Definition
The maximum speed at which a sudden, full deflection of a single flight control will cause the airplane to stall before the airframe is overstressed beyond its design load limit. VA is published in the airplane's flight manual and typically varies with weight, decreasing as weight decreases.
Plain English
The fastest speed at which you can yank a control fully in one direction and have the wing stall before anything bends or breaks. Below this speed, the airplane will run out of lift before it runs out of strength.
Context Anchor
You will see VA in the airplane manual, on some cockpit placards, and in training discussions about steep turns, stalls, turbulence, and other situations where the airplane may be loaded more than in straight-and-level flight.
Derivation
The 'V' in VA comes from the French word 'vitesse,' meaning speed. Aviation borrowed many speed labels from early French aeronautical work, which is why most reference speeds begin with V (VS, VNE, VX, VY, and so on). The 'A' stands for the type of speed — in this case, maneuvering.
Why Pilots Care
Staying at or below VA during turbulence or aggressive maneuvers prevents structural overload that could lead to failure of wings or control surfaces.
Grounding Statement
At or below VA, one sudden full control input should make the wing stall before the airplane structure is overloaded.
Intuition Check
VA does not mean the airplane is protected from any rough handling at any speed below it. It applies to a single sudden full control input, not repeated, opposite, or combined control movements, and it must be adjusted lower when the airplane is lighter.
Example Sentence 1
Before entering the area of reported turbulence, the pilot slowed the airplane to VA to protect the airframe from gust loads.
Example Sentence 2
In rough air the pilot kept speed at or below VA to avoid gust-induced overload on the wings.