Aircraft Speeds
| 30 March 2010
Limiting and recommended V speeds
V1 — Takeoff decision speed (multi); formerly denoted as critical engine failure speed.
V2 — Takeoff safety speed (multi).
V2 MIN — Minimum takeoff safety speed (multi).
VA — Maneuvering speed, the maximum speed at which application of full available aerodynamic control will not overstress the airplane; usually decreases as gross weight decreases.
VB — Design speed for maximum gust intensity.
VC — Design cruising speed.
VD — Design diving speed.
VDF/MDF — Demonstrated flight diving speed.
VEF — Critical engine failure speed, the speed at which the engine was failed during certification flight testing to determine accelerate-stop and accelerate-go distances.
VF — Design flap speed.
VFC/MFC — Maximum speed for stability characteristics.
VFE — Maximum flap-extended speed, the highest speed permissible with wing flaps in a prescribed extended position; top of white arc.
VH — Maximum speed in level flight with maximum continuous power.
VLE — Maximum landing gear extended speed.
VLO — Maximum landing gear operating speed.
VLOF — Liftoff speed.
VMC — Minimum control speed with the critical engine inoperative (multi).
VMCA — Minimum control speed with the critical engine inoperative out of ground effect — red radial line (multi).
VMCG — Minimum control speed with critical engine inoperative during takeoff roll (multi).
VMO/MMO — Maximum operating limit speed, the speed that may not be deliberately exceeded at any time; redline or "barber pole" (turboprop/jet).
VMU — Minimum unstick speed.
VNE — Never-exceed speed, the speed that may not be exceeded at any time; redline.
VNO — Maximum structural cruising speed, the speed that should not be exceeded except in smooth air and then only with caution; top of green arc.
VR — Rotation speed.
VREF — Reference speed for final approach, usually 1.3 times VSO.
VS — Stall speed or minimum steady flight speed at which the airplane is controllable.
VS1 — Stall speed or minimum steady flight speed obtained in a specific configuration.
VSO — Stall speed or minimum steady flight speed at which the airplane is controllable in the landing configuration; bottom of white arc.
VSSE — Minimum safe single-engine speed (multi).
VTOSS — Takeoff safety speed for Category A rotorcraft.
VX — Best angle-of-climb speed, the airspeed that delivers the greatest gain of altitude in the shortest possible horizontal distance.
VXSE — Best single-engine angle-of-climb speed (multi).
VY — Best rate-of-climb speed, the airspeed that delivers the greatest gain in altitude in the shortest possible time.
VYSE — Best single-engine rate-of-climb speed (multi).
Airspeed indicator markings
Red radial line — Never-exceed speed (VNE); also, for twin-engine aircraft, minimum control speed with critical engine inoperative (VMC).
Redline or barber pole — Maximum operating limit speed, the speed that may not be deliberately exceeded at any time for turboprop/jet aircraft (VMO/MMO).
Yellow arc — Caution range between maximum structural cruise speed (VNO) and never-exceed speed (VNE).
Green arc — Normal operating range; upper limit is maximum structural cruise speed (VNO); lower limit is power-off stall speed or minimum steady flight speed in a specific configuration — usually with flaps and landing gear retracted (VS1).
White arc — Flap operating range; upper limit is maximum full flaps extended speed (VFE); lower limit is power-off stall speed or minimum steady flight speed in the landing configuration — usually with full flaps and landing gear extended (VSO).
White triangle — Standard designator used for certain speed limitations; for example, maximum flap-extended speed with flaps in a prescribed extended position (VFE) or maximum landing gear extended speed (VLE); the manufacturer determines the type of speed limitation for which the designator is used.
Blue radial line or arc — For twin-engine aircraft, one-engine inoperative best rate-of-climb speed (VYSE).