Magnetic declination changes quite a lot as you travel the kind of distances that aircraft travel. Pilots would have to periodically adjust their declination wh

Magnetic declination changes quite a lot as you travel the kind of distances that aircraft travel. Pilots would have to periodically adjust their declination while flying. Declination is also not linear or varying only by latitude/longitude, but it also varies by area due to magma flows and iron deposits. Take a look at this map of global declinations for reference: https://en.wikipedia.org/wiki/File:World_Magnetic_Declination_2015.pdf https://en.wikipedia.org/wiki/File:World_Magnetic_Declinatio...