Which term describes the error of a magnetic compass caused by magnetic fields in the aircraft and other metal components?

Which term describes the error of a magnetic compass caused by magnetic fields in the aircraft and other metal components?

• A. True heading error
• B. Dip error
• C. Deviation
• D. Variation

Answer: (C)

The main idea here is understanding where compass errors come from. A magnetic compass can be off for two broad reasons: the Earth's magnetic field itself, which makes magnetic north differ from true north, and local magnetic influences inside the aircraft caused by its metal structure and equipment. The error produced specifically by those aircraft-related magnetic fields is called deviation. Pilots use a deviation card to correct the compass reading so it reflects the true magnetic heading, and then they apply local variation to reach the true heading. This is different from variation, which is the angle between true north and magnetic north at a given location on the Earth, not caused by the aircraft. Dip error relates to the vertical component of the Earth’s magnetic field and is a separate phenomenon, not produced by the aircraft’s own metals. So the term describing the error due to magnetic fields in the aircraft and metal components is deviation.

The main idea here is understanding where compass errors come from. A magnetic compass can be off for two broad reasons: the Earth's magnetic field itself, which makes magnetic north differ from true north, and local magnetic influences inside the aircraft caused by its metal structure and equipment. The error produced specifically by those aircraft-related magnetic fields is called deviation. Pilots use a deviation card to correct the compass reading so it reflects the true magnetic heading, and then they apply local variation to reach the true heading.

This is different from variation, which is the angle between true north and magnetic north at a given location on the Earth, not caused by the aircraft. Dip error relates to the vertical component of the Earth’s magnetic field and is a separate phenomenon, not produced by the aircraft’s own metals. So the term describing the error due to magnetic fields in the aircraft and metal components is deviation.