Magnetic headings True headings

[kehoshi 1]

I am in the process of developing with ADE from the FSX stock EDDC airport a new one to comply with the latest Jepperson Files and AIRAC.

I see from the Runway Properties in ADE that the Heading (from Base End) is 40.87 True and the ILS Properties for 04 is 40.87 True and for 22 is 220.87 True.

In the Jepperson Charts, and I presume also in the latest AIRAC these headings are for RWY04 39 Degrees and for RWY22 219 Degrees.

My question is:- should I change these headings from those quoted in the stock airport to those indicated in the Jepperson Charts and also what is the difference between True and Magnetic headings and what, if any, part do they play in FSX.

Sorry if this is a dumb question but my grey matter is in this case a little grey.

[OldFlyboy 30]

True heading is the actual course you wish to fly.Mag heading is the compass reading you use to adjust for the earth's magnetic variation.

The Magnetic North :Pole is actually a considerable distance from the Actual North Pole. As a result, a compass reading will rarely be the same as true heading.

As an example: In northern Alaska if your plane is actually heading Due North  your compass will be reading somewhere between 250 and 270 degrees.

A flight plan course is calculated using T V M D C

True Hdg  +/-  Variation =Mag hdg  +/-   Deviation  = Compass Heading to use

[pschlute 37]

True Headings are referenced to true North, and will never change. Do not change the true headings in any airports.

 

Magnetic headings are referenced to magnetic North, which not only is not located near true North pole, but actually moves over time.  There is a file magdec (google magnetic declination) which tells your FSX how much to adjust the true heading by to arrive at a magnetic heading depending where you are in the world. You may encounter differences as the original magdec file is now many years out of date. Also the latest charts may show a difference between the magnetic heading of a runway and what you see in the sim. This can be due to the magdec file or the declination written into a specific scenery.

 

Most of the time you wont notice a difference of more than a few degrees. Just remember you are always flying to magnetic headings/course (with a very few exceptions)