[FSX Winds Aloft, something is messing with them]

Yes, that is a well known bug in FSX's weather system. Actually the same bug is in FS9 as well, but in that case FSUIPC manages to overcome it. In FSX it isn't always successful, though it does try. The bug is in the way FS tries to interpolate the weather at the aircraft from what should be the three weather stations in its triangular area. What happens is that often one of the triangle vertices is a weather station many hundreds of miles away with completely different weather.

There is another, extra, bug in FSX which makes it worse than FS9. When weather is set via the SimConnect interface (which is the only way known for FSX), the upper wind and temperature layers get into a right mess, getting cduplicated and triplicated, sometimes with layers only a few metres apart. This plays terrible havoc with any wind and temperature progression through the altitudes.

If you are having weather set by ActiveSky or an on-line ATC program, your FSX weather mode is not relevant. As soon as they start setting the weather it changes to "Custom" mode, and they are then in charge, or at least in charge as much as they are allowed with SimConnect which doesn't offer the same degree of control as FSUIPC3 does for previous versions of FS.

I currently use ASA rather than ASX, and it does manage to overcome some of the problems a little better than ASX, but they are still there. The unfortunate thing was that Microsoft knew about these problems before the FS team's demise, but apparently couldn't work out how to fix them after the young lady responsible for the weather system design had left the team. I believe they were in the process of re-writing the weather handling altogether for FSXI.

One way ASA does get around the problem is by what it calls "DWC" (Direct Wind Control). This is actually a mode which sets FSX into Global Weather mode. Global weather mode was a facility added to FSX for flight training purposes. It makes the weather fixed and the same all over the world. This then prevents any problems with interpolation or layer build-up. ASA then modifies that global weather as you fly. The only problem with that is when using programs like Radar Contact to obtain ATIS weather information for destinations -- obviously, if it asks FS, it gets the same weather as at the aircraft. Same goes for ATC and AI assigned runways, though I think ASA has a facility to lock to the destination airport weather far enough out for that to be sorted.

There's really no perfect answer. Over the three years and a bit of FSX's life so far it has become a pretty well known problem and folks just live with it, I guess.

Regards

Pete

Hi Pete,

and thanks for the wonderful explenation, this has been bugging me as well for quite some time, and has elevated my blood pressure surely for good.

It's been some time since your post, so I am not sure if you get this, but I'll try...

I don't know how the wind smoothing option of your FSUIPC works, but with ASE I see that it has to set global weather (as you say above), in order to

smooth the winds. I can say the wind changes are about 1 deg. pr. second, so there are no sudden wind shifts for the aircraft. Though, I don't really

like it when all the weather around me suddenly changes totally for every new reporting station I pass...

Should it not be possible to have a program like ASE (or FSUIPC) recognizing sudden wind shifts, and distribute the change over say 1 minute's time?

The global weather "solution" seems like giving up one thing to get another, and it is impossible to get both..

Winds shifts can occur quite more frequently than one minute, but I guess it would be sort of an "average" (the distribution), which

should be somewhat the correct value..?

I really have now idea, I am no programmer... Just needed to "air" my thoughts :)

How does your FSUIPC do it? And where can I find a page to tell me other benefits of your program? I felt buing it just for the wind

smoothing option was overdoing it maybe.. :)

Actually, right now these days I am corresponding with microsoft about the problem, and they seem to have no idea at all about this

problem...(which I find really wierd). Actually the tried to call me today, but I was at dinner... So maybe I'll hear from them tomorrow..

Will be quite interesting to hear what they have to say... :)

Anyway.. Merry christmas :)

Greetings from Norway

Geir - ATPL student