Winds & Loading them

[CarlBB]

Hi All,

Appreciate a few threads on this already, however, just looking for confirmation on the following:-

Yesterday I loaded PSX and let it update the weather file. I then un ticked download metars  (as I was going out so the intention was to fly later in the day, but have the wx as it was for the morning departure).

Set zones by track is also selected.

Whilst preparing, I then did a winds request. It said I'd then have around 13.8 tons on landing which I accepted.

Q1 - assuming if I ask the FMC to fetch the winds all day long, in the situation above it would not change?

Q2 - it is therefore reading the actual weather from the waypoints in PSX?

Q3 - if I them randomize jetstreams for september and then fetch winds, I will more than likely get a different predication because I have now asked PSX to give me a different weather scenario? even though PSX is still using my static weather file as a base?

Thanks

Carl

[Jeroen Hoppenbrouwers]

Careful -- the FMC is not capable of reading atmospheric conditions!  It can only read the winds that you have put into your FMC route, which may thus be completely different. You can do this either manually or by downloading via ACARS.  In the latter case, you will get a reasonable forecast, but in no circumstance a direct as-it-really-is download from the atmosphere, simply because this isn't possible in the real world.

The METAR downloads only set the weather at and near the ground. Aloft stuff is never done via METAR, only via the PSX atmosphere settings. It cannot be downloaded from the internet at this moment.

Between ground METAR weather and aloft PSX situations, you get a physically correct, smooth interpolation.

If you want to put in ok aloft weather, snake the jet stream to more or less match the current aloft wind field map. Remember that winds aloft are always a good estimate, but never spot-on accurate anyway.


Hoppie

[Hardy Heinlin]

Yesterday I loaded PSX and let it update the weather file. I then un ticked download metars  (as I was going out so the intention was to fly later in the day, but have the wx as it was for the morning departure).

Set zones by track is also selected.

Whilst preparing, I then did a winds request. It said I'd then have around 13.8 tons on landing which I accepted.

Q1 - assuming if I ask the FMC to fetch the winds all day long, in the situation above it would not change?

It would not change.

Q2 - it is therefore reading the actual weather from the waypoints in PSX?

Waypoints in PSX? The word "PSX" is a bit vague here.

PSX's FMC contains waypoints.
PSX's planet contains a global weather.
PSX's weather men use weather balloons all over the planet.

When the PSX pilot downlinks a wind data request by pushing the respective key in PSX's FMC, PSX will do the following:

1. PSX's ACARS ground station forwards the request to PSX's weather men.

2. PSX's weather men will read the downlinked waypoint coordinates, and will read the wind data in PSX's global weather (data sent by balloons); that is, they will read the wind data at the waypoint coordinates on the chart in the weather men's office.

3. PSX's weather men forward the data to PSX's ACARS ground station.

4. PSX's ACARS ground station uplinks the data to the PSX pilot's FMC.

Q3 - if I them randomize jetstreams for september and then fetch winds, I will more than likely get a different predication because I have now asked PSX to give me a different weather scenario? even though PSX is still using my static weather file as a base?

"... even though PSX is still using"? The word "PSX" is a bit vague again.

When the user changes PSX's global weather, e.g. by re-arranging the jetstreams, then PSX's global weather will be changed.

This user action will not automatically change the wind data entered in PSX's FMC. The user needs to request another wind data uplink, or enter the correct wind data manually into the FMC.

PSX contains:

- a global weather model
- a weather office model that reads PSX's weather at a precision of ca. 80%
- a left FMC model
- a right FMC model

All four models are independent of each other. Each model lives its own life.


Cheers,

|-|ardy

[CarlBB]

Thanks to both for the replies and Hardy for the additional insight at to what is going on behind the scenes.

Just one more question - setting set zones by flight track which is what I assume I need to do when flying a route so that weather updating to the zones is automatic, always sets the time of my simulation back to zulu. Therefore if I am stopping a flight part way through and continuing at a later time, or even returning to say practice again the take off / or the landing of the same previously saved flight, I am presented with a different time than where I left off.

Am I overlooking something? i.e. can setting the time to zule be switched off?

Thanks

Carl

[Hardy Heinlin]

so that weather updating to the zones is automatic, always sets the time of my simulation back to zulu

That's intentional and essential. Real-world weather works with real-world time. You can't mix facts and times. Otherwise, it would lead to paradoxons and break the consistency of the system.

You can move the time slider again after activating automatic weather, but you shouldn't do it if you want to create a scenario where all times are plausible (ATIS, METAR, pilot clocks, etc.).


|-|

[CarlBB]

Hi Hardy

Sorry I omitted that in this case I am not downloading metar - i.e. allow metar files downloaded... is un ticked. Not sure if this would/should make a difference?

