REGULATORY V-SPEEDS
The following V-speeds are defined by regulations. Some of the descriptions provided are simplified.
V1 The speed beyond which the takeoff should no longer be aborted. (See V1 definitions below)
V2 Takeoff safety speed. The speed at which the aircraft may safely be climbed with one engine inoperative.
V2min Minimum takeoff safety speed.
V3 Flap retraction speed.
V4 Steady initial climb speed. The all engines operating take-off climb speed used to the point where acceleration to flap retraction speed is initiated. Should be attained by a gross height of 400 feet.
VA Design manoeuvring speed. This is the speed above which it is unwise to make full application of any single flight control (or “pull to the stops”) as it may generate a force greater than the aircraft’s structural limitations.
Vat Indicated airspeed at threshold, which is usually equal to the stall speed VS0 multiplied by 1.3 or stall speed VS1g multiplied by 1.23 in the landing configuration at the maximum certificated landing mass, though some manufacturers apply different criteria. If both VS0 and VS1g are available, the higher resulting Vat shall be applied. Also called “approach speed”.
VB Design speed for maximum gust intensity.
VC Design cruise speed, used to show compliance with gust intensity loading.
Vcef See V1; generally used in documentation of military aircraft performance.
VD Design diving speed, the highest speed planned to be achieved in testing.
VDF Demonstrated flight diving speed, the highest actual speed achieved in testing.
VEF The speed at which the critical engine is assumed to fail during takeoff.
VF Designed flap speed.
VFC Maximum speed for stability characteristics.
VFE Maximum flap extended speed.
VFTO Final takeoff speed.
VH Maximum speed in level flight at maximum continuous power.
VLE Maximum landing gear extended speed. This is the maximum speed at which a retractable gear aircraft should be flown with the landing gear extended.
VLO Maximum landing gear operating speed. This is the maximum speed at which the landing gear on a retractable gear aircraft should be extended or retracted.
VLOF Lift-off speed.
VMC Minimum control speed. Mostly used as the minimum control speed for the takeoff configuration (takeoff flaps). Several VMCs exist for different flight phases and airplane configurations: VMCG, VMCA, VMCA1, VMCA2, VMCL, VMCL1, and VMCL2. Refer to the minimum control speed article for a thorough explanation.
VMCA Minimum control speed in the air (or airborne). The minimum speed at which steady straight flight can be maintained when an engine fails or is inoperative and with the corresponding opposite engine set to provide maximum thrust, provided a small (3° – 5°) bank angle is being maintained away from the inoperative engine and the rudder is used up to maximum to maintain straight flight. The exact required bank angle for VMCA to be valid should be provided by the manufacturer with VMC (A) data; any other bank angle results in a higher actual VMC (A). Refer to the minimum control speed article for a description of (pilot-induced) factors that have influence on VMCA. VMCA is also presented as VMC in many manuals.
VMCG Minimum control speed on the ground is the lowest speed at which the takeoff may be safely continued following an engine failure during the takeoff run. Below VMCG, the throttles need to be closed at once when an engine fails, to avoid veering off the runway.
VMCL Minimum control speed in the landing configuration with one engine inoperative.
VMO Maximum operating limit speed.
VMU Minimum unstick speed.
VNE Never exceed speed.
VNO Maximum structural cruising speed or maximum speed for normal operations.
VO Maximum operating manoeuvring speed.
VR Rotation speed. The speed at which the pilot begins to apply control inputs to cause the aircraft nose to pitch up, after which it will leave the ground.
Vrot Used instead of VR (in discussions of the takeoff performance of military aircraft) to denote rotation speed in conjunction with the term Vref (refusal speed).
VRef Landing reference speed or threshold crossing speed. (In discussions of the takeoff performance of military aircraft, the term Vref stands for refusal speed. Refusal speed is the maximum speed during takeoff from which the air vehicle can stop within the available remaining runway length for a specified altitude, weight, and configuration. ) Incorrectly, or as an abbreviation, some documentation refers to Vref and/or Vrot speeds as “Vr.”
VS Stall speed or minimum steady flight speed for which the aircraft is still controllable.
VS0 Stall speed or minimum flight speed in landing configuration.
VS1 Stall speed or minimum steady flight speed for which the aircraft is still controllable in a specific configuration.
VSR Reference stall speed.
VSR0 Reference stall speed in landing configuration.
VSR1 Reference stall speed in a specific configuration.
VSW Speed at which the stall warning will occur.
VTOSS Category A rotorcraft takeoff safety speed.
VX Speed that will allow for best angle of climb.
VY Speed that will allow for the best rate of climb.
Other V-speeds – Some of these V-speeds are specific to particular types of aircraft and are not defined by regulations.
VBE Best endurance speed – the speed that gives the greatest airborne time for fuel consumed.
VBG Best power-off glide speed – the speed that provides maximum lift-to-drag ratio and thus the greatest gliding distance available.
VBR Best range speed – the speed that gives the greatest range for fuel consumed – often identical to Vmd.
VFS Final segment of a departure with one powerplant failed.
Vimd Minimum drag
Vimp Minimum power
VLLO Maximum landing light operating speed – for aircraft with retractable landing lights.
Vmbe Maximum brake energy speed
Vmd Minimum drag (per lift) – often identical to VBR.[20][23] (alternatively same as Vimd)
Vmin Minimum speed for instrument flight (IFR) for helicopters
Vmp Minimum power
Vms Minimum sink speed at median wing loading – the speed at which the minimum descent rate is obtained. In modern gliders, Vms and Vmc have evolved to the same value.
Vp Aquaplaning speed
VPD Maximum speed at which whole-aircraft parachute deployment has been demonstrated
Vra Rough air speed (turbulence penetration speed).
VSL Stall speed in a specific configuration
Vs1g Stall speed at 1g load factor
Vsse Safe single engine speed
Vt Threshold speed
VTD Touchdown speed
VTGT Target speed
VTO Take-off speed. (see also VLOF)
Vtocs Take-off climbout speed (helicopters)
Vtos Minimum speed for a positive rate of climb with one engine inoperative
Vtmax Max threshold speed
Vwo Maximum window or canopy open operating speed
VXSE Best angle of climb speed with a single operating engine in a light, twin-engine aircraft – the speed that provides the most altitude gain per unit of horizontal distance following an engine failure, while maintaining a small bank angle that should be presented with the engine-out climb performance data.
VYSE Best rate of climb speed with a single operating engine in a light, twin-engine aircraft – the speed that provides the most altitude gain per unit of time following an engine failure, while maintaining a small bank angle that should be presented with the engine-out climb performance data.
VZRC Zero rate of climb speed in a twin-engine aircraft