UPWIND LEG A flight path parallel to the landing runway in the direction of landing.

VEHICLE Man-made means of transportation; an ultralight aircraft (not a light-sport aircraft).

VENTURI A specially shaped restriction in a tube designed to speed up the flow of fluid passing through in accordance with Bernoulli’s principle. Venturis are used in carburetors and in many types of fluid control devices to produce a pressure drop proportional to the speed of the fluid passing through them.

VENTURI EFFECT The effect of Bernoulli’s principle, which states that the pressure of a fluid decreases as it is speeded up without losing or gaining any energy from the outside.

VERIFIED Confirmation of information or configuration status.

VERTICAL AXIS (YAW) An imaginary line passing vertically through the center of gravity of an aircraft. The vertical axis is called the z-axis or the yaw axis.

VERTICAL SPEED INDICATOR (VSI) An instrument that uses static pressure to display a rate of climb or descent in feet per minute. The VSI can also sometimes be called a vertical velocity indicator (VVI).

VERTIGO A type of spatial disorientation caused by the physical senses sending conflicting signals to the brain. Vertigo is especially hazardous when flying under conditions of poor visibility and may cause pilot incapacitation, but may be minimized by confidence in the indication of the flight instruments.

VFR See VISUAL FLIGHT RULES.

VFR TERMINAL AREA CHARTS Charts designated to depict Class B airspace in greater detail and greater scale than sectional charts.

VISUAL FLIGHT RULES (VFR) Code of Federal Regulations that govern the procedures for conducting flight under visual conditions.

V LINES See RISERS.

VSI See VERTICAL SPEED INDICATOR.

WAKE TURBULENCE Wingtip vortices that are created when an aircraft generates lift. When an aircraft generates lift, air spills over the wingtips from the high pressure areas below the wings to the low pressure areas above them. This flow causes rapidly rotating whirlpools of air called wingtip vortices or wake turbulence.

WASHOUT A condition in aircraft rigging in which a wing is twisted so its angle of incidence is less at the tip than at the root. Washout decreases the lift the wing produces to improve the stall characteristics of the wing.

WEATHER BRIEFING Means for pilots to gather all information vital to the nature of the flight. Most often obtained from FSS specialist.

WEATHERVANE The tendency to point into the wind.

WEIGHT A measure of the heaviness of an object. The force by which a body is attracted toward the center of the Earth (or another celestial body) by gravity. Weight is equal to the mass of the body times the local value of gravitational acceleration. One of the four main forces acting on an aircraft. Equivalent to the actual weight of the aircraft. It acts downward through the aircraft’s center of gravity toward the center of the Earth. Weight opposes lift.