Introduction
PSX update 10.130 has introduced the option to load an external database file for the earth's magnetic field. When such a file exists in the Aerowinx/Terrain subfolder during simulator start, PSX will automatically load it and use it. If the file doesn't exist, PSX will use its internal magnetic field model from 2019.
The file must have a specific format and file name. The file can be generated on a special NOAA website and can be directly downloaded to the Aerowinx/Terrain subfolder. The process takes just a few seconds.
Where can I generate the file?
Here: https://www.ngdc.noaa.gov/geomag/calculators/magcalc.shtml#igrfgrid - The website looks like this:
(http://aerowinx.com/assets/pics/magvar01.jpg)
Note the yellow panel; this is your calculator. There you set some reference values before starting the calculator.
What values must be set?
The setting must look like this:
(http://aerowinx.com/assets/pics/magvar02.jpg)
Every field and checkbox must exactly be set as shown above, except for the following:
• You may select the WMM model or the IGRF model. I don't know which one is better. The differences are microscopically small. I recommend the IGRF model because the file will be smaller (the WMM file will include additional data that PSX won't read anyway).
• You can set the year, month, and day as you like. But the start date and end date must be equal! In the day fields I recommend to set 15; this assures the month display in PSX will not be rounded to the previous or next month.
Recheck that all settings are correct (89, 89, 1.0, 180, 179, 1.0, 0 etc. and the checkboxes S, N, W, E etc.). Then click the blue Calculate button below the yellow panel (not on this screenshot but on the actual NOAA website).
Where should the file be downloaded to?
When the Calculate button is clicked, your browser will pop up a window asking what you want to do with this file. Select "Save File", then click "OK" (the exact wording may vary from browser to browser).
Another window will open where you can select the file destination. Select your Aerowinx/Terrain folder. You can also select a different folder, for example, your Desktop, and after the download you can manually move the downloaded file from the Desktop to your Aerowinx/Terrain folder.
The calculator will name the file igrfgridData.csv. Don't change that name. By the way, the calculator will set this "igrf..." file name even if the WMM model has been selected.
Now click OK to start the calculation-and-download in one go. If the WMM model has been selected, the file size will be circa 4.1 MB. If the IGRF model has been selected, it will be about 3.6 MB. (Note that the IGRF file includes the same amount of PSX relevant data as the WMM file.)
When the file is downloaded and if you use multiple networked PSX instances, copy the downloaded file to the Terrain subfolders of your other Aerowinx folders as well. It's important that every networked PSX instance loads the same magnetic field data.
How do I load the new file in PSX?
Just restart PSX. PSX loads the file during simulator start (when the start progress is between 79% and 80%).
Where can I check whether PSX has loaded the file?
Go to Instructor > About and find the line starting with "Earth's magnetic field":
(http://aerowinx.com/assets/pics/magvar03.jpg)
The line "Earth's magnetic field" is followed by a database identifier. For example:
IGRF2019 FEB 2019 - Identifies that PSX is using its internal magnetic database from 2019.
IGRF2020 MAR 2021 - Identifies a loaded file based on the IGRF model of 2020, valid for March 2021.
WMM-2020 MAR 2021 - Identifies a loaded file based on the WMM model of 2020, valid for March 2021.
Can I check whether the file contains plausible data?
Go to Instructor > Situation > Position,
select the "World" section, activate the Terrain display, and select the "Mag" checkbox:
(http://aerowinx.com/assets/pics/magvar04.jpg)
What you see now should approximately look like this (internal database from 2019):
(http://aerowinx.com/assets/pics/magvar05.jpg)
Or like this (loaded file from 2021):
(http://aerowinx.com/assets/pics/magvar06.jpg)
Now this is just to demonstrate that the differences are very small. These tiny differences are not related to the plausibility check. To see that the file contains a plausible dataset, just check that the displayed texture doesn't contain any straight, long edges; that would be a sign of an incorrectly formatted database file. Those tiny pixelated corners are normal.
(The global magnetic field model is quantized in 64800 small tiles. Each tile is one latitudinal and longitudinal degree in size, so there are 360 x 180 tiles. The simulator interpolates the values between the tiles internally. The map doesn't show the interpolation.)
How often should I generate a new file?
Once a year. Or once every two years.
Amazing work. File generated and loaded OK.
Thank you Hardy :)
AlexB
Hi Hardy,
Thank you for this great feature.
Hardy,
Many thanks for this wonderful new feature.
Servus Hardy,
Thank you.
Hardy-
As much as it pains me to utter these words, there may well come a day when the last 744 lands permanently, after which, PSX may well be the sole way to experience 747-400 flight. On that day, Joe Sutter will christen you "The Last of the Incredibles".
