Which statement accurately describes the updates to MagVar Tables?

The correct answer indicates that MagVar Tables are updated every ten years due to changes in the Earth's magnetic field. This is an important aspect of aviation navigation because the magnetic variation— the angle difference between true north and magnetic north—can change over time as the Earth's magnetic field shifts. These shifts are influenced by various geological and atmospheric processes, which can cause gradual changes in magnetic declination at different locations.

MagVar Tables are published by organizations such as the National Oceanic and Atmospheric Administration (NOAA) and are essential for pilots to ensure that their navigation systems reflect the most current magnetic variations. By updating these tables every ten years, aviators can maintain accuracy in navigation calculations, which is critical for safety and effective flight planning.

This systematic approach ensures that all navigational tools that rely on magnetic variation data have the most reliable and accurate information, contributing to the overall safety and efficiency of air travel.