FAA Instrument Rating Airplane (IRA)Weather and Weather ServicesHard
On final approach near a thunderstorm, a pilot notices the airspeed increasing above the target approach speed as the aircraft encounters a rapidly increasing headwind, followed shortly by a sudden loss of airspeed and a strong downdraft. What phenomenon is the pilot most likely experiencing?
- AA microburst
- BClear air turbulence
- CMountain wave activity
- DFrontal wind shear from a slow-moving warm front
Show answer & explanationAnswer & explanation
Correct answer: A. A microburst
A microburst produces a characteristic wind shear signature: an increasing headwind (and often airspeed gain) followed rapidly by a strong downdraft and then a tailwind (airspeed loss) as the aircraft passes through the outflow. This rapid reversal near a thunderstorm at low altitude is a classic and extremely hazardous microburst encounter.
Why the other options are wrong
- B. Clear air turbulence occurs at higher altitudes away from convection and does not produce this headwind/downdraft/tailwind signature.
- C. Mountain wave turbulence occurs downwind of mountains in strong winds, unrelated to thunderstorm proximity.
- D. Frontal wind shear is typically more gradual and associated with a temperature inversion, not this rapid convective signature.
Microburst Wind Shear
A microburst is a small-scale, intense downdraft from a thunderstorm that spreads out at the surface, producing a rapid sequence of increasing headwind, strong downdraft, then increasing tailwind — extremely hazardous during approach or departure.
- Can produce vertical velocities strong enough to exceed aircraft climb performance
- Signature: headwind gain, then downdraft, then tailwind loss
- Typically lasts only a few minutes but can be severe
- Often associated with virga or heavy rain beneath thunderstorms
Memory trick: Microburst: Push in, then Punch down, then Pull out (headwind, downdraft, tailwind)