Quick Answer
Understanding declination is critical for pilots as it ensures accurate navigation and prevents potential collisions with obstacles or other aircraft. Declination refers to the difference between magnetic north and true north, varying by location and latitude. Ignoring declination can lead to significant navigation errors.
Importance of Declination in Navigation
Declination is a crucial factor in navigation, particularly for pilots who rely on magnetic compasses for orientation. A magnetic compass points towards the Earth’s magnetic north pole, which is not the same as true north. The difference between the two is known as declination, and it varies depending on the location and latitude. For example, in the United States, the declination ranges from 9 to 20 degrees east, while in other countries, it can be much larger.
Calculating Declination
To accurately navigate, pilots need to know the local declination. There are several ways to determine declination, including using a declination chart or an app that provides real-time declination values. The US Naval Observatory provides a free declination chart that can be downloaded and printed. For example, if a pilot is flying near 35°N latitude, they would look up the declination for that location, which might be 10.5° east.
Adjusting for Declination
Once a pilot knows the local declination, they can adjust their magnetic compass to obtain a true bearing. This is typically done by adjusting the compass dial by the amount of declination. For example, if a pilot needs to fly a bearing of 270° true, and the declination is 10.5° east, they would set their magnetic compass to 259.5° to account for the declination.
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