Definition
The minimum airspeeds at which an aircraft can maintain controlled flight in specified configurations. On the airspeed indicator, key stall speeds are marked by colored arcs and lines: the lower limit of the white arc shows the stall speed in landing configuration (flaps and gear down), and the lower limit of the green arc shows the stall speed in clean configuration (flaps and gear up) at maximum gross weight.
Plain English
The slowest speeds at which the wings can still keep the aircraft flying normally. Below these speeds, the wings stop producing enough lift and the aircraft stalls.
Context Anchor
You see stall speeds on the airspeed indicator’s colored markings, such as the lower ends of the white and green bands, and in the aircraft’s operating handbook.
Derivation
‘Stall’ in aviation comes from the older sense of an engine or motion ‘stopping’ or ‘coming to a halt.’ When applied to wings, it describes the point where lift breaks down — the wing effectively stops doing its job, even though the aircraft is still moving.
Why Pilots Care
Knowing stall speeds lets pilots maintain safe margins above the point where the airplane loses lift and control, especially during takeoff, landing, and slow-flight practice.
Grounding Statement
A stall speed is the speed where the airplane is at the edge of having enough lift for the way it is currently configured and flown.
Intuition Check
Do not read “stall” here as “the engine quits.” A stall speed is about the wing losing smooth lift, not the engine stopping.
Example Sentence 1
Before turning final, she added a few knots above the published stall speed to allow for the bank angle in the turn.
Example Sentence 2
During the landing approach the pilot kept airspeed comfortably above stall speed to maintain full control all the way to touchdown.