Magnetic variation updates for FS9 and FSX

[Guest jahman]

The real problem of course is we didn'y get FSXI 2 years after FSX was released. Cheers, - jahman.

[HiFly 16]

I find no problem using Herve's corrected magdec file but I have FSX not FS9 and I use a separate flight planner. All my mag headings and courses are now correct according to current RW charts. And BTW, FSX uses one magdec file in the "base" scenery folder which is what Herve is replacing with his download. That affects the entire simulation. The problem, I state again, is that though the listings in the FSX map for individual airports reflect most changes I make through Design Editor, they do not cprrect the ILS course display data even after I update the variation coding in the individual airport through Design Editor. The ILS itself is actually corrected, but the data in the menu file still displays the old values. FMC will use those old values when you select an ILS instead of the current navdata installed in FMC's database. The workaround is simply to enter the correct course for the navaid in the MCP manually and not allow FMC to automatically set it for you. The plane will then fly the correct course even on IAN VOR/LOC-BC approaches. With the updated magdec it goes without saying that you must use current RW charts. Oftimes what can be downloaded from the internet are charts that date back into the 90's. We all must carefully check the publication date or we are headed for inconsistencies. Oh, and BTW, I have never heard of nor experienced any CTD caused by incorrect position of waypoints in a flight plan. Only thing that will happen is FSX will end up flying an offtrack course instead of correctly tracking along the airway!

[Guest jahman]

Make sure you all contact MS Flight and ask them to fix this by implementing and updateable magvar BGL file and airport runways and SIDs/STARs that self-name according to their geographic heading and current magvar when the magvar file is updated. Cheers, - jahman.

[scott967 62]

Note that the function of magdec.bgl is to control how the magnetic compass, weather info (wind direction) and windsocks function (or other objects which can rotate to the wind). Note also that for VORs, magnetic north is set by the agency controlling the aid. Magnetic north, as set on a VOR probably is NOT the same exact direction as shown on a magnetic compass. You have to find source data that show what the mag var is set to for each VOR. This of course controls what the radials from the VOR are. In general in the US, FAA only uses magvar from 5-year intervals (i.e., 2005, 2010, 2015) but even then, they won't just go through and move all the VOR settings at every interval; only when they think it is necessary. For localizers and charts, localizers have no need for magvar, the geometry of the antenna controls the approach course. FAA and other agencies will update charts, but again it is based on the 5 year interval and need. Note that in NE Canada, magnetic is not used for charts nor VORs. These are set to true and you see course indications such as 130T on charts. Given the data, it is possible to update the default VOR data. I think replacing the default files is best for this case. I remember someone was doing this for Alaska (FAA has changed many VORs there) but lost track of the status of this project. OT but related, China is in the process of updating all their data to WGS84, by FIR. I believe all the China data in FSX is misplaced (my guess -- MS took the positions of all the China data and assumed it was WGS84 but that isn't the case). You can check this in Google Earth and see that positions are often off by 100s meters in FSX. scott s..

[rototom 198]

The runway mag heading is a fixed value based on the true heading. The only way to change runway mag heading is to change true heading and that will then misalign the physical runway.

Can you clarify this? Magnetic north is not fixed, so how can runway magnetic be fixed? I have seen runways get new numbers several times becuase the magnetic heading changed. When magnetic variations change the magnetic heading changes and that should be the same for runways.

[Pete Dowson 558]

Can you clarify this? Magnetic north is not fixed, so how can runway magnetic be fixed? I have seen runways get new numbers several times becuase the magnetic heading changed. When magnetic variations change the magnetic heading changes and that should be the same for runways.

Runway magnetic headings change, but the runways don't move. The important navaids -- localiser and glideslope -- are aligned with the runway on the ground, independently of magnetic north, and will work without changes needed. When the numbers change you would need an AFD BGL update for the writing on the taxiway signs, and on the runway threshold, and of course you should get updated charts so you set your CRS and HDG bugs appropriately. But that's all.RegardsPete

[rototom 198]

Runway magnetic headings change, but the runways don't move. The important navaids -- localiser and glideslope -- are aligned with the runway on the ground, independently of magnetic north, and will work without changes needed. When the numbers change you would need an AFD BGL update for the writing on the taxiway signs, and on the runway threshold, and of course you should get updated charts so you set your CRS and HDG bugs appropriately. But that's all.RegardsPete

Yes, I understand that. I was just asking for clarification on the statment "The only way to change runway mag heading is to change true heading". As stated, it is not correct.

[hervesors 1]

Pete is right..Runway true heading is an invariant parameter and ILS LOC deviation still works the same whatever the magnetic variation is (GS is not affected though)..but your current FS displayed magnetic track will not fit the approach course (magnetic) if magnetic variation is a way "out". Taxiway signs and runway markings is another problem that has to be corrected another way (scenery edition)RegardsHervé

[Barbs 2]

Does anyone know of where we can get this now? The link in the OP is broke. :(