Regulatory V-speeds
These V-speeds are defined by regulations.
| V-speed designator | Description |
|---|---|
| V1 | Critical engine failure recognition speed. (See V1 definitions below) |
| V2 | Takeoff safety speed. The speed at which the aircraft may safely become airborne 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 maneuvering 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 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. 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. |
| VDF | Demonstrated flight diving speed. |
| 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 it is safe to fly a retractable gear aircraft with the landing gear extended. |
| VLO | Maximum landing gear operating speed. This is the maximum speed at which it is safe to extend or retract the landing gear on a retractable gear aircraft. |
| VLOF | Lift-off speed. |
| VMC | Minimum control speed with Critical engine inoperative. |
| Vmca | Minimum control speed in the take-off configuration – the minimum calibrated airspeed at which the aircraft is directionally controllable in flight with a sudden Critical engine failure and takeoff power on the operative engine(s). |
| Vmcg | Minimum control speed on the ground - the minimum airspeed at which the aircraft is directionally controllable during acceleration along the runway with one engine inoperative, takeoff power on the operative engine(s), and with nose wheel steering assumed inoperative. |
| 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 maneuvering speed. |
| VR | Rotation speed. The speed at which the aircraft's nosewheel leaves the ground. Also see note on Vref below. |
| 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. |
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