What is the primary cause of magnetic compass errors during turns, accelerations, and decelerations?

The primary cause of magnetic compass errors during turns, accelerations, and decelerations is magnetic dip. Magnetic dip refers to the angle at which the Earth's magnetic field lines intersect the surface of the Earth, which changes depending on your geographic location. As an aircraft turns, the compass may lag behind due to the inertia of the liquid within it, resulting in a false reading—this is referred to as "oscillation."

Moreover, during accelerations, the compass may show a turn towards the north, and during decelerations, it shows a turn towards the south. This behavior is directly influenced by the magnetic dip, as the compass's needle can be affected at different latitudes due to the tilt of the magnetic field lines relative to the Earth's surface. Therefore, understanding magnetic dip is crucial for accurate navigation and for pilots to interpret compass readings correctly under varying flight conditions.