeed that will shorten the landing roll.
Show answer & explanationAnswer & explanation
Correct answer: A. A rapid decrease in airspeed that can cause the aircraft to sink below the desired glidepath with insufficient altitude to recover.
Low-level wind shear that produces a sudden loss of headwind (or airspeed) reduces lift and can cause the aircraft to sink below the glidepath, which is especially dangerous at low altitude where there is little margin for recovery.
Why the other options are wrong
- B. Wind shear is a performance/safety hazard, not primarily a heading/navigation issue.
- C. Wind shear affects aerodynamic performance, not fuel flow economy directly.
- D. A loss of airspeed does not increase groundspeed or shorten landing roll; it degrades performance.
Low-Level Wind Shear (LLWS)
A sudden change in wind speed/direction near the surface that can cause rapid airspeed loss or gain, threatening approach and landing safety.
- Airspeed loss is most hazardous on approach (risk of sinking below glidepath)
- Airspeed gain can cause a ballooning effect above glidepath
- LLWAS and PIREPs are primary detection tools
Memory trick: Losing airspeed near the ground is like losing your footing on a ledge.