Definition
A cockpit warning indicator that illuminates when the airplane's angle of attack approaches the critical (stalling) angle, alerting the pilot that a stall is imminent unless corrective action is taken. It is typically driven by an angle-of-attack sensor or a vane/lift transducer mounted on the wing leading edge.
Plain English
A light that comes on in the cockpit to tell the pilot the wing is about to stop flying. It is an early warning so the pilot can lower the nose and add power before the airplane actually stalls.
Context Anchor
Seen during slow flight, stall practice, and multiengine VMC demonstrations, where the first stall warning is a cue to recover rather than continue slowing the airplane.
Derivation
“Stall” originally meant to stop or come to a standstill. In aviation, it refers to the wing no longer making normal lift because the airflow over it has broken down. “Warning light” is the cockpit light that alerts the pilot before that condition fully develops.
Why Pilots Care
Gives the pilot an early cue to lower the nose and prevent a full stall that could lead to loss of control.
Grounding Statement
When the stall warning light comes on, the airplane is telling you that the wing is near the point where it may stop producing normal lift.
Intuition Check
Do not read “stall” here as the engine stopping. A stall warning light is warning about the wing getting too close to an aerodynamic stall, not about the engine quitting.
Example Sentence 1
As the pilot slowed the airplane during the power-off stall, the stall warning light illuminated several knots before the wing actually broke.
Example Sentence 2
The pilot saw the stall warning light and immediately reduced back pressure to regain flying speed.