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Post by Deleted on May 23, 2017 5:53:54 GMT
Hi All,
First of all, this is my first experience of this forum so please excuse me if I have posted in the wrong place, or if this subject has already been done to death.
I have been using FSX for as long as it has existed, but recently, since getting my PPL, I have attempted to use it (with Plan G) for practising my real flights and real planning. I just discovered the 8 degree discrepancy in the MAGVAR Value at my location in Melbourne, Australia.
I have downloaded the BGL that was supposed to fis this, but it has only partly done so. I now have -17 degrees instead of the correct -12 degrees for my location.
So, does anyone know how to further adjust the BGL file to fix this properly, or know of another way?
I would like to enjoy doing my real world flights in FSX to confirm my planning and to fly when the weather is terrible to keep my hand in, but this only works when the winds are zero, as I use an EFB product for flight planning and it downloads real world winds for the time of the flight.
Meanwhile I will try to fly with winds set to 5 degrees less than advised so that I actually arrive where I intended to.
Thanks
VHDUX
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Post by Herve Sors on May 23, 2017 6:49:59 GMT
Hello VHDUX, I'll try to investigate that more in depth but for that I will need more details May I first suggest you read this post aerosors.freeforums.net/thread/112/magnetic-variation-problems-airac-dataThen, could you provide me the exact location at which you performed your test and tell me how you determine the current (wrong) magnetic variation. You may post here or, if you prefer, initiate a private exchange using my email : hsors(at)hotmail(dot)com Regards Hervé |
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Post by Deleted on May 23, 2017 9:04:13 GMT
Hi Herve,
I will try to explain the situation. I am doing flights between Moorabbin YMMB and Latrobe Valley YLTV in Victoria Australia. Both places are quite close to the 12 degrees East MAGVAR line. When I attempted to rehearse this flight in FSX, I found that the wind direction I set in "Weather" was modified by 18 degrees, so then I read the article you referred to and understood that FSX is using very old data, so I downloaded the BGL and now I have a difference of 17 degrees East.
The effect of this is that the wind is not the same as the wind in my plan and my tracks don't work unless the wind is set to zero knots.
I am very interested in your opinion of this.
VHDUX
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Post by Herve Sors on May 23, 2017 12:13:07 GMT
Hi VHDUX
Indeed YMMB and YLTV have now (2017) a 12 degrees East magnetic variation. You may test that by lining up on a runway for which you know true and mag headings
As an example YMMB rwy 13L true heading is 142.1° and should be 130° magnetic (as published). If it is the case, everything is fine with magvar settings
I must say I do not fully understand the information you provided such as "I found that the wind direction I set in "Weather" was modified by 18 degrees" (what is modified?) or "The effect of this is that the wind is not the same as the wind in my plan and my tracks don't work" (what means don't work?)
MagVar has nothing to do with current wind that will only change the relationship between ground track and aircraft heading (according to crosswind component) both for magnetic or true references.
I don't know at all which wind directions are set in the FS weather engine so there could be a problem here
Unfortunately, as far as it has nothing to do with the magnetic variation data, I'm unsure I can help more here
Regards
Hervé
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Post by Herve on May 24, 2017 0:22:09 GMT
You have made me realise that I guessed that FSX uses MAGVAR to display the wind. Let me explain: I go into advanced weather and set a wind to 20 knots at 240 degrees for surface to 5000 feet, for example. On the way out of the weather windows it will display a wind of 223 at 20 knots. When I fly at 2000 feet, it will display a wind of 223 at 10 knots and when I connect to Plan G, it too will display 223 at 10 knots. What else could make this change?
Regards
VHDUX
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Post by Herve Sors on May 24, 2017 7:56:03 GMT
I've absolutely no idea regarding why there is a difference between what you entered on the advanced weather screen and what you read while flying. However, I think wind direction is magnetic here. There have been a lot of posts indicating FSX advanced weather parameters are erratic. Anyway, it has probably nothing to do with magnetic variation settings. The only definitive test you can do to ensure magvar is ok is what I suggested above (lining up on a runway for which you precisely know true heading and checking indicated magnetic heading)
If I have time, I will redo the test with the information you provided and let you know
Regards
Hervé
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Post by Herve on May 28, 2017 1:28:36 GMT
Thanks again. I checked the runway and it is exactly right as you predicted. It appears that weather is done differently and strangely. I also tried using Active Sky Next to set a precise wind and that didn't work either.
I think that I will just have to ignore the simulator winds and test my flights without winds.
VHDUX
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