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Winds Aloft

Started by jalexb88, Wed, 16 Jul 2014 16:08


Hardy, I read this thread and understand why you didn't release PSX with an add-on to synchronize PSX winds aloft with PFPX. I wonder if you actually or you plan to develop it and when it would be available ? It would be fine to have the PSX world synchronized with the real world in terms of weather conditions and winds aloft in order to have the PFPX winds aloft and fuel predictions synchronized with what we'll "see" within PSX.

Hardy Heinlin

It's on my plan.


Great to listen  :D


As I understand from page 41 of preview manual, one may actually change the position and orientation of the two northern and two southern hemisphere jet streams on the map in the instructor station >situation >weather >planet page by dragging the cyan circles embedded in each jetstream.

My plan is to use upper-level prog charts published daily like this one from the US aviation weather web site:

This particular chart shows the jet stream "general" orientation over the central and southern Pacific for today, 24 July. Evidently there is a very sharp change in direction of the southern sub tropical jet over Australia, while farther to the east, the jet flattens out.

Farther south, the southern polar jet makes a more gradual dip towards Antarctica, before coming back north to the east of Australia.

Should be an easy matter to shape the jet streams in the instructor station to match what is shown in the daily prog charts.

Though the prog charts do not give a lot of detail regarding specific wind velocities, temperatures etc, at least the wind direction in PSX would be pretty close over any given location, if using the prog charts as a guide to shape the jet stream pattern. For instance, a flight traveling east or westbound over Australia today (24-25 July) in the FL300 to FL400 range would experience a significant change in upper wind direction (amost a 180 degree shift) over a relatively short horizontal distance.


Hello everyone. Just for fun, I did a flight looking carefully at the comparison between PSX and PFPX winds aloft and resulting fuel burn.

Setup was like this:

+ PFPX using downloaded real-world data to create a flight plan
+ PSX using downloaded METARs and the PSX internal winds aloft model; winds uploaded to FMC


1. The real-world forecasts did a very reasonable job of forecasting the winds in PSX. I'd agree with the 20% number mentioned above, but not always 20% error in the same direction. That means that over the whole flight, the errors tended to cancel each other out to some extent.

2. Legs were of typical length, from 30 miles up to 150 miles or so (with outliers). The error between planned fuel burn and predicted fuel burn, in hundreds of pounds, at each waypoint, went something like this (after correcting for differences between planned and actual fuel at takeoff): +3, +3, +4, +4, +2, -1, -1, -1, -2, -3, -3, -2, -2, -1, +1, +1, -2, -3, -2, -5, -4, -5, -2, -1, -2, etc. So there was almost always a difference between predicted and actual, and the fuel variance rotated slowly between an excess and a deficit. But on the whole, the errors tended to cancel each other out and the aircraft landed reasonably on schedule, without using reserve fuel.

3. The total variance and the pattern of variance will certainly be different on different days, routes, and flights.

NOTE: While it might seem like a good idea to inject PFPX "real world" winds into PSX, in fact, that isn't how the real world works. Aircraft take off into a forecast atmosphere, not a guaranteed atmosphere. (Recall that METARs are observations, whereas winds aloft are forecasts.) You'd fly with more realism if you use the day's real-world actual forecast for flight planning, and then use PSX's internal model for seasonally adjusted, simulated winds. Keep in mind that PSX changes the winds up as the seasons go by, so the PSX atmosphere should look, on average, passably like the real one, when averaged across time and space.

And what happens if the real-world winds vary greatly from what you happen to find in PSX? Well, that would be a realistic simulation of actual challenges that actual pilots really face when flying across great distances.

The largest variance would occur when the simulated jetstream is greatly displaced from the actual jetstream. But as JRBarrett suggests above, you can just drag the PSX jetstream into a reasonable facsimile of the real one based on upper level prog charts, and then go fly. And don't obsess about precision. Remember that the real forecasts aren't all that precise. Here's today's for example:
Will /Chicago /USA



one question about this issue.
I load the Basic 009 scenario in PSX. Goto the RTE page  and request SEND. After a few seconds I can load the wind data. Then go into the Wind page to have a look on the fresh loaded winds. At the same time the EXEC lights up. After a few seconds waiting, the RTE page is suddenly empty! All legs are gone! Do I something wrong or is this a bug or a normal behavior of the FMC?

PS: Just tested it with Training 705, the same behavior.

Hardy Heinlin


never seen this before. Did you accidentally switch from RTE 1 to RTE 2?

Please be as specific as possible when you're describing something.

Upload a situ and describe the steps to reproduce the problem.

OK, we all have Training 705 situ. Just describe the steps. Step by step.




You mixing RTE page LSK4 (send) with LEGS DATA page RSK6 perhaps (send)?