BZ
C
PS- Is there a "preferred date" for updates (Jan 1, June 1 etc.)? BTW, my update also went smoothly, ta!
Again Hardy thank you so much for your tireless work.
1. Speech-less !!!
2. Fun, you know us ....:
"""Then click the blue Calculate button below the yellow panel (not on this screenshot but on the actual NOAA website)."""
3. Thanks.
H.
Quote from: cavaricooper on Mon, 15 Feb 2021 13:52
PS- Is there a "preferred date" for updates (Jan 1, June 1 etc.)?
December 24
Amazing work, thanks a lot.
Just to have some fun in areas where a change of variation matters most (and where the 747-400 still sits in magnetic heading mode), here is a comparison of the magnetic heading for 1997 (PS1 release data) and 2021 (today).
(http://www.vitzethum.de/forum/psx/BGTL-1997.jpg)(http://www.vitzethum.de/forum/psx/BGTL-2021.jpg)
(Edit: the images don't show up ... did I miss something?)
... 22 degrees of change in variation.
Markus
Quote from: Markus Vitzethum on Tue, 16 Feb 2021 13:54
(Edit: the images don't show up ... did I miss something?)
I can see the images.
Interesting, I see the images in Safari, but they are not present in Chrome.
Magnetic field data successfully installed though, thanks for the enhancement!
I'm waiting for a creative-type to edit the CSV file to make an anomaly in the Bermuda triangle...
I see them in Firefox.
They are not https.
Just an FYI the latest available service bulletin for the 747-400/-8 is just a 2015 MagVar table. Boeing has also published lists of airports where the current Mag variation exceeds the limit as a function of the age of the MagVar table in the ADIRU and that Autolands or NDB approaches are now prohibited.
Thank You.
Quote from: DougSnow on Thu, 18 Feb 2021 21:59
Just an FYI the latest available service bulletin for the 747-400/-8 is just a 2015 MagVar table. Boeing has also published lists of airports where the current Mag variation exceeds the limit as a function of the age of the MagVar table in the ADIRU and that Autolands or NDB approaches are now prohibited.
Interesting the real thing isn't updated!
I presume no operator has newer than 2015 data??
@Hardy: thank you for this feature!
I think an updated table will be available in the 2024-2025 time frame if I am not mistaken. By then the current 2015 data will be out of tolerance for those airports in very Northern latitudes, if NDB or Autolands are required.
Just updated for 2022, thanks again for this!
Thanks for the reminder Will- ditto!
C
Quote from: cavaricooper on Sun, 16 Oct 2022 22:00Thanks for the reminder Will- ditto!
C
Carl,
Glad to see you are back. I was afraid you were going to get blown away. :)
Bode
Just looked on MBF, Boeing is targeting Fall 2023 for the Service Bulletins to be available for operators to update their MagVar tables for the 744 and 747-8...
Such a table is either hard part of the FMC software (inseperable) or else has the same certification requirements ("Parameter Data Item"). This means that it has the same impact as a program code change. And after Boeing's recent goofs with certification, the FAA has clamped down (also on itself) to all players in industry to get this right. So changing the very base of what determines the aircraft's heading knowledge is sort of heavy impact.
Hoppie
Not involved at all in any of this
I was reading the FTD, this is a remove and replace item, a new FMS is getting installed with the new datatable. The Service Bulletins are not yet available with all the painful details, and since we no longer operate/own any 747s (I guess we owned the TNT 47s on paper), I wont be able to see the service docs once they are available.
Quote from: Bluestar on Sun, 16 Oct 2022 22:49Carl,
Glad to see you are back. I was afraid you were going to get blown away. :)
Bode
Thanks Bode! We were VERY lucky... unfortunately South of us, not so much.
C
I think the FMC gets its mag var data from its monthly loaded nav database, and that just for the locations of the loaded database VORs etc. -- if at all.
Each IRU has a fixed mag var table which provides the MAG HDG data when the IRU is in NAV mode, i.e. when the IRU knows the aircraft's present position so that the IRU can look up the variation from the table. This MAG HDG data from the IRU also goes into the FMS and from there to the ND. When the IRU is in ATT mode, the IRU doesn't know the present position and thus can only provide its pure platform heading to the FMS and ND (the platform heading drifts and therefore requires mag heading entries in the FMC from the crew every few minutes) even when the FMS itself operates normally.
|-|ardy
Quote from: DougSnow on Mon, 17 Oct 2022 01:34Just looked on MBF, Boeing is targeting Fall 2023 for the Service Bulletins to be available for operators to update their MagVar tables for the 744 and 747-8...
Has Boeing updated the MagVar tables?
If so, which data does Boeing use?