Describe the impact of magnetic variation on flight navigation.

Magnetic variation, also known as magnetic declination, significantly impacts flight navigation because it is the angular difference between true north and magnetic north. True north is the direction of the geographical North Pole, while magnetic north is the direction a compass needle points, influenced by the Earth's magnetic field. This difference varies depending on location and changes over time. Aeronautical charts and navigational instruments reference both true and magnetic directions. Pilots use these charts to plan their flights using true north for plotting courses, but aircraft compasses indicate magnetic north. To accurately navigate, pilots must correct for magnetic variation. This correction is applied by adding or subtracting the variation from the true course to obtain the magnetic course, or conversely, from the magnetic heading to determine the true heading. For example, if a sectional chart indicates a magnetic variation of 10 degrees East, it means that magnetic north is 10 degrees to the east of true north. A pilot flying a true course of 090 degrees would add 10 degrees to obtain a magnetic course of 100 degrees. Failing to account for magnetic variation can lead to significant navigational errors, causing the aircraft to deviate from its intended course and potentially leading to airspace violations or hazardous situations. Magnetic variation is depicted on aeronautical charts as isogonic lines, which connect points of equal magnetic variation. These lines allow pilots to quickly determine the variation for any location on the chart. Furthermore, electronic navigation systems, such as GPS, often use true north as a reference, automatically correcting for magnetic variation based on the aircraft's location. Despite this, pilots must understand and be able to manually correct for variation in case of equipment failure or when using traditional navigation techniques. Therefore, understanding and correcting for magnetic variation is a fundamental aspect of flight navigation, ensuring accurate course tracking and safe flight operations.