| A | B |
|---|
| Meridian | Semi-great circle joining poles. |
| Prime Meridian | Datum for longitude. Passes through Greenwich. |
| Equator | Great circle perpendicular to axis rotation of earth. |
| Latitude | Small circles parallel to equator. |
| Great Circle | Circle whose plane passes through centre of earth. |
| Rhumb Line | Curved line cutting meridians at same angle. |
| Variation | Angular difference between True and Magnetic North. |
| Isogonal | Lines joining places of equal variation |
| Agonic Line | Line joining places of zero variation. |
| Deviation | Angular difference between Magnetic North and Compass North |
| Track | Path over surface of earth |
| Heading | Direction aircraft points while in flight. |
| Air Speed | Speed of aircraft through air. (IAS or TAS) |
| Bearing | Direction from an aircraft clockwise from 000 to 359. |
| Wind Velocity | Direction and Speed of Wind |
| Drift | Angular difference between required track and heading. |
| Pilotage | Flying by means of visible landmarks. |
| Track Make Good | Actual path over the ground |
| VFR Navigationalvfr Chart Scale | 1:500 000. 1 inch = 6.86 nm or 8 sm |
| Terminal Area Chart Scale | 1:250 000. 1 inch = 3.43 nm or 4 sm |
| World Aeronautical Chart Scale | 1:1 000 000. 1 inch = 13.7 nm or 16 sm |
| Time Zone Size | 15 Degrees of Longitude |
