## Variation See [[Magnetic Variation]] --- ## Deviation See [[Magnetic Deviation]] --- ## Dip Errors > [!summary] From [[PHAK Ch8]] > The Earth's magnetic field runs parallel to its surface only at the Magnetic Equator, which is the point halfway between the Magnetic North and South Poles. As you move away from the Magnetic Equator towards the magnetic poles, the angle created by the vertical pull of the Earth's magnetic field in relation to the Earth’s surface increases gradually. This angle is known as the dip angle. > ... > If the compass needle were mounted so that it could pivot freely in three dimensions, it would align itself with the magnetic field, pointing up or down at the dip angle in the direction of local Magnetic North. > > ### Acceleration Errors > [!summary] From [[PHAK Ch8]] > The magnetic dip and the forces of inertia cause magnetic compass errors when accelerating and decelerating on easterly and westerly headings. Useful Mnemonics: [[ANDS]], [[UNOS]] > [!youtube] From [[Aviation Theory]] >  ### Turning Errors > [!summary] From [[PHAK Ch8]] > The center of gravity of the float assembly is located lower than the pivotal point. As the aircraft turns, the force that results from the magnetic dip causes the float assembly to swing in the same direction that the float turns. Useful Mnemonics: [[NOSE]] > [!quote] From [[Flight and Ground Instructor Pro-Tips]]: *Molasses in the Compass* by Andrew Godfrey > I shared how I think of the fluid in the compass as molasses instead of a "[[Whiskey Compass]]" where on a northern heading, the molasses is thick, and the compass lags behind. The molasses is like warm syrup on a southern heading and leads the heading. > [!youtube] Published by [[Aviation Theory]] >  --- ## Additional Errors - Beyond approximately 18° bank, the jewel-and-pivot type mounting can't rotate freely and may be unpredictable. --- ## Resources - [[PHAK Ch8]] - [[Magnetic Dip]] - [If You're A Pilot, This Is What You Need To Know About Your Magnetic Compass](https://www.boldmethod.com/blog/learn-to-fly/aircraft-systems/how-your-magnetic-compass-works/) from [[Bold Method]]