# Questions tagged [magnetic-variation]

Questions about the difference between magnetic north and true north, which various based on geographic location

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### Where do I land if I fly from KLAX with a constant east heading, crossing the US and the Atlantic ocean?

Los Angeles KLAX and Casablanca GMMN (Morocco) are at the same latitude. If the aircraft follows a magnetic 090° heading, the initial true heading will be 102° due to the declination. (source ...
70k views

### When are winds given with respect to true vs. magnetic north?

Wind information can be reported by various sources (ATIS, METAR, TAF, spoken on the radio, etc). I was taught that officially some of these sources are relative to magnetic north and others to true ...
117k views

### What's the difference between True vs Magnetic headings?

What is the difference between a true and a magnetic heading? Why are/were magnetic headings used in aviation?
11k views

### How do airports determine when they should change their runway numbers?

Runway numbers in most of the world are based on the runway's orientation relative to magnetic north. For example a runway with a magnetic heading of 135° to 144° will be numbered ...
23k views

### How do I convert true heading to magnetic heading or the other way around?

Is there a method by which the conversions can be achieved on the fly by using a mathematical formulae and not using specific area charts?
4k views

### Why does this chart seem to show airports with magnetic variation up to 90 degrees?

I am trying to understand some plots of the earth's magnetic variation (declination) by trying to correlate what I see in a figure like the one below with the variation reported for some airports. I'm ...
204 views

### How often, and how promptly, do airports have to renumber runways because of magnetic pole drift? [duplicate]

This question was prompted by this answer to another question by Jamiec. As the magnetic poles drift (usually pretty unpredictably), runway numbers become inaccurate. As noted in the linked answer, ...
2k views

### Why do METARs report wind relative to true north rather than magnetic?

Why isn't the wind in a METAR given in magnetic heading, to match the runway numbers? Especially for areas where there is a double-digit magnetic declination. Secondary/optional question: does the ...
811 views

### Is my understanding of magnetic variation and declination (for a VOR) correct?

AIXM (the XML-based exchange model for AIP by Eurocontrol and european AIS) defines the following properties for a VOR: codeTypeNorthA code indicating the ...
2k views

### Is this the correct sequence of steps to convert from true course to compass heading?

I wanted to confirm my understanding of VFR Flight Planning/Dead Reckoning with relation to heading and course calculation. Is the below correct? Using a plotter, draw a line from departure airport ...
93 views

### What official government document should a pilot check to determine what magnetic north a VOR was set to when it was commissioned?

Today I learned that VOR stations are all set to magnetic north at the time of commission, and since magnetic north moves, the VOR is not necessarily in-line with magnetic north in the present. Where ...
175 views

### Are artificial magnetic fields used or proposed to be used to shield high altitude pilots and astronauts from charged, high energy radiation?

If not for the earth's magnetic field our atmosphere would be bombarded by high energy plasma (ionized gas) from the sun and other space sources. At very high altitudes and orbital altitudes this ...
138 views

### Why do both east and west isogonic lines tilt toward the west as they go north?

Here is a picture of the 3 degree east isogonic line just north of Tulsa, OK. Here is a picture of the 4 degree west isogonic line just east of Nashville, TN. They both trend westward in relation to ...
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### Do I use true or magnetic north in headwind component calculations? [duplicate]

For the landing performance calculations, I want to calculate the headwind component. I can do this with the runway heading and the reported wind direction and speed. But do I need to make any ...
498 views

### What course should be taken to make estimated calculations?

(skyvector.com) When I want to calculate the leg time from GIJ to CRL going along the airway J554, at say FL190, I know that I have to calculate the ground speed first, but in order to do that, ...
98 views

### Is airport's magnetic variation value used for terminal procedure design?

I am studying how instrument flight procedures are coded to ARINC-424 format, and since I was curious about the method used to determine the outbound/inbound magnetic courses, I checked the section ...
146 views

### How can I use a magnetic declination chart to calculate true track, magnetic track and magnetic variation?

If I am given values such as 30 degrees south and 75 degrees east with a true track value such as 70 degrees, how would I calculate the magnetic track? I understand that True track = Magnetic + ...
456 views

### Does the movement of the magnetic poles affect aviation?

Recently I read that Earth's magnetic pole moves quite significantly, several kilometers. Do these changes affect aviation, i.e. for pilots landing their airplanes?