Definition
A high-lift system that uses high-pressure air, typically bled from the engine compressor, blown through narrow slots over the upper surface of the wing or flap. This added energy keeps the airflow attached at higher angles of attack and lower speeds than the wing could sustain on its own, increasing maximum lift and lowering stall speed.
Plain English
A system that pipes high-pressure air over the top of the wing to keep the air flowing smoothly across it. This lets the aircraft fly slower without stalling.
Context Anchor
Seen in discussions of slow-speed flight, high-lift systems, and aircraft designs that need extra lift for takeoff, landing, or very slow flight.
Derivation
The term describes exactly what the system does: it blows air to control the boundary layer, which is the thin sheet of slow-moving air clinging to the wing's surface. When that layer separates from the wing, lift collapses and the wing stalls. Blowing energy back into it keeps it attached.
Why Pilots Care
It permits lower approach and stall speeds while preserving control, shortening takeoff and landing distances on equipped aircraft.
Grounding Statement
Picture a thin film of air sliding along the top of the wing. At slow speeds it wants to peel away; blowing fresh high-pressure air through a slot pushes it back down and keeps it flowing.
Intuition Check
Blowing does not mean natural wind here. It means the aircraft deliberately sends pressurized air over the wing or flap to improve airflow.
Example Sentence 1
With blowing boundary layer control active, the aircraft could maintain controlled flight at approach speeds well below those of a conventional wing.
Example Sentence 2
During slow-flight practice the pilot observed how blowing boundary layer control delayed the onset of buffet.