NCAA PPL Navigation key terms

The intended direction of flight over the ground, measured in degrees clockwise from true north, drawn on a chart before any wind correction is applied.

The direction the aircraft nose points, measured in degrees clockwise from true north, obtained by applying wind correction to the true course.

The heading the pilot flies after correcting true heading for magnetic variation, read directly on the magnetic compass or directional gyro.

The angular difference at a given location between true north and magnetic north, shown on charts as east or west isogonic lines.

The error in a magnetic compass caused by the aircraft's own magnetic fields and electrical equipment, recorded on a compass correction card.

A line on an aeronautical chart connecting points of equal magnetic variation, labeled with the amount and direction of the variation.

The specific isogonic line along which magnetic variation is zero, so true north and magnetic north coincide along that line.

The angular difference between course and heading needed to offset wind drift, applied toward the wind so the aircraft tracks the desired ground path.

A vector diagram relating true course and true airspeed to wind direction and speed to determine heading and groundspeed for a leg.

The actual speed of the aircraft over the earth's surface, found by combining true airspeed with the wind component along the flight path.

The speed of the aircraft through the air mass, which increases with altitude for a given indicated airspeed because of lower air density.

The speed shown on the airspeed indicator, derived from ram air pressure and used for aircraft performance and maneuvering reference.

Indicated airspeed corrected for installation and position error, which is then corrected for altitude and temperature to obtain true airspeed.

A large-scale VFR chart, typically 1:500,000, showing airports, airspace, navigation aids, terrain, and obstacles for pilotage and dead reckoning.

Navigation by reference to visible landmarks and charted features outside the aircraft, confirming position without relying on instruments.

Navigation by calculating position from a known starting point using course, airspeed, wind, and elapsed time, without outside visual reference.

A prominent charted landmark or navigation aid selected along a route to confirm progress and update estimated time of arrival.

A specified geographical location, defined by coordinates or a navigation aid, that marks a point on a planned route.

A ground-based very high frequency omnidirectional range station that transmits radials, allowing aircraft to determine bearing to or from the station.

A magnetic bearing extending outward from a VOR station, identified by the number of degrees from magnetic north, such as the 090 radial.

Course deviation indicator, the needle in a VOR or GPS display that shows how far the aircraft is left or right of the selected course.

Omni bearing selector, the knob used to choose the desired VOR radial or course displayed on the course deviation indicator.

A VOR display flag showing whether the selected radial, if flown with the current needle indication, leads toward or away from the station.

A non-directional beacon, a low-frequency ground station that transmits a signal an aircraft's automatic direction finder uses to show bearing to the station.

Automatic direction finder, airborne equipment that points a needle toward a selected NDB or broadcast station, showing relative bearing.

The angle measured clockwise from the aircraft's nose to a station, which combined with magnetic heading gives the magnetic bearing to the station.

The direction from the aircraft to a station measured in degrees clockwise from magnetic north, equal to relative bearing plus magnetic heading.

Global Positioning System, a satellite-based navigation system that provides position, groundspeed, and course guidance to equipped aircraft.

Receiver autonomous integrity monitoring, a GPS function that checks satellite signals for consistency and warns the pilot when reliable navigation is not available.

A filed record of intended route, altitude, airspeed, and time, used for search and rescue and for coordinating with air traffic control.

Pilot's operating handbook, the FAA-approved document for a specific aircraft containing performance, limitations, and operating procedures used in flight planning.

The minimum fuel required beyond the planned trip, commonly 30 minutes for day VFR and 45 minutes for night VFR in small aircraft.

The local pressure value dialed into the altimeter so it indicates altitude above mean sea level rather than pressure altitude.

The altitude shown when the altimeter is set to 29.92 inches of mercury, used as the basis for aircraft and engine performance charts.

Pressure altitude corrected for nonstandard temperature, representing the altitude the aircraft performance feels and used to predict takeoff and climb.

Mean sea level, the reference datum for elevations and for altitudes flown at or above the transition altitude in most operations.

Above ground level, a height reference measured from the terrain directly below, used for traffic pattern altitudes and obstacle clearance.

A large number printed in each chart quadrant showing the highest terrain or obstacle elevation in that area, in hundreds of feet.