True vs Magnetic headings...

I know this topic has been discussed before, but never has the answer been satisfactory (to me) or a solution (that I know of) been provided.

 

Recently, I noticed that the aircraft heading on the active runway at KMVY indicated 221 degrees. The runwar is 236 degrees magnetic and the magnetic variation at KMVY is between 14 and 15 degrees. So far the math adds up, FS9 is giving me true headings! Sitting in the cockpit, I look at the following gauges that provide direction information. 1.) Magnetic compas = 221 degrees. 2.) HSI heading indicator when adjusted to the direction of the runway = 221 degrees.

 

It seems to me that FS9 magnetic compases should read, as all other magnetic compases do, magnetic bearings, which when facing down runway 24 at KMVY is 236 degrees. Something is FUBAR and I would verymuch like to un-FUBAR the situation.

 

Can anybody a.) offer an explanation as to how and/or why this change has occured, and b.) offer a simple fix that will not require deleting files and/or re-installing FS9?

 

Thanks for your help!

Where did you find the rw is 236 magnetic?

 

Both gauges indicate 221mag, are you sure the 236 is not 236 true?

It sounds like something has messed with your magdec file. Have you recently installed any addon scenery, if so disable it and test.? Incorrectly prepared scenery can cause this kind of problem.

Not so long ago I had the same problem at many airports around the world. Problem was caused by errors in addon airport scenery and not in the magdec file. In my case trial and error methods were necessary by de-activating / re-activating groups of addon sceneries via the scenery library and then testing the problem inbetween.

When the culprit scenery is found you could have a go at finding the responsible bgl file via the same trial and error method and then delete it. However, this could cause some scenery objects to disappear as well. In my case it was necessary to delete the whole addon airport.

 

Good luck

Hans

Sitting on the active runway 24 at KMVY I was reading 236 on both magnetic compass and heading indicator.

 

This is from the real world airport.

 

Runway 6............ ..................RUNWAY 24

Latitude: 41-23.199302N .........41-23.887307N

Longitude: 070-37.160042W .....070-36.376588W

Elevation: 53.7 ft. ...................62.7 ft.

Gradient: 0.2%................. ......0.2%

Traffic pattern: left........... ......right

Runway heading: 056 magnetic,..236 magnetic, 221 true

041 true

I doubt that scenery is the issue; the only recent adds are U.T., FS Genesis, and G.E. No airports or other odd-ball add-ons. Zippy's instruments are providing proper readings. He has also provided data on KMVY from the real world, although the FS9 data is very similar if you check out the airport.

 

My magnetic compas is not a magnetic compas at all, it's a "true reading compas." Need to figure out how to fix it!

It is almost certainly due to addon scenery, even scenery you installed long ago can have unexpected interactions with a specific location or recent scenery additions.

 

But if you want to just ignore the bad scenery and use a workaround:

 

1. Create a new folder in the Addon Scenery folder called something like MagDec Fix

 

2. Create a new folder called scenery inside that one.

 

3. Move the magdec.bgl file from its default location in FS\Scenery\BASE\scenery to your new scenery subfolder.

 

4. Start FS and open the Scenery Library. Add the MagDec Fix folder as a new layer right at the top of the list.

 

5. Restart FS and check the runway headings.

 

Hope this helps,

Sitting on the active runway 24 at KMVY I was reading 236 on both magnetic compass and heading indicator.

 

This is from the real world airport.

 

Runway 6............ ..................RUNWAY 24

Latitude: 41-23.199302N .........41-23.887307N

Longitude: 070-37.160042W .....070-36.376588W

Elevation: 53.7 ft. ...................62.7 ft.

Gradient: 0.2%................. ......0.2%

Traffic pattern: left........... ......right

Runway heading: 056 magnetic,..236 magnetic, 221 true

041 true

 

 

That's bad! But now they're starting to change the painted numbers on the runways to true headings as well! Confusing to a non-local? Like you wouldn't believe!

Tom, Thanks for the fix! We are back to normal now, thanks to you, much appreciated my friend.

Glad to help. :)

Tom, I thank you also! The issue reared its ugly head and was bugging the heck out of me. Sanity and peace of mind have been restored, and all is right again in my FS world.

I just throw this in as an interesting and irrelevant fact. Canadian runway headings in the Northern Domestic Airspace (you can find a map showing where this is) are quoted as true headings instead of magnetic, as magnetic compasses are so unreliable in this area that they are unusable.

Tom, I discovered that while moving the FS9 magnetic heading bgl to the top of the library list solves the problems when flying, it puzzles a scenery making programme like SceneryGenX when it looks in the expected location and finds that FS9 no longer believes in the wandering magnetic north!

There's no reason it cannot be in both the default location and at the top of the listing. Just copy and paste it.

Tom, I already did, but that puzzled me for 20 minutes!