Winds Aloft

[Bluestar]

I dont want to crash into the discussion here but I would like to offer my own opinion on ActiveSky wind data output versus PFPX wind data & how it interacts with PSX.

Steve,

Thanks for joining the discussion. 

I'm obviously getting things confused. but I just don't understand where.  I am looking at winds from one direction on the Nav Display and looking at entirely different winds from the those I loaded into the Corridor from PFPX.

Where is your PFPX getting it's wind data?

I was going to use PSX.Net today, but I could not get the frequencies for Vatsim to change. 

Bode

[G-CIVA]

Where is your PFPX getting it's wind data?

My PFPX uses the native annual weather subscription which it (PFPX) periodically downloads. I use the wind data output from my PFPX flight plan & insert this into the wind data entry in the relevant Weather Page in my PSX Server/Boost instance.  I do this as follows:

1. Once I have created a PFPX flightplan & exported it into the PSX Routes Folder in the correct format.

2 And ONLY AFTER this flightplan is loaded from the PSX database, activated, EXECuted & ONLY once the relevant COST INDEX & FLIGHT LEVEL is entered on the PSX PERF INIT Page ... as would be the minimum for real world operations. Some flight plan outputs also create DES WINDS, I usually manually input these during the preflight sequence if time allows, or after the TOC when time allows.

Once again, just emphasize - my choice (which has always worked for me) is to keep the scenery generation weather engine (just producing 'eye candy' & the PSX upper wind data (from PFPX) entirely separate.

WidePSX is the application I am using that has a tick box in one of its tabs to actively take control of the ATC client VHF frequencies & synchronize them to the VHF frequencies you select on the PSX Radio tuning heads on the centre pedestal.

I hope this helps.

[Bluestar]

Code Select Expand

I hope this helps.

Thanks Steve, every little bit helps.   

Bode

[G-CIVA]

Bode,

I saw you asked if WidePSX can 'override' PSX "downloaded" METAR below 20000ft in another part of the fora.

To the best of my (limited) knowledge this is not possible.

From my personal experience (a lot) of flying my set up as I have illustrated & described .... I have never had any issues or anomalies with the PSX METAR downloads. They appear to me to originate from a very similar source to the data used by PFPX & the popular online flying environments (VATSIM etc).

[Will]

This could be completely gratuitous at this point... I don't mean to be too basic, so forgive me. But...

1. PFPX gets wind forecasts from its current weather servers.
2. These are presented at the end of the operational flight plan (OFP).
3. These are cut & pasted by the user into PSX, to make the wind corridor.

Therefore...

4. The wind corridor always agrees with the OFP, because they have exactly the same data.
5. Wind data is only given for select waypoints.

Therefore...

6. Wind is interpolated for both the OFP and the FMC. Therefore one again...
7. The wind corridor always agrees with the OFP.

If you ever have a situation where you look at the ND and the wind direction and speed vary from what you expect, you should save a situ file for closer examination. The following should always agree:

A. Wind on the ND
B. Wind on the FMC: Find it on PROG > POS REPORT
C. Wind on the OFP
D. The wind corridor

If these four don't agree, then the error is most likely in setting up the wind corridor. Make sure you cut & pasted properly, make sure the wind corridor is active, check the magenta "blobs" on the map (Instructor > Situation > Position), make sure you have magenta blobs, make sure your aircraft is close to or within one of the blobs.

Also:

8. From the surface vertically up to the corridor, PSX uses local real-world surface weather and smoothly changes the winds as the altitude increases, until you reach the corridor. This means:
9. If you spend a very long time in cruise below the corridor, you may have wind predictions that don't match your experience.

Therefore...

10. Also check that your OFP (that you cut & pasted into your corridor) is giving you wind data at the altitudes you need.

Even with PSX-native, real-world weather injection into PSX(*), only the surface stations will get updated. So real-world weather affects METARs and local airport winds, but the corridor will always match your OFP. This is important: what's on your OFP will be in PSX.

*) Add-ons by third parties may inject weather in different ways. PSX itself only imports surface weather.

(I typically fly trips that are over 10 hours long, but I break them into several days. Each day, the OFP still agrees with PSX, because the wind corridor isn't overwritten by anything. It remains fixed until you update it or cancel it.)

