Glossary

V NE . The never-exceed speed. Operating above this speed is W prohibited since it may result in damage or structural failure. WAAS. See wide area augmentation system. The red line on the airspeed indicator. Wake turbulence. Wingtip vortices that are created when V . The maximum structural cruising speed. Do not NO an airplane generates lift. When an airplane generates lift, exceed this speed except in smooth air. The upper limit of air spills over the wingtips from the high pressure areas the green arc. below the wings to the low pressure areas above them. This flow causes rapidly rotating whirlpools of air called wingtip VOR. See very-high frequency omnidirectional range. vortices or wake turbulence. VORTAC. A facility consisting of two components, VOR Warm front. The boundary area formed when a warm air and TACAN, which provides three individual services: VOR mass contacts and flows over a colder air mass. Warm fronts azimuth, TACAN azimuth, and TACAN distance (DME) cause low ceilings and rain. at one site. Warning area. An area containing hazards to any aircraft VOR test facility (VOT). A ground facility which emits a not participating in the activities being conducted in the test signal to check VOR receiver accuracy. Some VOTs are area. Warning areas may contain intensive military training, available to the user while airborne, while others are limited gunnery exercises, or special weapons testing. to ground use only. WARP. See weather and radar processing. VOT. See VOR test facility. Waste gate. A controllable valve in the tailpipe of an aircraft VSI. See vertical speed indicator. reciprocating engine equipped with a turbocharger. The valve is controlled to vary the amount of exhaust gases forced V .The stalling speed or the minimum steady flight speed S0 through the turbocharger turbine. in the landing configuration. In small airplanes, this is the power-off stall speed at the maximum landing weight in the Waypoint. A designated geographical location used for route landing configuration (gear and flaps down). The lower limit definition or progress-reporting purposes and is defined in of the white arc. terms of latitude/longitude coordinates. V .The stalling speed or the minimum steady flight speed S1 WCA. See wind correction angle. obtained in a specified configuration. For most airplanes, this is the power-off stall speed at the maximum takeoff weight Weather and radar processor (WARP). A device that in the clean configuration (gear up, if retractable, and flaps provides real-time, accurate, predictive, and strategic weather up). The lower limit of the green arc. information presented in an integrated manner in the National Airspace System (NAS). V-tail. A design which utilizes two slanted tail surfaces to perform the same functions as the surfaces of a conventional Weather depiction chart. Details surface conditions as elevator and rudder configuration. The fixed surfaces act as derived from METAR and other surface observations. both horizontal and vertical stabilizers. Weight. The force exerted by an aircraft from the pull of V . Best angle-of-climb speed. The airspeed at which an X gravity. airplane gains the greatest amount of altitude in a given distance. It is used during a short-field takeoff to clear an Wide area augmentation system (WAAS). A differential obstacle. global positioning system (DGPS) that improves the accuracy of the system by determining position error from the GPS V . Best rate-of-climb speed. This airspeed provides the Y satellites, then transmitting the error, or corrective factors, most altitude gain in a given period of time. to the airborne GPS receiver. V . Best rate-of-climb speed with one engine inoperative. YSE Wind correction angle (WCA). The angle between the This airspeed provides the most altitude gain in a given desired track and the heading of the aircraft necessary to period of time in a light, twin-engine airplane following an keep the aircraft tracking over the desired track. engine failure. G-34