What is the difference between magnetic north and true north, and how do you convert between them?

What is the difference between magnetic north and true north, and how do you convert between them?

• A. Magnetic north toward a magnetic pole; true north is geographic; conversion uses magnetic variation (declination).
• B. Magnetic north and true north are the same.
• C. True north is magnetic; magnetic north is geographic.
• D. They differ only in pilot preference and wind.

Answer: (A)

The key idea is that magnetic north and true north point to different places. True north is toward the geographic North Pole, fixed by the Earth’s axis. Magnetic north points toward the Earth's magnetic pole, which moves over time as the Earth's magnetic field changes. The difference between them is called magnetic variation (declination). To move between true and magnetic headings, you apply this variation. If the variation is east, you add it to the true heading to get the magnetic heading. If the variation is west, you subtract it. When converting the other way, you subtract east variation or add west variation. In practice, you pull the current magnetic variation from aeronautical charts for your area because it changes slowly over time and with location. This variation is what lets you translate between a true north reference and the magnetic compass reference used in flight.

The key idea is that magnetic north and true north point to different places. True north is toward the geographic North Pole, fixed by the Earth’s axis. Magnetic north points toward the Earth's magnetic pole, which moves over time as the Earth's magnetic field changes.

The difference between them is called magnetic variation (declination). To move between true and magnetic headings, you apply this variation. If the variation is east, you add it to the true heading to get the magnetic heading. If the variation is west, you subtract it. When converting the other way, you subtract east variation or add west variation.

In practice, you pull the current magnetic variation from aeronautical charts for your area because it changes slowly over time and with location. This variation is what lets you translate between a true north reference and the magnetic compass reference used in flight.