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Winds Aloft

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

jalexb88

I believe that it will not be possible to download winds aloft with PSX,  my concern is with flight planning with PFPX without a way to know what winds to use. I was wondering with the simulated winds aloft and jetstreams by season, if it will be possible to extract the simulated wind values from PSX and input them into PFPX so that we have a way to get accurate fuel burns on our OFP while using the excellent upper air simulation described in the manual and not an average wind. Hope that all makes sense.

Alex

jb747

I don't believe that is true.  I have used PSX with PFPX and downloaded the winds aloft into the CDU at the various cruise altitudes with no problems.

Cheers,

Jon

jalexb88

Hi, are you sure about that? I remember Hardy mentioning that it was not possible to get real time upper winds from the internet, I tried finding the post but cant. I might be mistaken though.

Alex

jb747

LOL.  Well anything is possible.  However, if you have the download METARS box checked and load your PFPX flight plan, then go to the legs page and download the winds aloft and load it.... it shows up in the CDU.

Videos of the process are not available but it works.  Alt  OAT, Dir/Speed all show correctly.

Now is it accurate and does it match PFPX?  I didn't check it but it's something for you to do once PSX has been released>   ;)

Cheers,

Jon

jalexb88

I found a post: http://aerowinx.com/forum/topic.php?id=1134 According to that, an external add-on is required to get real world winds aloft in both the planet model and the FMS. It also says the in-sim virtual dispatch does not take data from PFPX but from the simulated PSX atmosphere to load into the FMS, then again maybe this has changed.

If this is indeed how the final version works then what I am wondering is if we can get the PSX virtual dispatch to not only load the winds into the FMS but also into PFPX for flight planning.

Alex

Hardy Heinlin

#5
Hi,

as mentioned in those other threads, the METAR download feature in PSX just downloads METARs, as the name suggests. Not winds aloft.

There are currently two ways to synchronize PSX with PFPX data:

- Copy PSX data to PFPX (read the RTE DATA in PSX's FMC and enter it in PFPX)

... or ...

- Copy PFPX data to PSX

The latter requires an add-on that does not exist yet. An add-on could read the current winds and temps -- valid for the present aircraft coords and altitude -- from an external data source. And then inject this data into PSX every minute or so.

This trick would, of course, override PSX's internal jet stream system, and PSX's dispatch simulation wouldn't know the data along the route. Hence, PSX's ACARS simulation would not be able to uplink the correct aloft data into the simulated FMC. This means, the pilot would have to enter the data into the FMC manually*.


I had a solution in mind, but decided to try this later in order not to delay the release of PSX by yet another year ...


Cheers,

|-|ardy


* There is also a way to insert winds/OAT data directly into a company route. This won't require a network but just a file read/write action. I will document the PSX company route file format on request. -- But mind you, the FMC will not control Mother Earth. The FMC is not a weather god. You can enter whatever you like in the FMC, it won't change anything on PSX's planet. Only the Instructor can change the true weather, and the true time, and the true gross weight, and the true fuel quantity etc. The FMC, on the other hand, cannot change the world, it can only calculate.

jb747

Hardy beat me to it...

I just constructed a new flight plan in PFPX, loaded it into PSX and then compared the winds aloft data at several of the waypoints.

As Hardy pointed out they don't track exactly.  However, for this particular example they weren't that far off.  ;)   Temperature, wind direction and speed were all within 20% and to be honest Mother Nature isn't within 20%.

Cheers,

Jon

JP59

What about the fuel trip consumption calculated by PFPX ? If the winds aloft doesn't match, there will be a risk of low fuel issue during the flight... Does PSX comes with a flight planer and fuel calculator ?

Hardy Heinlin

#8
No, PSX is no route planner. The routes must be entered in the FMS manually or by ACARS uplinks (using company route files from Aerowinx or PFPX).

Yes, PSX has two flight management computers which calculate fuel predictions based on wind and OAT data sensed by the ADCs and IRS at the present position, mixed with wind and OAT data entered by the crew or by ACARS.

