All V speeds

V1

Engine failure recognition speed. Critical take-off decision speed

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 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. Mostly used as the minimum control speed for the takeoff configuration (takeoff flaps).

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.

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 maneuvering speed.

VR

Rotation speed. The speed at which the aircraft's nosewheel leaves 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.

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

M

Mach number