Basic "V"-Speeds

V stands for “vitesse,” another aviation term borrowed from the French; “vitesse” being the French

word for “speed” or “rate.”

Now for the definition: V-speeds are the airspeeds defined for specific maneuvers in specific aircraft at specific configurations (e.g., flaps, gear).

Performance:

Vr

Rotation speed. As stated in 14 CFR part 23, VR is “the speed at which the pilot makes a control input, with the intention of lifting the airplane out of contact with the runway or water surface.”  To reduce the possibility of an inadvertent stall during takeoff, regulations state that VR cannot be less than VS1.

Vx

VX represents the airspeed for best angle of climb, and it results in the greatest amount of altitude over the shortest distance.  You’ll want to use this speed for a short-field takeoff, especially if you need to clear obstacles in the departure path.  It’s important to practice this maneuver (and flying at this airspeed) on a regular basis, because lack of experience and/or proficiency in short-field / obstacle clearance operations could lead to an inadvertent takeoff/departure stall.

Vy

VY is the airspeed for best rate of climb, which produces the greatest amount of altitude gain over the shortest period of time. VY is the “standard” airspeed to establish during the post-takeoff climb and departure phase of flight.

Limitations:

Va

VA is the aircraft’s design maneuvering speed. Flying at or below VA, means that the airplane will stall before the structure is damaged by excessive loads.  If you encounter a gust that causes a sudden, significant increase in load factor while flying above VA, the aircraft could experience structural failure. 

Another important thing to understand is that VA changes with the aircraft weight: VA decreases as weight decreases, and it increases as aircraft weight increases.

It is a mistake to assume that as long as you are at or below VA, you can move the controls from stop to stop repeatedly without damaging the aircraft.  To clarify this point, 14 CFR part 25 states that “flying at or below the design maneuvering speed does not allow a pilot to make multiple large control inputs in one airplane axis or single full control inputs in more than one airplane axis at a time without endangering the airplane’s structure.”  Although GA aircraft are certificated under 14 CFR part 23, this point is still valid.

Vfe

Represented by the top of the white arc on the airspeed indicator, VFE is the maximum flap extended speed. If you allow your airspeed to increase above VFE with flaps extended, you may damage or even lose one or both flaps.  Note that some aircraft are designed to allow partial flap extension above VFE, so consult the Pilot Operating Handbook/Aircraft Flight Manual to be sure you understand the limitations for your specific make and model.

Vle

VLE represents the maximum airspeed for operating with the landing gear extended. A related speed is VLO, which is the maximum speed for “operating” (extending or retracting) the landing gear.

Vne

This one is easy – “never exceed” means exactly what it says. It is an absolute limit, and you should never, ever operate as if there were a “buffer” beyond this speed.  Such assumptions are likely to result in structural failure.

Vno

Maximum structural cruising speed — the highest speed that you can safely fly in smooth air — is shown as the upper limit of the green arc on the airspeed indicator.  If you fly above VNO — in the yellow arc or “caution range” — and you encounter air that is not smooth, you could cause damage to the aircraft.

Vs

VS is the stalling speed, or the minimum steady flight speed at which the airplane is controllable — in other words, the airplane will stall if you fly any slower than this speed.  Although the “stalling speed” part of the definition leads pilots to believe they can avoid a stall by flying at or above a specific numerical value, it is very important to understand that a stall results from exceeding the critical angle of attack.  It’s better to think of VS not as a numerical value, but rather the point at which your airplane is at the critical angle of attack in straight-and-level flight.  A stall can occur at any airspeed, in any attitude.  VS is the point at which the air flowing over the upper surface of the wing can no longer flow smoothly to the trailing edge.