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Driver170

Working out average DES winds

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I'm hoping someone can steer me in the right direction on how to work out average DES winds?

 

And also why on TAKEOFF PAGE 1 you have GW and TOW and the TOW doesn't decrease as the fuel is getting burnt during taxi, but the GW does reduce? can someone explain this?

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I'm hoping someone can steer me in the right direction on how to work out average DES winds?

 

 

 

 


And also why on TAKEOFF PAGE 1 you have GW and TOW and the TOW doesn't decrease as the fuel is getting burnt during taxi, but the GW does reduce? can someone explain this?

 

Your GW is your ACTUAL gross weight, which will change as fuel burns off.

 

Your TOW is your PLANNED take off weight, which should not change as fuel burns off. You shouldn't be burning so much fuel that this value changes significantly. If you plan to, ensure that your TOW entry accounts for that change.

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cheers!

 

The TOW was 60.2 t and the GW was 60t when i lined up on the rwy?

Been looking at the CRZ wind entry in the PERF INIT page and found you enter the TOC wind and enter the wind in the legs page!

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The TOW was 60.2 t and the GW was 60t when i lined up on the rwy?

 

This is because the TOW auto-populates when you finish your PERF INIT info, I believe. Of course, you burn fuel in the taxi, so your GW decreases.

 

The FMC doesn't know what your taxi time, or distance will be, so it cannot assume a lower value than the auto value that it's given. Either adjust it to the current value when you get to the runway, or ignore the difference (provided it's negligible, which 200kg would be). Another option would be to use the value assumed in TOPCAT (it will give you an assumed TOW using your planned GW minus the assumed taxi fuel).

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So how do i actually change this TOW?

Kyle in the 737 NGX fs options i set my ZWF in the right to 55.3 t and my GW is then 60.1 do i can match my PFPX weights!

 

So how come in the PERF INIT page it shows GW 60.2 ?

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So how do i actually change this TOW?

Kyle in the 737 NGX fs options i set my ZWF in the right to 55.3 t and my GW is then 60.1 do i can match my PFPX weights!

 

So how come in the PERF INIT page it shows GW 60.2 ?

Honestly, you're hyperfocusing if you're worried about 100kg. You easily make up for that in the fact that passenger weights are averaged anyway, so your weights are already "wrong" even if you calculated it all "perfectly."

 

To answer your question, I believe you can adjust the TOW on the TAKEOFF REF page at the bottom right(-ish - going off of memory here).

 

The difference in weights between the FS ACTIONS page and the actual FMC side is due to rounding errors and the errors inherent in the actual gauges (simulated realistically).

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TOW is the RELEASE weight - what the company says you can takeoff at. The GW is the ZFW+fuel or your actual.

 

As far as regs go, your TOW should be equal to or less than the Release GW. You need to make sure you also have your REQ fuel.

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Driver170, on 06 May 2015 - 8:08 PM, said:

So how do i actually change this TOW?

Kyle in the 737 NGX fs options i set my ZWF in the right to 55.3 t and my GW is then 60.1 do i can match my PFPX weights!

 

So how come in the PERF INIT page it shows GW 60.2 ?

 

Honestly, you're hyperfocusing if you're worried about 100kg. You easily make up for that in the fact that passenger weights are averaged anyway, so your weights are already "wrong" even if you calculated it all "perfectly."

 

To answer your question, I believe you can adjust the TOW on the TAKEOFF REF page at the bottom right(-ish - going off of memory here).

 

The difference in weights between the FS ACTIONS page and the actual FMC side is due to rounding errors and the errors inherent in the actual gauges (simulated realistically).

 

I found a way to get it all matching by setting the weights in the PMDG first (pax and cargo etc) and then populate it in PFPX :)

 

I tried to change my TOW to 60.1 from 60.2 but it wouldn't change in the takeoff page 1

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TOW is the RELEASE weight - what the company says you can takeoff at. The GW is the ZFW+fuel or your actual.

 

As far as regs go, your TOW should be equal to or less than the Release GW. You need to make sure you also have your REQ fuel.

 

Thats the thing matt in the takeoff page 1 my TOW is fixed and stays at 60.2 but my GW reduces by 200kg at around my line up point which is my taxi fuel that has been burnt. But i can't seem to change this TOW fix

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Kyle can i just enter the ZFW in the PERF INIT PAGE like in the RW because this seems to work and match?

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Vernon

 

I get the ZFW in either way. Enter it thru FS ACTIONS>PAYLOAD or just key the ZFW as reported by PFPX on the INIT page. It makes no difference.

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It does make a difference with what way you enter it.

 

If you enter payload through FS OPTIONS your ZFW will be diff to PFPX ZFW

 

If you enter it through PERF INIT its spot on and matches PFPX

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TOW  GW is the RELEASE weight - what the company says you can takeoff at. The GW TOW is the ZFW+fuel or your actual.

 

As far as regs go, your TOW GW should be equal to or less than the Release GW TOW. You need to make sure you also have your REQ fuel.

 

Sorry, I reversed them.

Thats the thing matt in the takeoff page 1 my TOW is fixed and stays at 60.2 but my GW reduces by 200kg at around my line up point which is my taxi fuel that has been burnt. But i can't seem to change this TOW fix

 

Yeah, I screwed that up. It's the other way around. GW is the one that's changing with fuel. TOW is (at least at my company) the "release weight."

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Wouldn't you just say MIN TOW then matt instead of GW

Yeah, I screwed that up. It's the other way around. GW is the one that's changing with fuel. TOW is (at least at my company) the "release weight."

 

So basically TOW is the ramp weight by the sound of it?

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Wouldn't you just say MIN TOW then matt instead of GW

 

So basically TOW is the ramp weight by the sound of it?

