How can you obtain magnetic variation for your route card?

Obtaining magnetic variation is essential for accurate navigation and is best achieved by adding or subtracting from grid north, as this allows pilots to convert between true north and magnetic north. Magnetic variation, also known as magnetic declination, is the angle difference between these two norths and is necessary for accurate heading and route planning.

Grid north refers to the direction of the north pole as defined in the grid system used on navigation charts. When pilots use navigational charts, the grid north is typically depicted, while magnetic north may differ due to geographical location and changes over time. By applying the magnetic variation specific to the region of operation to the grid north, pilots can determine the correct magnetic heading needed for their route.

In contrast, using a compass reading can lead to inaccuracies because compasses are influenced by local magnetic fields and may not reflect true magnetic variation. Estimating based on experience might provide a rough idea but lacks precision, especially over long distances or varied terrain. Relying solely on GPS data can also be misleading as it often provides true heading information, necessitating the conversion to magnetic headings, which again requires knowledge of magnetic variation.