When you operate the aircraft correctly in the PSX world, the fuel predictions calculated by PSX's FMS will be very accurate. PSX's dispatch simulation takes probes from PSX's simulated global atmosphere (taking jet streams, troposphere profiles, temp lapse rates etc. into account), and PSX's simulated ACARS can uplink PSX's internal dispatch data (wind & OAT) into PSX's simulated FMS -- referring to the FMS route waypoints.

JP59

Quote from: Hardy Heinlin- Copy PSX data to PFPX (read the RTE DATA in PSX's FMC and enter it in PFPX)


Looks like the easier solution at his time. Of course, having a direct data feed from PFPX to PSX would be the heaven. The best flight planer ever combined with the best 744 simulator ever , wow !

jalexb88

Thanks Hardy! Can the sim give us one average wind value per FL to input into PFPX?

Alex

GodAtum

So I can point PFPX to the PSX weather file?

Hardy Heinlin

Are you familiar with the FMC RTE DATA pages?

There are four flight levels on the FMC RTE DATA pages. And each FMC route waypoint has individual OATs and winds for each of the four flight levels.

To view this on the FMC pages before your flight, you need to request a winds forecast uplink before your flight. I think there is a description in the PDF preview, in chapter "FMS".


|-|

jalexb88

#13
I know there is for each waypoint individually but is there a way to get just one average value of the entire flight plan? PFPX seems to only accepts 1 wind per altitude, I cant input them individually so I was wondering of a way to get an average wind from PSX without having to add all the values up from the FMC and divide and so on LOL that would take a while.

Alex

Hardy Heinlin

#14
You could switch off the jetstream system in PSX and use one wind setting for the entire flight. That would also be your average wind :-)

I have never considered to calculate an "average wind" for a route that has an infinite number of wind data records along a route. How do you want to calculate this?

Maybe like this?
Set 0 wind and note the FMC computed ETA at DEST.
Activate the jetstream model and note the FMC computed ETA at DEST.
Then compare the two ETAs and compute a constant pseudo headwind component? Or a constant pseudo crosswind component?

I don't think this math problem is solveable. It's like: Joe is 5 years old, his dog is 2 years old; how fat is his cat?


|-|

jalexb88

Well because I'd like to fly with the jetstream simulation I will put up with the FMC fuel predictions which Im sure are just fine. By the way the fact that the sim simulates upper air according to the current month it would be safe to say then that the online data for real winds aloft should in theory be close to the aerowinx winds, am I correct?

Alex

Hardy Heinlin

Possibly, theoretically.

Jon says 20% :-)

A larger deviation might occur when you fly inside a jetstream core for a longer period of time. But that's rather unlikely when you ride on standard airways.


|-|ardy

Jeroen Hoppenbrouwers

#17
And mind you, there is no such thing as accurate wind forecasts, anyway. You get a reasonable guess at what you will encounter, based on weather balloons and previous aircraft reports and insight of people encoded in atmosphere simulators at the weather institutes. When you hit the air mass, you become an aviator, not a dispatcher.

Contingency fuel, anyone?


Hoppie

jb747

Bingo... As Jeroen stated the winds aloft are a forecast, not  reality.   How often does your local forecast call for rain and it doesn't occur?  I have a question into a 744 captain friend of mine who regularly flies the long hauls how realistic the winds aloft are and how much the congenital fuel then plays into the planning formula.  Still waiting for a response on that one... But then again he may just now wheels up out of Sydney for San Francisco.  

Just read the text before posting this... Contingency not congenital.  Ha, ha.  I hate iPads

Cheers,

Jon

lzaman

I agree with Jeroen, dispatch winds is 1 thing, real winds another.

Though in 7 years of flying commercial airlines it has to be said the wind aloft forecast are usually spot on and far from those 20% off... But my experience up to now is limited to the European scene thus we have a lot of very reliable sources.

Nowadays we even have ACARS wind uplinks throughout the flight to further 'aid' the FMS in predicting an accurate fuel/time/perfo plan. It's great technology actually...