Definition
A wind shear condition in which an aircraft transitions from a tailwind into a headwind, or into calm air, over a short distance or time. The sudden loss of the tailwind component causes a rapid increase in indicated airspeed and a tendency for the aircraft to balloon above the intended flight path.
Plain English
The wind that was pushing the aircraft from behind suddenly weakens or reverses. Because the air now meets the aircraft head-on (or stops moving with it), the airspeed jumps up and the aircraft rises above where the pilot wanted it to be.
Context Anchor
Seen in thunderstorm and microburst wind shear discussions, especially during takeoff, landing, or low-altitude flight near heavy rain or storm cells.
Derivation
‘Shearing’ comes from the idea of one layer of air sliding past another, like fabric being cut. Here it describes the boundary where one wind condition gives way to another over a short distance.
Why Pilots Care
The sudden airspeed gain or loss can trigger stall warnings, require rapid power and pitch corrections, and has contributed to loss-of-control events on approach or departure.
Grounding Statement
Imagine running with a strong wind at your back, then turning a corner and suddenly facing into the wind — your sense of speed jumps even though your legs are doing the same thing.
Intuition Check
Shearing does not mean the wind is physically cutting the airplane. Here it means the wind changes quickly in speed or direction over a short distance or time.
Example Sentence 1
On final approach behind a passing storm, the crew encountered a tailwind shearing to calm and saw airspeed rise sharply as the aircraft ballooned above the glide path.
Example Sentence 2
The crew briefed the possibility of tailwind shearing to headwind or calm before descending through the thunderstorm outflow layer.