V Speeds

V Speeds

In aviation, V-speeds are standard terms used to define airspeeds important or useful to the operation of all aircraft including fixed-wing aircraft, gliders, autogiros, helicopters, and dirigibles. These speeds are derived from data obtained by aircraft designers and manufacturers during flight testing and verified in most countries by government flight inspectors during aircraft type-certification testing. Using them is considered a best practice to maximize aviation safety, aircraft performance or both.

The actual speeds represented by these designators are specific to a particular model of aircraft, and are expressed in terms of the aircraft's indicated airspeed, so that pilots may use them directly, without having to apply correction factors.

In general aviation aircraft, the most commonly used and most safety-critical airspeeds are displayed as color-coded arcs and lines located on the face of an aircraft's airspeed indicator. The lower ends of the green arc and the white arc are the stalling speed with wing flaps retracted, and stalling speed with wing flaps fully extended, respectively. These are the stalling speeds for the aircraft at its maximum weight.

Proper display of V speeds is an airworthiness requirement for type-certificated aircraft in most countries.