In numerous trips lasting 10+ hours each, the time and fuel agreements between the four things above (the ND, the FMC, and OFP, and the corridor) are in such constant agreement that I purposefully change the slider called "Wind and OAT random deviations" to something other than zero, otherwise the winds are too perfect. As we know, the real world doesn't match the forecast by 100%, so it's more fun (for me) to have some randomness mixed in.

But that's just because the agreement is otherwise so perfect.

Example: I just ended a flight from SBSN to FMCH, with PFPX as the flight planning tool, using real-world weather in PSX and a wind corridor. The trip was planned for 11 hours, 29 minutes, and at takeoff the FMC predicted I would land with 64,100 lbs of fuel. The trip actually took 11 hours, 35 minutes, and I landed with 61,100 lbs of fuel. That feels pretty good, considering I had the wind slider set for some random deviations and there was some vectoring at the destination. Planned contingency fuel was 8000 lbs, so even the difference between predicted and final was within the anticipated window--no need to sweat the discrepancy, and no need to dip into extra fuel or FMC reserves.

Final summary: If the winds on the ND seem off, make a situ and post it. Also compare the ND, the FMC, the corridor, and the OFP for that waypoint and you should see agreement.

Best of luck.

[G-CIVA]

What Will so elloquently said ....

[Will]

Oooops, I forgot to say two things.

First, your flight planning software doesn't have to be PFPX. You could use Simbrief or anything else that generates an OFP with a wind forecast table.

And second, the ND winds may not match the corridor if you are using an add-on that injects winds aloft into PSX. The corridor itself remains static (based on your original OFP) until you cancel it or change it, so the corridor will obviously become out of synch with the PSX weather if there is something else injecting external winds aloft into PSX. If this is what is happening, there are two solutions. Either request an updated OFP with an updated wind table from your virtual dispatch office, and use it to update your wind corridor, or else just live with it, as the OFP always contains forecasts anyway, and forecast winds don't always match what you see when you get airborne.

[Bluestar]

Will,

Thanks for the explanation.

Either request an updated OFP with an updated wind table from your virtual dispatch office, and use it to update your wind corridor, or else just live with it, as the OFP always contains forecasts anyway, and forecast winds don't always match what you see when you get airborne.

Can the OFP be run again, say 6 hours into a 10 hours flight, and the winds aloft created by the "new" OFP be pasted into the Corridor?

Bode

[Will]

Can the OFP be run again, say 6 hours into a 10 hours flight, and the winds aloft created by the "new" OFP be pasted into the Corridor?

Hi Bode,

The answer is: certainly. You can run your OFP as many times as you want, say every 6 hours when new forecasts come out. Then you can cut & paste the new OFP wind table into your wind corridor as needed. Thus, you can update the wind corridor as often as you update your OFP.

Another application here is that if you divert to an alternate, and if your original OFP doesn't include winds for the route between your present position and the alternate, then you can run a new OFP to the alternate and update the corridor with those winds as well.

Whether this is "realistic" depends on operational considerations with your company.

Some long-haul companies update the winds during the trip, others fly the whole flight with the wind forecast created at the time of dispatch. After all, even the best forecasts can be off, so the pilots always need to look at actual fuel consumption and update their planning accordingly, no matter what their OFP says, and no matter how current their forecasts are. The whole reason for carrying extra fuel and for having alternate airports is for things like this, when the real world doesn't match your predictions.

But there are actually two issues here: creating a new OFP, and updating PSX with a new corridor based on updated wind data. You can do both, or neither. But if you wanted, you could do just the latter... you could use your flight planning software to generate an updated wind table and copy that into your PSX wind corridor, without going as far as replacing the original OFP that you're using for navigation.

But to your question: yes, you can update the wind corridor in PSX as often as you update your OFP.

[Jeroen Hoppenbrouwers]

It's just "redispatch" basically. Fly up to point (X) using reasonable but not pessimistic data, and at (X) figure out whether you can still make it to the original destination. Most of the time you can, and you save tons of fuel. Sometimes you cannot, and you deviate to a known fuel alternate and swallow the loss.


Hoppie