COMPASS HEADINGS.

[SG-19]

Hi all, here's a teaser for you. Sometimes, not always i'll start up FS9 load up a flight at random and any aircraft from my vast hanger, only to find that when correctly lined up on the runway ie 25 at egxc which should read 255 degree's, I find my compass heading can be off by as much as 5 - 25 degrees, yes I do tap D to reset the directional indicator, but with no success. Any help or idea's out there would be appreciated.

[c130lover]

I think that flight simulator runway numbers are based off of the true heading (degrees from true north) and your compass is based off of magnetic north. Correct me if I'm wrong. I'm pretty sure runways IRL are magnetic because I remember a couple airports changing runway numbers a while back.

[Hawkeye07]

And if I remember correctly runway numbers are rounded off to the nearest 10 so a mag heading for a particular runway might be 255 but the runway number will be 25 as in 250.

[beaky]

Runways are aligned with magnetic morth in FS9, as in real life. The reason is that the earths magnetic field and geographic grid are not aligned... the magnetic poles are not aligned with the geographic poles, and the isogonic lines are pretty wiggly. In some places, true north and mag north can be off by almost 90 degrees!
The headings are rounded up or down to the nearest multiple of 10.
In real life, the isogonic lines also actually drift over time, a little here, a lot there...causing some runway headings to be off by quite a bit eventually... but I'm not sure if that is represented in FS9 (as in known compass deviations ca 2004).
But in the case of the airport mentioned, a big factor is that Rwy 25 should be headed at 250, not 255.

[Fozzer]

Living very close to the Greenwich Meridian my journeys on my Motor-bike are very simple Compass headings, UP = North, Down = South, with East and West in between.
But my daily sojourns on the USA Pacific Coast are entirely different!
Looking on my Map, my journey from Los Angeles to San Francisco should take me; "UP", ie; Northwards...
But no....I have to set a course Westwards!
...and going from San Francisco to Los Angeles, ie; "DOWN", sets me on a course Eastwards!
North is no longer up, and down is no longer South!
The further I travel UP the coast, the more "North" gets shifted Eastwards!
I find compass headings on the Pacific Coast very confusing. Its a strange feeling!
I have very little faith in the needle in my Compass!... ... ...!

Paul....encompassed in needles... ...!

[SG-19]

Yes I understand about how runway headings are marked, but I think you are misunderstanding my point or I misdiscribed it. As I have already explained in my first post, when I start up FS9 and position my aircraft on the runway any runway or any aircraft, my compass should read in relation to the runway heading ie at EGXC rnwy 25 should read on a digital compass as 255 degrees, mine however can read as much as 280 degrees. Even when i'm in flight it does not correct in any way. In effect it's like having a magnet stuck to the side off the compass giving a false reading. I don't seem to have this problem every time I start up just periodically, It's just puzzling.

[garymbuska]

I have been in at least one airport in every state in the US and it is rare to find a runway number that is exactly the same as the heading a good example is at KJAX (Jacksonville, Florida) runway 26 is not on a heading of 260 degrees it is
257 magnetic, 251 true
You have to remember that the magnetic variation for FS9 is very old and should be updated.
There are several web sites that will tell you everything about any runway. I use http://www.airnav.com/
but this is only for US airports but this is a VALID FAA site and the information is accurate
I just discovered that the runway numbers for KJAX just changed they used to be 7/25 and 13/31 and are now 8/26 and 14/32
I had to look twice as this is my home airport and used to work there so it kind of caught me with my pants down.
Now I will have to go and update the runway.
I use to fly for DELTA virtual and one of the goals was to land and take off at 1 airport in every state. This was a little tricky as I had to use actual flights to each airport so that meant I had to use some airports more than once in order to land at each airport in every state.

[investdude]

SG-19

This is a known problem. Its caused by your magdec.bgl file becoming corrupted. To fix it you need to copy the magdec.bgl file from your disc to C://Program Files/Microsoft Games/Flight Simulator 9/Scenery/BASE/Scenery and overwrite the old corrupted file.