Which of the following conditions can make a magnetic compass inaccurate?

A magnetic compass can become inaccurate due to a variety of physical factors affecting its ability to align with the Earth's magnetic field. Making a steep turn is one of the key conditions that can lead to compass inaccuracies due to the phenomenon known as "magnetic dip" or the "compass card dipping."

When an aircraft banks during a turn, the compass card is also tilted. This causes the compass to behave erratically as it is no longer oriented directly parallel to the Earth's magnetic field lines. Instead, it might indicate a turn in the opposite direction or show excessive lead or lag indicators. Therefore, the relationship between the aircraft's heading and the compass reading can become misaligned during a steep turn, leading to inaccuracies in navigation.

Understanding this principle is crucial for pilots as it highlights the importance of using other navigational aids in conjunction with a magnetic compass, especially in turns or when operating at different flight attitudes.