Definition
The speed of the aircraft relative to the ground at the moment the wheels make contact with the runway during landing. It is a key variable in landing performance calculations because the kinetic energy that must be dissipated during the landing roll is proportional to the square of this speed.
Plain English
How fast the airplane is moving over the ground when it touches down on the runway.
Context Anchor
Used in landing performance discussions when estimating landing distance and understanding how wind, weight, and approach speed affect the runway needed after touchdown.
Derivation
Velocity comes from the Latin velocitas, meaning swiftness or speed. In physics and aviation, velocity refers to speed in a specific direction — here, the aircraft's forward speed across the runway surface at touchdown.
Why Pilots Care
Directly determines minimum runway length needed and influences braking distance and tire stress.
Intuition Check
Landing velocity does not mean the airplane’s rate of descent. Here it means the airplane’s forward speed at touchdown, especially over the runway surface.
Example Sentence 1
A higher landing velocity means more energy must be absorbed by the brakes, which lengthens the landing roll.
Example Sentence 2
An increase in landing velocity from higher aircraft weight lengthens the required runway distance.