I'm running the latest airac 0813 and finding that the pmdg is not tracking on the purple line. The Gaugeis showing a heading of 165 and the fmc showing 156 to Dunno. I have uninstall the latest airac 0813 andre-install it and still have the problem. This flight from NZAA to NZWN via NP VOR, the aircraft tracks likethis all the way to NZWN. When it loc onto the ILS of the runway 34 it not on the purple line or the centre linebut to the left of the purple line had to disenage the auto pilot and manual bring it in.Any reason why it doing this.I use flight slim 9Regards,Ray Lang

Im not sure if it matters, but the lastest AIRAC is now 0901. If this has only happened since the latest AIRAC update that you installed, you may want to consider updating your AIRAC to reflect the current 0901 to see if that helps any.

I don't think this is a navdata problem. Tracking errors are usually due to either 1) registry error or 2) addon scenery corrupting the magnetic deviation internally in MSFS.I recommend first trying to fix the possible registry problem. There is a registry repair tool available at Flight One (it's free and has been reported to work numerous times in this forum).By the way the ND is showing a TRK of 156 (not HDG) which is the bearing to next fix according to the progress page shown on the CDU. This is not an error.

Thanks to downscc in mention in his post "magnetic deviation", as I thought it was strangethat it affected all payware aircraft.I went thru MSFS folders and loacated a msfs airac file in the fs9 folder move it out of thereand loaded up a flight sure enough the aircraft was tracking on the purple line and ILS approachesright down the centre.Thanks to all who have posted especially downscc one very happy pilot.Regards,Ray Lang

could you please tell us what was the name of the file and where it was located?? (what folder/subfolder???) thanks in advance.

I have searched the forum to find an answer to why my PMDG 747 is 4-5 degrees out when it lands. Almost 1,000 hours of trouble-free flying with PMDG aircraft and then...................this problem started.1. Have done the registry fix thing.2. Disabled 3rd party scenery software and rid myself of all AFCADs.3. deleted and reinstalled PMDG aircraft.4. I don't have any other 3rd party aircraft.Maybe I have to delete FSX and start all over???regards,Chris White

First thing to try is registry repair using the Flight1 free and safe utility.EDIT: Two min. search found this: FS9 puts magdeviation in a file called magdec.bgl in the \Scenery\BASE folder. If it is modified or corrupt it can cause problems with localizers and tracking a course. My original is datetime 3/3/2003 size 127kb. Not sure what FSX uses.. haven't had the same problems.

Used the Flight1 Registry repair. Does not produce a sustained result.I have not found the FSX equivalent of the magdev file.regards,Chris White

Used the Flight1 Registry repair. Does not produce a sustained result.I have not found the FSX equivalent of the magdev file.regards,Chris W

Hey Chris the file that you seek is called magdec.bgl and its in the scenery/base/scenery folder. However Im not sure the consequences of removing it.Ian

Ian,Thanks for that. Found it, changed it...no difference...back to drawing board.regards,Chris