Why do we have dip-compensating weights in magnetic compasses?

Magnetic Compass is the most primal and basic instruments used by the pilot to determine or verify aircraft heading. A graduated scale, called a card, is wrapped around the float and viewed through a glass window with a lubber line across it. read more

Commercial aircraft will have 2 gyro stabilized compass systems, and when one is in the areas of magnetic unreliability in the far north and south, the flux valve or the spirit compass is useless and the gyros may precess up to a degree a minute in turbulence or approach manoeuvres. read more

Photo: Magnetic compasses are really easy to use, but it helps if you have a map as well so you know which direction is best to head for. Photo by Dominique M. Lasco courtesy of US Navy. Compasses you buy are a bit more sophisticated than floating needles but work essentially the same way. read more