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News: Precision Simulator update 10.92 (26 October 2019) is now available

Author Topic: Is there a delay between loading winds and seeing the "W"?  (Read 634 times)

Will

  • Join date: May 2009
  • Location: Chicago
  • Posts: 1772
I go to the FMC LEGS page, hit RTE DATA>, and then SEND> to get the latest winds. I go through the usual progression from SENDING, SENT, UPLINK READY, and LOAD>, and then if I click on a waypoint, I see the loaded winds. This took something like 10 seconds. But going back to the RTE DATA> page, the "W" that should be there when winds are loaded is absent for a while. On the ground, it took a few minutes for the W to appear, even though I could hit LSK 3R (for example) and view loaded winds. In flight, for whatever reason, the delay was less, maybe 20 seconds. Is that normal?

Summary: the uploaded winds are viewable in the FMC before the W> symbol appears before a waypoint. Normal behavior?






Will /Chicago /USA

Hardy Heinlin

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Re: Is there a delay between loading winds and seeing the "W"?
« Reply #1 on: Sat, 30 Nov 2019 20:38 »
Maybe the graphic screen refresh for the "W" came a nanosecond before the data sync, and was only updated after the next regular autorefresh which is usually triggered by the next fuel quantity difference check at the latest which  occurs less often on the ground as the engines are not running.

I've never seen this effect. Can you reproduce it?


Cheers,

|-|ardy

Will

  • Join date: May 2009
  • Location: Chicago
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Re: Is there a delay between loading winds and seeing the "W"?
« Reply #2 on: Sat, 30 Nov 2019 20:55 »
Yes, I can reproduce it. Here is a situ that contains the observation I'm reporting. If you load it (W.situ), it's just after I loaded winds. You can see by clicking on any of the waypoints that winds are actually uploaded and present, but instead of showing "W>" next to the LSK, the FMS just shows the carat. Is this how it's supposed to be?

https://www.dropbox.com/s/hi4eint0etvs4xr/W.situ?dl=0
Will /Chicago /USA

asboyd

  • Join date: Jan 2012
  • Location: YSSY
  • Posts: 408
Re: Is there a delay between loading winds and seeing the "W"?
« Reply #3 on: Sat, 30 Nov 2019 21:09 »
I also have noticed this. It used to take a few seconds for W to appear at each line, now it can take up to 60-70 seconds before the W shows up and Exec lights... That is every time after I load my FP (from database) and am told data is available.

Alex B

Hardy Heinlin

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Re: Is there a delay between loading winds and seeing the "W"?
« Reply #4 on: Sat, 30 Nov 2019 21:58 »
I also have noticed this. It used to take a few seconds for W to appear at each line ...

This, however, is normal in PSX and in the real FMC. It loads from leg to leg and this takes several seconds.

Thanks for the situ, Will.

asboyd

  • Join date: Jan 2012
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Re: Is there a delay between loading winds and seeing the "W"?
« Reply #5 on: Sat, 30 Nov 2019 22:06 »
No problems.
Thank you for the reply...

Cheers,
Alex B

Hardy Heinlin

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Re: Is there a delay between loading winds and seeing the "W"?
« Reply #6 on: Mon, 2 Dec 2019 05:41 »
Here is a situ that contains the observation I'm reporting. [...]

https://www.dropbox.com/s/hi4eint0etvs4xr/W.situ?dl=0

Hi Will, this file isn't a situ file. It's just about 700 bytes in size. It may be a bookmark link file.


|-|ardy

Hardy Heinlin

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Re: Is there a delay between loading winds and seeing the "W"?
« Reply #7 on: Wed, 4 Dec 2019 04:30 »
I'm not sure if I have understood the question. I will tell what's intentional:

• Certain short legs won't get the "W". (ACARS data uplinks cost some dollars.)

• The "W" prompts appear one after the other, and this may take some seconds in PSX. In real life it may take a minute. In PSX too it may take a minute when the checkbox "Set zones by flight track ..." is selected. PSX will scan the entire world-wide METARs to compose more plausible enroute data. This takes a while. PSX will do this during the loading simulation, not during the "SendSent" delay simulation; in real life the loading may take a minute, and instead of simulating this delay artificially, PSX does the actual data work during the loading simulation. It's more efficient, and the user won't notice whether the delay is simulated or actual work. Delay is delay. I implemented this METAR related improvement this year, I think.

In short words: Assure that the missing W is really supposed to appear (and not intentionally blank), and expect a long loading time for long routes in real-world METAR scenarios.


Regards,

|-|ardy

Jeroen Hoppenbrouwers

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Re: Is there a delay between loading winds and seeing the "W"?
« Reply #8 on: Wed, 4 Dec 2019 08:43 »
ACARS data uplinks cost some dollars.

Many dollars. We're talking $600 per megabyte.

Will

  • Join date: May 2009
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Re: Is there a delay between loading winds and seeing the "W"?
« Reply #9 on: Wed, 4 Dec 2019 20:45 »
Are there instances when I would see the carat without the W, but could click into the leg and see winds present?

Or is the "W" not displayed until the winds are present for that leg?


Will /Chicago /USA

Hardy Heinlin

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Re: Is there a delay between loading winds and seeing the "W"?
« Reply #10 on: Wed, 4 Dec 2019 20:50 »
There's small font text and big font text. The uplinked data is in big font, the non-uplinked propagated data in between is in small font. What size do you see?

Carets > are always available.
But only some of them have a W.
Only legs containing big font data have a W.

