Certified Flight Instructor - Flight Instructor Airplane Practice Exam

Which statement is true about magnetic deviation of a compass?

1. Deviation is the same for all aircraft in the same locality.

2. Deviation varies for different headings of the same aircraft.

3. Deviation is consistent across various aircraft in different localities.

4. Deviation remains constant regardless of magnetic interference.

The correct answer is: Deviation varies for different headings of the same aircraft.

The statement about magnetic deviation of a compass that is true is that deviation varies for different headings of the same aircraft. Deviation occurs due to magnetic fields generated by the aircraft itself and its equipment. Different headings can cause varying levels of interference, leading to different degrees of deviation at different orientations. This means that the compass reading can be affected by the plane's own magnetic environment, which is not uniform across all headings. While other options suggest uniformity—for instance, claiming deviation is the same for all aircraft in the same locality or across various aircraft—this is incorrect because each aircraft has its own unique magnetic environment influenced by its materials and equipment. Additionally, stating that deviation remains constant regardless of magnetic interference ignores the fundamental nature of deviation, which is inherently variable based on the heading of the aircraft. Understanding this principle is crucial for pilots when interpreting compass information accurately during flight.