RAMP would be TOW+TAXI.

 

Or RAMP-TAXI=TOW.

 

When you line up, make sure you have REQ fuel.

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Yeh TOW is minus taxi! Well it should be. And at takeoff i always make sure i have sufficient fuel to complete the flight.

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It does make a difference with what way you enter it.

What difference does a couple of hundred pounds make?

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Why? Well i asked a pilot that i speak too and he said -

 

There should be no difference between the ZFW from the loadsheet and the FMC as the loadsheed ZFW will be entered into the PERF INIT page. The GW should be close, preferably within a 100kgs and it usually is, only difference could be due to either fueling a bit more than planned or longer than planned APU runtime.

 

 

So when i have my PFPX OFP in front of me i expect my ZFW to match the NGX like it does in real life but like that pilot said the GW should be off 100kg, which it does in my NGX and i'm perfectly happy with that.

 

So what i do is enter my ZFW from PFPX and then set my fuel and it all matches up perfect now except the GW which is understandable because the FMS over reads

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like it does in real life

 

Not really. Your friend fed you poor information (not bad, just poor).

 

Look at a flight release. Note that there's a line next to all of those numbers. Why would there be an ACT line there if it was perfect every time? It's not.

 

Last minute non-rev. Better print out a new release!

Nope. Note the change on the paperwork, ensure it doesn't put you over limits, sign, send, done.

 

Aviation isn't cut and dry, and it's not perfect. Numbers are never "bang on."

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Last minute non-rev. Better print out a new release!

Nope. Note the change on the paperwork, ensure it doesn't put you over limits, sign, send, done.

 

[ed note: Dang it! I have a beautiful bullet point example with math and stuff. I killed it somehow with my new computer. Grrr.]

 

Actually, that is how my company does it. We do get a new release. Our ZFW should always match.

 

Other companies have a figure they can use for overweight or underweight to figure out the new fuel burn to make sure they won't be short on fuel or heavy on landing. Say, every 1000lbs of weight = 0.2lbs of change in fuel burn.

 

We have everything automated and it updates and fixes pretty easily. Good stuff.

 

I'll maybe re-type my example, but it's time to cook some dinner.

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[ed note: Dang it! I have a beautiful bullet point example with math and stuff. I killed it somehow with my new computer. Grrr.]

 

Actually, that is how my company does it. We do get a new release. Our ZFW should always match.

 

Other companies have a figure they can use for overweight or underweight to figure out the new fuel burn to make sure they won't be short on fuel or heavy on landing. Say, every 1000lbs of weight = 0.2lbs of change in fuel burn.

 

We have everything automated and it updates and fixes pretty easily. Good stuff.

 

I'll maybe re-type my example, but it's time to cook some dinner.

Really? Hmm. A bunch of my ramp/airline time was spent with an LCC, and that extra paper was a luxury. I guess it would make sense to print a new release as long as you're printing a new manifest.

 

What about bag count discreps?

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I'm hoping someone can steer me in the right direction on how to work out average DES winds?

 

If you are referring to the descent forecast page there are as many different techniques for entering the information as there are Boeing pilots.  I enter the winds for FL340, FL240 and 14,000 feet.  I put in a rough estimate of the temperature deviation, no need to do the math as it's not going to matter that much.  Altimeter setting is self explanatory.  If I think I will need anti-ice for the descent I'll set the altitudes based on the destination weather.  I'm usually doing this just after reaching the top of climb so it's just an estimate at that point.

 

Some pilots only put in the descent winds if there is a tailwind.  Others never put anything in.  It's all technique.

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Really? Hmm. A bunch of my ramp/airline time was spent with an LCC, and that extra paper was a luxury. I guess it would make sense to print a new release as long as you're printing a new manifest.

 

What about bag count discreps?

We get a Load Closeout before we push via ACARS. This has our pax count and ZFW and a few other things.

 

If we are getting ready to push and we get a MASTER CAUTION - DOORS, the rampers have probably opened the FWD CARGO to add a bag. The LOAD CLOSEOUT revision will probably chime the ACARS in a few seconds. It's all automated and quick. Sometimes we'll get a revision or two without notice saying there was a change in bags. No biggie unless it causes us to go over a release weight and then we'll get an Amendment to our release at about the same time over ACARS.

 

When I was at the regionals, I did thousands of Load Manifests by hand and we did have a column for last minute bags.

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I thought they should be bang on! He said - The loadsheet (in full: load and trim sheet) contains only the weight and balance information and the ZFW should match.

If you are referring to the descent forecast page there are as many different techniques for entering the information as there are Boeing pilots.  I enter the winds for FL340, FL240 and 14,000 feet.  I put in a rough estimate of the temperature deviation, no need to do the math as it's not going to matter that much.  Altimeter setting is self explanatory.  If I think I will need anti-ice for the descent I'll set the altitudes based on the destination weather.  I'm usually doing this just after reaching the top of climb so it's just an estimate at that point.

 

Some pilots only put in the descent winds if there is a tailwind.  Others never put anything in.  It's all technique.

 

Hi joe, Thats not what i'm looking for! I'm looking to find out how to average out the descent winds so i can use it for my descent planning.

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Thats not what i'm looking for! I'm looking to find out how to average out the descent winds so i can use it for my descent planning.

 

Vernon,

 

There's no need to get an average if you're using the method Joe prescribed. Using the function on the DES forecast page will do it all for you.

 

If you're looking to average the wind, some basic maths will be just fine:

Sum all the wind at each altitude. Divide by number of altitudes.

Sum all of the degrees at each altitude. Divide by number of altitudes.

 

No idea why one wouldn't use the method my video, or Joe is referencing, though...

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