Final answer:
In aircraft navigation, a magnetic compass can be affected by the Earth's magnetic anomalies, the aircraft's own magnetic fields, and in regions of vertical magnetic fields, which cause the compass needle to behave unpredictably. The compass issues, including magnetic dip and other interferences, must be considered for accurate navigation.
Step-by-step explanation:
The issues with a magnetic compass in an aircraft that have to be considered in navigational plotting are influenced by the Earth's magnetic field variations and distortions caused by the aircraft's structure and electrical systems. At the equator, flying due west, a compass needle should, in theory, point north, staying perpendicular to the direction of motion if the magnetic and geographic poles were aligned. However, in reality, the orientation of the compass needle may change due to local magnetic anomalies or aircraft-induced magnetic fields, leading to a deviation from the expected direction.
In regions where the magnetic field is nearly perpendicular to the Earth's surface, a compass can become unreliable or difficult to read because the needle may dip or even flip vertically rather than aligning horizontally to point north-south. This problem is known as magnetic dip. Furthermore, when an aircraft acquires a static charge, as in the case of a jet flying over the magnetic pole, there can be a magnetic force acting upon the craft due to interaction with the Earth's magnetic field, although this effect is typically negligible for navigation purposes.