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teopereira

Forecast winds: where to get and how to insert them in the FMC?

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My questions are:

 

1) How to choose which altitudes to put in the "forecast winds" of the descend page?

 

2) Where do I obtain these forecast winds for those altitudes? Should I use the winds above the arrival location? I use Active Sky Next, but it tells me nothing of these data for my route...

 

3) How can I put the forecast winds for each of my legs in the FMC?

 

4) What's the use of the "Average winds" given by Active Sky Next?

 

Thanks!

 

 

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1) How to choose which altitudes to put in the "forecast winds" of the descend page?
Active sky will tell you the best altitudes, but you still have to fly a correct flight level from  ATC.

3) How can I put the forecast winds for each of my legs in the FMC?
There are no one way of doing this. But if you can save a simple FSX flight plan  and load this into Active Sky.

You can get a weather briefing in the 'briefing Section' in this program and find the average winds. It would be something like 300/045, and it will also list the different winds at the best altitude. In the DES section of the CDU there is a place to put the average wind at a particular altitude.
It seems that you can choose your own increments, but from the videos and tutorials I have seen. it is the top of descent downwards. For example 35000, 330/45,  15000  320/23  3000  300/10
You put in the altimeter setting at the arrival and the ISA/DEV , here as well. The reason for the altimeter setting is If there is a massive difference in pressure, there will be a big jump or discrepancy in altitude within the descend when you change to the local presusure, below the transition altitude. For example you left an airport 1001HPA and arrived at a place 1030HPA. Or the other way round, where you go from high to low pressure.

4) What's the use of the "Average winds" given by Active Sky Next?
The main reason is fuel burn. If you have a head wind it will take more fuel to burn.

 

All this stuff is useful for long flights, and also in cold weather were it is difficult to descend with the anti-ice on, as it uses engine resources.  There is a higher idle with the anti ice on. The DES section helps planning descent. I have seen people ingnore all this, and they still manage to land very well.
It is just prudent checking. And it helps you descend, if you have to be at that FL by a certain time.

 

The descent forecast page will help compute a less/more steep descent based on the inputs you put in. If you look at the map when changing the options, you might see the T/D symbol shift around, as the plan changes.

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There is a wind aloft section in AS fligth plan tab. You can get winds data for ten different FLs from surface to 490. Choose altitudes which cover your descend path best. So that every point of major wind change, you'll have data entered. Don't enter too close to your cruise FL as FMC uses it automatically.

 

3. Actually you can enter winds on FMC RTE DATA page. But if there are too much waypoints it's better to enter average wind to PERF INIT. This will allow more accurate calculations. Be sure to deselect "show surface winds" for more accurate data. Maybe in SP2 we'll have winds data export as on 777X.

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4) What's the use of the "Average winds" given by Active Sky Next?

The main reason is fuel burn. If you have a head wind it will take more fuel to burn.

 

I always thought use the average on short flights and for longer flights enter the winds manually in the legs RTE DATA page? Because on a longer flight its guaranteed winds will change more and won't be the same as the average?

 

Can you use PFPX for the flight levels when entering winds in the DES page? When you print the flight plan off or save it you get winds for climb cruise and des

choose which altitudes to put in the "forecast winds" of the descend page

 

Like i said i always get this from PFPX winds page and look at the des section and it has FL like FL240 244/86 FL180 235/82 etc but i always check this against ASN to see how much its off and its usually on the money maybe -/+ 5

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I always thought use the average on short flights and for longer flights enter the winds manually in the legs RTE DATA page? Because on a longer flight its guaranteed winds will change more and won't be the same as the average?

 

I have no idea about that.

 

I have been using both manual and average on short flights. By short flights I mean 400NM. I have been experimenting with the DES FORECAST page because it is a new thing I am learning on the PMDG, I don't know how accurate is. Like any weather pretiction it's not 100% fall proof. It is a tool which might help a pilot gain a small advantage, in saving fuel and time. Or even a big advantage!

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What i do is enter the average wind in the CRZ WIND column and enter the actual winds for each waypoint in the legs page.

 

Yeh for the DES page i enter the FL from PFPX and keep an eye on them while descending and update them if need be.

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What i do is enter the average wind in the CRZ WIND column and enter the actual winds for each waypoint in the legs page.

 

Yeh for the DES page i enter the FL from PFPX and keep an eye on them while descending and update them if need be.

 

When you say the legs page do you mean the DES FORECAST PAGE?

 

There is a weather brief in PFPX, but I tend to use ASN brief. Maybe I should ingnore ASN and just trust the PFPX brief. Bit more like a flight dispatch office then.

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The main purpose for CRZ WIND entry that i have found is, it optimises ECON CLB calculations and adjust the climb speed.

When you say the legs page do you mean the DES FORECAST PAGE

 

I'm actually referring to question 3

 

 

There is a weather brief in PFPX, but I tend to use ASN brief. Maybe I should ingnore ASN and just trust the PFPX brief. Bit more like a flight dispatch office then.

 

Yeh try it out but always check it against ASN during flight planning phase! Suppose thats what the real pilots do is use there plog

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I'm actually referring to question 3

 

 

 

Ah I'm thinking of the wrong thing, my apologies. No I haven't used weather on individual legs.

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No need to apologies dude!

 

Did you see the des winds for PFPX? Not sure the reason why PFPX chooses those FLs they all seem to be the same on each flight i create.

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No need to apologies dude!

 

Did you see the des winds for PFPX? Not sure the reason why PFPX chooses those FLs they all seem to be the same on each flight i create.

 

Yes I have seen this.

 

But I am having trouble flying more than half way into my route with out my sim crashing. Which is why I'm posting a lot on the CTD forum :(

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Ok i'll try help you over there! I had every crash when i first got my build now i'm in a better place lol

 

But if it keeps crashing something is wrong maybe hardware, an addon etc.

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My questions are:

PMDG 737 NGX Tutorial 2 pages 131-143 covers this subject in detail. Read it and do what it says. Since it was written AS2012 has been replaced by ASN and PFPX is available.

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