What is variation in aviation navigation?

Variation in aviation navigation refers to the difference between magnetic north and true north. In navigation, true north is defined based on the Earth's geographic North Pole, while magnetic north is determined by the Earth's magnetic field and can shift over time and location. This difference is significant for accurate navigation because aviation instruments often rely on magnetic headings.

When pilots calculate their course or heading using magnetic compasses, they must take variation into account to ensure that they are aligning their navigation with true north. This adjustment is essential for achieving accurate flight paths and reaching the intended destination. Each geographic region has its own variation value, which can be found on aeronautical charts, allowing pilots to make necessary corrections.