Definition
The downward tilt of a magnetic compass needle caused by the vertical component of the Earth's magnetic field. Dip is most pronounced near the magnetic poles, where the field lines run nearly straight down into the Earth, and is negligible near the magnetic equator, where the field lines run roughly parallel to the surface.
Plain English
The Earth's magnetic field doesn't run flat across the surface — it angles into the ground, especially near the poles. This pulls one end of a compass needle downward. That downward tilt is called dip, and it's the root cause of several compass errors pilots have to account for.
Context Anchor
Seen in magnetic compass discussions, especially when learning why a compass can show errors during aircraft movement.
Derivation
From the Old English 'dyppan,' meaning to plunge or lower into. The word is used in its plain physical sense here: the needle dips, or tilts downward, toward the Earth.
Why Pilots Care
Pilots must compensate for dip-induced errors to maintain accurate headings, especially at higher latitudes.
Grounding Statement
Picture the magnetic field not as a flat line across the earth, but as a line that leans downward into the ground in some areas.
Intuition Check
Dip does not mean the airplane briefly drops. Here it means the tilt of Earth’s magnetic field, which can affect a magnetic compass.
Example Sentence 1
Compass dip is why the magnetic compass leads or lags during turns through north and south.
Example Sentence 2
During preflight planning the instructor explained how dip affects compass accuracy at higher latitudes.