What is the primary limitation of the magnetic compass?

The primary limitation of the magnetic compass is its tendency to lag during turns. When an aircraft enters a turn, the magnetic compass may not immediately reflect the change in heading because it relies on the laws of magnetism. As a result, the compass may show a gradual shift in heading, which can lead to misleading readings and affect navigation accuracy. This phenomenon is known as "compass lag," and pilots must be aware of it, especially during steep turns or rapid maneuvers, to avoid potential disorientation.

In contrast, the other options presented refer to situations that do not accurately describe the limitations of the magnetic compass. The compass operates independent of light conditions, so its functionality is not restricted to daylight. Although electrical systems in an aircraft can affect certain instruments, magnetic compasses are generally immune to electrical interference. Furthermore, the compass does not have limitations based on visibility conditions like clouds; it can be used in any weather scenario, provided the pilot can correctly interpret its readings. Knowing how to mitigate the compass lag during turns is crucial for maintaining accurate navigation.