# Does compass deviation vary with heading?

## Does compass deviation vary with heading?

Deviation is the amount by which the ship’s compass is affected by the characteristics of the vessel (such as the engine block and wiring / other ferrous metal objects, etc). Is the bearing a True bearing, Magnetic bearing or Compass bearing. All three may vary dependent on the vessel’s heading and position.

### Why does deviation change with heading?

The amount of variation slightly changes with time due to the slow migration of the Earth’s magnetic poles. The deviation also depends on the orientation of the ship within the earth magnetic field. Practically, the compass deviation depends on the heading of the ship.

#### What is magnetic heading deviation?

Magnetic Variation: The angular difference between true north and magnetic north. Also known as declination. Compass Heading: The aircraft’s magnetic heading corrected for deviation. The deviation is found on a compass card or a placard near the compass, and it usually varies by just a degree or two.

What is deviation and variation in navigation?

Variation is a magnetic interference common to all vessels. Deviation is a magnetic interference unique to the vessel itself. The deviation card tells you the boats error on different headings. As an example, this card tells us that there is a error of 2 degrees to the west when heading due north.

The heading of an aircraft, which is also referred to as bearing or vector, according to NASA, is the direction the aircraft is pointed in. For pilots, direction is always expressed in relation to due north on a compass and measured clockwise. Hence, north is 360 degrees, east is 90 degrees and south is 180 degrees.

Magnetic heading is your direction relative to magnetic north, read from your magnetic compass. True heading is your direction relative to true north, or the geographic north pole. The difference is due to the magnetic north pole and geographic north pole being hundreds of miles apart.

### How do airplane headings work?

#### What is the difference between magnetic variation and magnetic deviation?

The difference between true north and magnetic north is called magnetic declination or magnetic variation. Some sources also erroneously refer to it as magnetic deviation. It’s essential to take this phenomenon into account when navigating with a compass.

Do you add or subtract east variation?

The main thing to remember is whether to add or subtract variation and deviation. From true to compass add the degrees if they’re west (and subtract east), and from compass to true do the opposite; subtract west (and add east).

Is deviation and variation the same?

The variance is the average of the squared differences from the mean. Standard deviation is the square root of the variance so that the standard deviation would be about 3.03. Because of this squaring, the variance is no longer in the same unit of measurement as the original data.

## Do you add or subtract East variation?

### What is a 41 degree heading?

Working your way around clockwise from the top North is 0 (and 360), East is 90, South is 180, West is 270. So a heading of 41 is 41 degrees clockwise from north, putting it roughly northeast. Heading 341 lies between 270 and 360, so it’s roughly northwest.

#### What do you call deviation from a magnetic heading?

These errors are referred to as deviation. By adding or subtracting deviation from your magnetic heading this will give you a compass heading. A compass heading is the direction you could turn the aircraft to that has been corrected for winds, variation and deviation.

What’s the difference between a deviation and a variation?

Variation is a magnetic interference common to all vessels. Deviation is a magnetic interference unique to the vessel itself. We use the term ‘deviation’ use to describe the effect of interference from magnetic fields created by the vessel’s own equipment.

Which is an example of a deviation card?

The deviation card tells you the boats error on different headings. As an example, this card tells us that there is a error of 2 degrees to the west when heading due north. Whereas there is no error heading south. We calculate the deviation error in the same way as we do variation.

## How is the deviation of a boat calculated?

The overall effect of the vessels deviation can be calculated. It is recorded on something called a deviation card just like the one below. The deviation card tells you the boats error on different headings. As an example, this card tells us that there is a error of 2 degrees to the west when heading due north.