Compass Use

The magnetic compass is the primary navigation aid in most light aeroplanes and the only instrument that directly shows the correct heading.

When using the magnetic compass for navigation, there are several considerations beyond simple turning errors.

The magnetic compass can show several errors, so the pilot must be able to accurately turn onto and maintain a desired compass heading.

Understanding the causes of compass errors is less important than knowing how to compensate for them in flight. A basic awareness of these errors is sufficient for safe navigation.

Objective

To accurately turn onto and maintain compass headings while compensating for known magnetic compass errors.

Considerations

Variation

The Earth has a geographical (true) North Pole and a geographical (true) South Pole.

A magnetic field surrounds the Earth, created by the equivalent of a very large bar magnet within its core. This produces a magnetic North Pole and a magnetic South Pole (see Figure 1).

The magnetic poles are not located at the same points as the true poles; however, they are currently close enough to allow the use of magnets for global navigation.