A differential global positioning system (DGPS) that improves the accuracy of the system by determining position error from the GPS satellites, then transmitting the error, or corrective factors, to the airborne GPS receiver.

A standard series of aeronautical charts covering land areas of the world at a size and scale convenient for navigation (1:1,000,000) by moderate speed aircraft. Topographic information includes cities and towns, principal roads, railroads, distinctive landmarks, drainage, and relief. Aeronautical information includes visual and radio aids to navigation, airports, airways, restricted areas, obstructions and other pertinent data.

A measurement of force used to produce movement.

A design feature incorporated into some wings to improve aileron control effectiveness at high angles of attack during an approach to a stall.

The rapidly rotating air that spills over an airplane’s wings during flight. The intensity of the turbulence depends on the airplane’s weight, speed, and configuration. Also referred to as wake turbulence. Vortices from heavy aircraft may be extremely hazardous to small aircraft.

The maximum distance from wingtip to wingtip.

Airfoils attached to each side of the fuselage and are the main lifting surfaces that support the airplane in flight.

The total surface of the wing (in square feet), which includes control surfaces and may include wing area covered by the fuselage (main body of the airplane), and engine nacelles.

A twice-daily forecast that provides wind and temperature forecasts for specific locations in the contiguous United States.

A sudden, drastic shift in windspeed, direction, or both that may occur in the horizontal or vertical plane.

Indicators that include a wind sock, wind tee, or tetrahedron. Visual reference will determine wind direction and runway in use.

The angle between the desired track and the heading of the aircraft necessary to keep the aircraft tracking over the desired track.

The force exerted by an aircraft from the pull of gravity.

Details surface conditions as derived from METAR and other surface observations.

A device that provides real-time, accurate, predictive, and strategic weather information presented in an integrated manner in the National Airspace System (NAS).

See wide area augmentation system.

See wind correction angle.

A designated geographical location used for route definition or progress-reporting purposes and is defined in terms of latitude/longitude coordinates.

A controllable valve in the tailpipe of an aircraft reciprocating engine equipped with a turbocharger. The valve is controlled to vary the amount of exhaust gases forced through the turbocharger turbine.

See weather and radar processing.

An area containing hazards to any aircraft not participating in the activities being conducted in the area. Warning areas may contain intensive military training, gunnery exercises, or special weapons testing.

The boundary area formed when a warm air mass contacts and flows over a colder air mass. Warm fronts cause low ceilings and rain.

Wingtip vortices that are created when an airplane generates lift. When an airplane 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.