It is rare anyway that I need to do this, I see and have discovered that I can move the time slider back. I could of course for these practice scenarios have set zones.... un ticked. As I say, this is generally when I want to practice a take off or landing again from previous flights.

Thanks

Carl

[Hardy Heinlin]

Hi Carl,

"Allow metar files downloaded ..." is under Preferences, hence it's not a Situation variable.

Activating "Set flight track by ..." will copy real-world UTC to simulated UTC. But vice versa, deactivating "Set flight track by ..." will not change any time settings.

To store a situation file with the current situational weather, you should deactivate "Set flight track by ..." and then save it. I understand, however, that -- if you want to continue with real weather after saving this situ -- you have to reactivate "Set flight track by ...". Is this a problem? If you haven't changed your times, they will remain at UTC anyway. Did I overlook something?


Cheers,

|-|ardy

[CarlBB]

Hi Hardy

Thanks for your input.

Yes I understand that what you have written.  Just to provide an answer to " if you want to continue with real weather after saving this situ -- you have to reactivate "Set flight track by ...". Is this a problem? If you haven't changed your times, they will remain at UTC anyway. Did I overlook something?"

It's not a problem, no. All I will say is that I sometimes - quite frequently - I go back to the autosave files as they are by default the one's to load first. e.g., just to practice a take off roll! In this case I can't really untick set flight track by... prior to saving as I did not save it  

If there is way to be able to have an option then I really would appreciate it, but if having such feature would not be in-keeping with PSX then I completely understand.

Thanks again - you've been a great help in making me understand what is going on re: weather and I now have more confidence in future flight planning.

Regards

Carl

[Hardy Heinlin]

Hi Carl,

you can edit your situ file with a text editor. To turn off "Set flight track by ..." in a saved situ, find this line:

WxAutoSet=1

... and change it to:

WxAutoSet=0

... and click Save in the text editor.


Regards,

|-|ardy

[Hardy Heinlin]

I just got an idea for a future update:

New feature:
Saving a situ through the EVENT RCD button will save the situ with WxAutoSet=0.

Background: The EVENT RCD button is obviously a snapshot function for postflight analysis, and not for designing training scenarios. Hence it should keep the situational weather and time and not overwrite it by real-world data present at next situ load.

Does this make sense?


|-|

[CarlBB]

Hi Hardy,

Ok, got it - thanks!

Carl

[Avi]

Does this make sense?

Yes it does.

[Will]

I agree, it makes sense.

[CarlBB]

I just got an idea for a future update:

New feature:
Saving a situ through the EVENT RCD button will save the situ with WxAutoSet=0.

Background: The EVENT RCD button is obviously a snapshot function for postflight analysis, and not for designing training scenarios. Hence it should keep the situational weather and time and not overwrite it by real-world data present at next situ load.

Does this make sense?


|-|

Just spending some more time in the sim this evening now makes me think that saving is one half of the story?

To explain - G-CIVC climbed out of London to cruise alt and then I saved it - un ticking set flight track by..... before saving. Simulated zulu was 13:40

Now... when the crew from G-CIVC reconvene tomorrow evening, and load the situation file, Simulated zulu will still be of course 13:40. When they then tick set flight track by..... Simulated zulu will then be set to current zulu, say 18:30.

My ideal would be for Simulated zulu to stay at 13:40.

May be an additional choice for the current set flight track by.....

set flight track by.....

-- set zulu (only available for selection when set flight track by..... is ticked?)

Thanks

Carl

[Hardy Heinlin]

My ideal would be for Simulated zulu to stay at 13:40.

... and continue old historic real-world weather progress from 13:40 on, on a real-world day of the real-world past?

:-) Nope, Sir, that's impossible!

That would require PSX to record all METARs of all times continuously forever, and that even when PSX is shutdown, -- no, even when the computer is shutdown! -- in order to be able to reproduce every real-world weather progress ever recorded in history for every airport for any duration.

Only Google and the NSA can do this! :-)


Regards,

|-|ardy

[CarlBB]

Hi Hardy

I see what you mean - however just to add once I have downloaded the departure weather - so Preferences .... Download metars is ticked - i then un tick Download metars. My idea is  that I have my departure weather constant for when I reload.

As I fly my route, yes it means I am working with what I assume are metars from the time of departure, but that these metars are interpolated with the planet weather.

So yes, in future - through event rcd - I'll be able to save the situation without set tracks by....which I appreciate. I can then look at the zulu time and restore if necessary.

Summary
Thanks again for your help - I'll also go and play more with the zones / planets as now i've looked - well, looks like fun being able to play with all of these options  

Regards

Carl