Loaded route instead of winds?


Ok. I open the Basic 009 scenario, because the ACT RTE 1LEGS page is open already. Then RTE DATA,then request SEND. After a few seconds i push the LOAD button. Then the EXEC key illuminates and you can go to the wind page from , for example, the waypoint RAFEE. Here I can see for a few seconds the fresh downloaded winds. Suddenly all waypoints are gone and in the TOP of the CDU reads MOD WIND 0/0, On the ND the route still exists. When you push the RTE button on the CDU you see, that even Origin and destination airport are gone. When I now push the illuminated EXEC key the route is gone on the ND too.


Will make a restart of PSX and see what happens.


Puh.So now after the restart, it seems everything is ok for now.  :) I can switch to the ACT RAFEE WIND page stay there and no deleting anymore. Perhaps a memory problem.


Hardy Heinlin

I can't reproduce this here. It's all fine. Nothing is deleted, neither before nor after the execution.

You mentioned strange "deleted" things before, with situ files. Is your computer 100% OK?


I hope he is ok. :lol:
But I must admit I have another curious behavior, which I cannot explain at the moment.
I will do some testing tomorrow and will perhaps post it here.
Nevertheless thank you Hardy for the help. Perhaps it is not a bad idea to do a restart of the simulator every day or so.

Good evening

Hardy Heinlin

PSX doesn't need a restart.

By the way, when your modified route is empty, and you EXECute this emptiness, you will get active emptiness, of course. And the active route on the ND will disappear as well. This is normal. When you ERASE this modification, you will return to your active, unmodified route.


Ok, so I don't call it restart, but closing and reopening ;)
But I really have to say, absolutely outstanding job from you. PSX is running solid as a rock. If only all software would be so stable. :roll:
Unfortunately I cannot test it anymore because it it ok now. It would have been interesting to see if after pushing "Erase" really everything returned. I will stay tuned and if I get perhaps this behavior in the future a second time, I will make a video.



I think what Hardy means is that PSX is running solidly, and you don't need to shut it down, close it, restart it, reboot it, relaunch it, or anything else.

With other sims, some people have gotten in the habit of doing these large-scale resets to try and fix faults or clear out unexplained behavior. (Even to the point of rebooting the computer, reinstalling the software, reinstalling Windows, whatever.)

I promise you that PSX isn't like that. It doesn't need any hard resets to clear any internal faults. Just reload the situation, which resets the simulator to a previously-defined state, and proceed as you were before.
Will /Chicago /USA


You are right, Will. And I have absolutely no doubt, that PSX is running very stable.  Since I received my copy I had to close it three times, and this was for the installation of a new Joystick. But today with my special problem it seems that reloading the situation doesn't change anything. And only after closing and opening PSX it is ok. I am really a little bit frustrated that i have not made a video. I have tested it at least twenty times. And now the problem is gone and will perhaps never ever reappeare :? (But I have another phenomenon
in the backhand  :D Let's see what happens tomorrow)


Martin Baker

A question about the relationship between winds aloft and METARs downloaded from the internet:

If in Situation/Weather/Planet the box at the bottom left of the screen "Set zones by flight track and downloaded METARS" is ticked (and shows "Internet is on") do these METARS override the winds aloft as created by manually setting up the jet streams at the top of the page?

My assumption was that they don't, that the real-time downloaded METARS blend into the simulated upper winds created in the planet section, but I see that the METARS are active up to 50,000' so possibly they do override the planet tab's upper winds.

Which is it?

Many thanks, M

Hardy Heinlin

The winds are interpolated vertically from surface winds (zone weather) up to tropopause winds (planet weather).

Same for OATs.

Clouds are set by zone weather only.



Michel Vandaele

Quote from: Hardy HeinlinThe winds are interpolated vertically from surface winds (zone weather) up to tropopause winds (planet weather).

Same for OATs.

Hi Hardy, does this means that as harder the winds are at the surface, as stronger the ALOFT winds will be ?  

This afternoon I did a flight from EGSS/ELLX  Crz FL230 .  Winds according PFPX flight planning were for example over DVR   329/073 - KONAN 329/076 - KOK 329/078  which in on UL607 for info )  when I checked the wind indictor in the ND is was always around 260-285 / +/- 26 kts . This looks a very big difference which is probably created by a present stormfront.  Will check next time if I can adapt the jet stream in the model, to the real position.   B. Rgds
Board member  FSCB
EBOS Scenery Designteam
My B744 project

Hardy Heinlin

Hi Michel,

no, there is a wind direction interpolation and there is a wind speed interpolation.

Surface data remain surface data. Aloft data remain aloft data. Interpolation is a method that fills the missing data between surface and aloft.