King Air 2nd Navigation display twice applies magnetic variation.

  • The route displayed in the map shows about 26 degrees of magnetic variation. The outer scale is normal but the displayed route is canted wildly clockwise. This route is 003 degrees true track, 350 degrees magnetic track and the runway magnetic heading is 348 degrees. The track on the right side resembles a chart of an area with about 26 degrees of East Variation. The local variation is 13 east. I was obviously unable to check how it would look in Switzerland which has zero to 1degree East.



    The other glass cockpit planes look OK.

    (2019, iOS FS2 and Android beta FS2 version 2.5.17 AND PC FS2)

  • Variation is the difference between true north, the direction of the north pole and where the compass needle points which varies greatly across the world. Here is the north west of the Aerofly mobile scenery where the compass angle difference is highest. The route shown is almost true north, 359 degrees but because the compass points 17 degrees east of true north, in order to fly the route using the Aerofly planes a magnetic heading of 359 minus 17 degrees must be flown assuming no wind. This SkyVector chart shows the 359-17 or 342 degrees heading.

    The * boxes show the compass needle bearings relative to the navigation beacons, 17 degrees of east variation.

    Aerofly routes use the correct magnetic variation automatically.


    In the Swiss scenery the planes can fly more or less directly, the magnetic variation is on average less than a degree.


  • The route displayed in the map shows about 26 degrees of magnetic variation. The outer scale is normal but the displayed route is canted wildly clockwise. This route is 003 degrees true track, 350 degrees magnetic track and the runway magnetic heading is 348 degrees. The track on the right side resembles a chart of an area with about 26 degrees of East Variation. The local variation is 13 east. I was obviously unable to check how it would look in Switzerland which has zero to 1degree East.



    The other glass cockpit planes look OK.

    (2019, iOS FS2 and Android beta FS2 version 2.5.17 AND PC FS2)

    Very good catch!

    I plan to change the EFIS of the C90 eventually anyway so this is just one more thing to check on a long list.

    As you can see the flight plan line goes across the PFD, too, this should never be the case. Also I would love to bring the EFIS to live, I want to have different modes like rose, arc, I want the menus and the other great features :) But one thing at a time.

    The double magnetic deviation should be an easy fix.

  • Overloaded

    Changed the title of the thread from “King Air 2nd Navigation display applies double magnetic variation.” to “King Air 2nd Navigation display twice applies magnetic variation.”.
  • Thanks Jan. I changed the title as I got myself in circles!, I don’t know what is really going on.

    The second display is 13 degrees off the centre display but it is in fact showing 13 degrees higher and I got myself a bit mixed up (this resembles converting easterly variation magnetic back into true).

    360 true minus 13 East gives 347 magnetic which would be displayed for a true track of north. The right display seems to show north instead of 347 but when trying to fly that route as displayed on the right the plane will track 13 degrees east of the ‘apparent route’ as displayed.


    The plane is in fact tracking ‘apparent magnetic north’ (based on the displayed route and index) plus the magnetic variation which is how I got my “double applied variation”.

    The right display sort of resembles heading true on the outer index and ‘apparent track’ true displayed but with the magnetic track being flown as should be expected if the plane is actually flying on magnetic.

    Would this resemble selecting display true rather than magnetic on the right, in a flight management menu?