Hi,I used to manually calculate my own flightplans and compare the bearings with the MS-Flightplanner of MS FS2000 & FS 2002.I calculated the varition free great circle bearings and then tried to figure outthe local mag var's of about 100 airports of my concern by putting in various legs from the airports VOR to some other VORs and compared the FS 2000/2002 given bearings with the 0 mag var bearing. This gave me some reliable values for the local mag var. In some cases such as Seattle KSEA where the runway 34R geometrically is almost exactly in North direction, the given bearing of 340 degrees indicates a mag var of -20 ( exactly -20.2). But now I have downloaded A. Antonini's Super Flightplanner which allows direct read out of the mag var values of any given point on earth as they are stored in the FS2002 database. And here I get lost, because for instance in case of Seattle it tells me -17.9 degrees variation. Accordingly Antonini's Calculator gives for instance a bearing of 105.3 degrees for SEA-YKM ( Yakima)which is based on -17.9, while MS FS2002 gives 103 degrees which is consistent with -20 degress. What is correct? Anybody can help to sort out the discrepancy?Ceepee

The difference may depend on the magnetic model being used also the magnetic year.For Fsbuild which uses that LGRF WMM model for the year 2000 the variation for Seattle is -19.0, but the same model for the year 2002 its -18.0 the same as SFP has (I suspect SFP is using the same model).Perhaps the FS2002 magvar model goes back earlier than the year 2000or maybe MS is just using as different magvar model.Regards.Ernie.