Aeronautical Terms beginning with V

V1

The maximum speed in the takeoff at which the pilot must take the first action (e.g., apply brakes, reduce thrust, deploy speed brakes) to stop the airplane within the accelerate-stop distance. Also the minimum speed in the takeoff, following a failure of the critical engine at Vef, at which the pilot can continue the takeoff and achieve the required height above the takeoff surface within the takeoff distance.

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V2

Takeoff Safety Speed.

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Vef

The speed at which the critical engine is assumed to fail during takeoff.

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Vfto

Final Takeoff Speed.

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Vmc

Minimum control airspeed. This is the minimum flight speed at which a twin-engine airplane can be satisfactorily controlled when an engine suddenly becomes inoperative and the remaining engine is at takeoff power.

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Vmu

Minimum unstick speed.

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Vs1

The stalling speed or the minimum steady flight speed obtained in a specified configuration. For most airplanes, this is the power-off stall speed at the maximum takeoff weight in the clean configuration (gear up, if retractable, and flaps up). The lower limit of the green arc.

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Vsse

Safe, intentional one-engine inoperative speed. The minimum speed to intentionally render the critical engine inoperative.

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Vsw

Speed at which onset of natural or artificial stall warning occurs.

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Vxse

Best angle of climb speed with one engine inoperative. The airspeed at which an airplane gains the greatest amount of altitude in a given distance in a light, twin-engine airplane following an engine failure.

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Vyse

Best rate-of-climb speed with one engine inoperative. This airspeed provides the most altitude gain in a given period of time in a light, twin-engine airplane following an engine failure.

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Vyse

Best rate-of-climb speed with one engine inoperative. This airspeed provides the most altitude gain in a given period of time in a light, twin-engine airplane following an engine failure.

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