Understanding Aircraft Direction
Aircraft Heading (HDG), Track (TR), and Track Made Good (TMG)
Understanding the definitions of heading, track, and track made good is essential for effective navigation in aviation.
Aircraft Heading (HDG)
Definition: Aircraft Heading is the direction in which the longitudinal axis of an aircraft is pointed, measured in degrees clockwise from North. Headings can be measured using True, Magnetic, Compass, or Grid references.
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Track (TR)
Definition: Track is the projection on the Earth’s surface of the path of an aircraft. It is expressed in degrees from North and represents the aircraft’s intended path over the ground.
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Track Made Good (TMG)
Definition: Track Made Good is the actual path traveled by the aircraft over the ground.
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Compass (C), Magnetic (M), and True (T) Directions
Compass (C)
Definition: Compass heading refers to an aircraft’s direction as indicated by a compass, accounting for compass error due to deviation.
Magnetic (M)
Definition: Magnetic heading is the direction an aircraft is flying concerning Magnetic North, as indicated by a magnetic compass.
Note: Magnetic variation (declination) is the angular difference between True North and Magnetic North.
True (T)
Definition: True heading is the direction relative to the geographic North Pole (True North). Calculated by adjusting the magnetic heading with magnetic variation.
Direction Expression Methods
Three-Figure Groups
Description: Directions are expressed as three-digit numbers representing degrees on a compass, always referenced from True North.
Examples:
- North: 000°
- East: 090°
- South: 180°
- West: 270°
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Two-Figure Groups
Description: Directions can also be expressed using two digits, typically for convenience in fewer complex situations.
Clock Code
Description: Uses positions on an analog clock face to communicate relative directions around an aircraft.
Examples:
- “12 o’clock” is straight ahead.
- “3 o’clock” is directly right.
- Altitude can be added, such as “12 o’clock high” indicating ahead and above.
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Conclusion
The definitions and direction expression methods covered are fundamental for effective navigation and communication in aviation. Understanding the use of heading, track, and track made good, as well as compass, magnetic, and true directions ensures pilots can navigate accurately and safely.