How frequently are aeronautical charts updated with new magnetic variation data?

Aeronautical charts are typically updated every 56 days or as new data becomes available to ensure that pilots have the most accurate information concerning magnetic variation. This frequency allows for the regular incorporation of changes in magnetic declination, which can arise due to various factors including the movement of the Earth's magnetic field.

Updating every 56 days also aligns with the schedule for producing and releasing Notices to Airmen (NOTAMs) that include any pertinent changes that may affect flight operations, including those related to magnetic variation. Additionally, if significant changes in magnetic fields occur that affect navigation, those would be addressed immediately, further ensuring pilots have the latest and most reliable data. This approach supports safe and effective navigation, minimizing the risk of errors related to outdated or inaccurate magnetic information.