Will

  • Join date: May 2009
  • Location: Chicago
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Re: Is there a delay between loading winds and seeing the "W"?
« Reply #11 on: Wed, 4 Dec 2019 22:49 »
Quote
Carets > are always available.
But only some of them have a W.
Only legs containing big font data have a W.

That's very helpful. I started this topic because I am seeing data in legs without a W. I will check to see if the data are big font or small font.
Will /Chicago /USA

emerydc8

  • Join date: Jun 2015
  • Location: Tucson, AZ USA
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Re: Is there a delay between loading winds and seeing the "W"?
« Reply #12 on: Wed, 4 Dec 2019 23:01 »
ACARS data uplinks cost some dollars.

Many dollars. We're talking $600 per megabyte.

Any idea how many MB a typical wind uplink for an oceanic flight would be? We have guys who religiously uplink new winds every hour and they think they're saving money for the company if they find a better altitude. My suspicion is they're wasting more money by checking winds every hour than they would ever hope to save by an occasional altitude change based on new winds.

Jon

Jeroen Hoppenbrouwers

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Re: Is there a delay between loading winds and seeing the "W"?
« Reply #13 on: Wed, 4 Dec 2019 23:04 »
I'll see if I can catch a wind upload in the wild.

Some operators have a blanket fee for ACARS per aircraft; it all depends on how heavy the stone is that you drop on ARINC's (SITA's) negotiation table.    :-)


Hoppie

Hardy Heinlin

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Re: Is there a delay between loading winds and seeing the "W"?
« Reply #14 on: Wed, 4 Dec 2019 23:52 »
A captain of a major airline in Europe says that 125 characters are circa 0.10 Euro, i.e. wind data for 4 altitudes is 1.40 Euro when uplinked on the ground via VHF, or 1.50 Euro in flight via VHF or SAT .

The actual limit is a technical limit:

1256 characters is the limit for one uplink, of which circa 50 are used for the administration. If you take 20 characters for one waypoint, you have free memory for circa 60 waypoints (60 "W" prompts).

This is valid for the legacy FMC (max 120 legs) and for the NG FMC (max 250 legs).


Regards,

|-|ardy

Britjet

  • Join date: Aug 2014
  • Location: Camberley, UK
  • Posts: 1383
Re: Is there a delay between loading winds and seeing the "W"?
« Reply #15 on: Thu, 5 Dec 2019 09:38 »
In BA we were told initially to restrict ACARS use to VHF coverage if at all possible due to the extra cost of satellite usage.
After that I believe they got a blanket deal so it didn’t matter any more (this was some time ago).
I always thought that multiple wind uplinks were a waste of time personally. They always needed editing to make sense - some of the forecast levels sent were irrelevant - we would already be high above them.
I always found that the initial uplink was accurate to a ton or two, so why fret?
In any case the “optimum” level probably wouldn’t be available anyway on airways routes:-(
In terms of Cost Index - I always had my doubts about that as well, the 747 Wing is an “86” wing. The optimum level graphs show that clearly. Why bumble about at .83 at some weird “optimum” level.
But then I know I’m a bit of a dinosaur in these matters....
Peter

emerydc8

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Re: Is there a delay between loading winds and seeing the "W"?
« Reply #16 on: Fri, 6 Dec 2019 18:54 »
I'll have to see if we have a fee per every use or an all-you-can eat plan. I agree on the M.86, I remember on the Classics that had no autothrottles it was a lot easier to cruise at .85-.86 because the airplane tended to gravitate to that anyway. 

Will

  • Join date: May 2009
  • Location: Chicago
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Re: Is there a delay between loading winds and seeing the "W"?
« Reply #17 on: Sat, 7 Dec 2019 17:31 »
Hello Hardy, I was able to download W.situ from this link:

https://www.dropbox.com/s/u6ubuqhg8bm2nb1/W.situ?dl=0

When I load it, I can see wind data in legs with no "W" in both large and small font.

Clicking into the carat next to DLL shows wind data in large font.

Clicking into the carat next to YVW shows wind data in small font.

Neither DLL nor YVW has a "W" next to the carat.

This is the behavior that I am talking about. Is it normal?
Will /Chicago /USA

Hardy Heinlin

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Re: Is there a delay between loading winds and seeing the "W"?
« Reply #18 on: Sun, 8 Dec 2019 09:29 »
Hi Will,

in your situ the FMC hasn't calculated the ETA, fuel, altitude and speed data yet. This is because your PERF INIT isn't complete (no CRZ ALT, GW, CI).

I guess there should be a "W" for the big font stuff anyway. In PSX the W is blank because the whole ETA/fuel text block on the RTA DATA page is blank. In real life you would first complete your PERF INIT before requesting wind/OAT data. So I don't know whether the real FMC would show the "W". I guess it would. I'll change it in the next update.

The small font wind/OAT data at YVW is just propagated data based on the big font wind/OAT data. This data is independent of FMC predictions.


Regards,

|-|ardy
« Last edit: Sun, 8 Dec 2019 12:35 by Hardy Heinlin »

Will

  • Join date: May 2009
  • Location: Chicago
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Re: Is there a delay between loading winds and seeing the "W"?
« Reply #19 on: Sun, 8 Dec 2019 15:27 »
W.situ was the result of a rushed preflight, which I did just to quickly create a situ that illustrates the absence of the W.

I thought the W was missing on more thorough pre-flights as well (e.g. with PERF INIT complete), but I could be wrong. I can't say for sure where in the preflight workflow I noticed this effect. I will let you know if I see large font entries without the W at other times.

Thanks for looking into it.
Will /Chicago /USA