Definition
The disturbed air left behind a flying aircraft, consisting primarily of two counter-rotating vortices trailing from the wingtips, along with jet engine exhaust, propeller wash, and rotor downwash. These wingtip vortices are a byproduct of the lift the aircraft is producing and can persist for several minutes, sinking and drifting with the wind. Following aircraft that fly into them can experience sudden, severe rolling moments and loss of control, especially when the leading aircraft is heavier, slower, and in a clean configuration.
Plain English
The invisible swirling air an aircraft leaves behind it as it flies. Bigger and slower aircraft leave stronger swirls, and flying into them can flip or upset a smaller aircraft.
Context Anchor
You will hear about wake turbulence during takeoff, landing, taxi, and when following or crossing behind another aircraft, especially a large jet or helicopter.
Derivation
‘Wake’ comes from old Norse and originally described the trail of disturbed water left behind a moving ship. Aviation borrowed the word directly: an aircraft leaves a similar trail of disturbed air. ‘Turbulence’ comes from Latin turbulentus, meaning ‘full of commotion.’ Together, the term describes the churned-up air trailing an aircraft.
Why Pilots Care
It can produce sudden roll or loss of control; pilots must maintain specific separation distances behind heavier aircraft to avoid it.
Analogy
Think of the swirl a boat leaves behind in calm water. The boat is long gone, but the rolling wake can still rock a smaller boat that crosses it. Aircraft do the same thing in the air — only you can’t see it.
Grounding Statement
Picture a large airplane passing through calm air and leaving invisible swirling air behind it that takes time to move away and weaken.
Intuition Check
Do not assume wake turbulence is only the visible or bumpy air directly behind an aircraft in flight. It can be invisible, can drift with the wind, and can also come from jet engines, propellers, or helicopter rotors on or near the ground.
Example Sentence 1
Tower advised the Cessna to extend its downwind for wake turbulence behind the departing 737.
Example Sentence 2
Controllers issue wake turbulence advisories based on aircraft weight class when sequencing departures.