FAA Private Pilot Helicopter (PRH)WeatherHard
A helicopter pilot is on final approach when the aircraft experiences a sudden increase in headwind followed almost immediately by a strong tailwind and a rapid loss of altitude. What weather phenomenon is most likely responsible for this encounter?
- AA steady, well-developed sea breeze front
- BA microburst associated with a thunderstorm's downdraft
- CMechanical turbulence caused by nearby buildings
- DNormal gusty surface winds from a passing cold front
Show answer & explanationAnswer & explanation
Correct answer: B. A microburst associated with a thunderstorm's downdraft
A microburst produces a strong downdraft that spreads out upon reaching the surface, creating a headwind on approach followed rapidly by a tailwind and significant downdraft as the aircraft passes through the core, resulting in a sudden performance loss and altitude loss. This wind shear phenomenon is extremely hazardous, especially at low altitude on approach.
Why the other options are wrong
- A. A sea breeze front produces a gradual, sustained wind shift, not the abrupt reversal described.
- C. Mechanical turbulence from buildings causes choppy, irregular gusts, not a coherent headwind-to-tailwind shear event.
- D. Ordinary gusty winds do not typically cause such a rapid, extreme reversal with dramatic altitude loss.
Microburst Wind Shear
A microburst is a small-scale, intense downdraft from a thunderstorm or convective cell that produces a rapid change from headwind to tailwind near the surface, hazardous to aircraft on approach or departure.
- Causes airspeed gain (headwind) followed by rapid airspeed loss (tailwind)
- Associated with strong convective downdrafts, especially virga and thunderstorms
- Effects last only a few minutes but can be catastrophic at low altitude
- Recovery requires immediate maximum power application and minimizing altitude loss
Memory trick: Microburst = 'Micro' size but MACRO danger: headwind then tailwind then down