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Vargveum

FMC is going crazy with ETA numbers

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Hi!Had a new experience with the NGX -800 today (after flying it very frequently since release). The problem is that the FMC can't calculate ETA anymore. The ETA times in the FMC is just running wild, continously scrolling thru numbers on both the CDU and ND. For what it is worth, this started after I installed UTX Europe earlier today. I am no computer expert, but I don't understand why UTX would interfere with the NGX FMC though. But maybe some of you have an idea? Restart of PC does not help. Have had it two out of of two flights now. Everything else is normal. No faults activated.Need help.Thanks

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Hello Daniel,I think I would start with the basics,and remove UT, reboot again and see does the issue remain,At least that way,you can rule out the latest addition being the cause.If you have system restore still enabled (most don't) you could try a restore point to before the software was installed.

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Hello Daniel, I had this problem and sent a Support Ticket but reply back stated they had no knowledge of this occurrence and could not give me a fix. So I started trying various ways to overcome the problem. The following fix works everytime for me but I must emphasise that the Liveries concerned are those from PMDG. Note the tail no. of the livery under cockpit clock. Load up the panel as you would and save it using livery no. plus 737 version in scratchpad i.e. G-ABCD-700. Go to Startup State and do the same. Exit FS . Startup FS again and go to Load Panel State and you should see the data you saved, click LSK at data and activate, repeat for Startup State if data not showing on screen. Sorry for the long spiel but I could not shorten it. Hope it works for you. richard welsh.

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It's definitely not a problem with UTX Europe. I've run the NGX on UTX Europe since it came out, all of my flights are in Europe and I haven't seen the problem you reported.

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Just a little update; the problem seems to be linked to an actual aircraft/tailnumber. Switched livery and voila. Problem gone! Will make another test later. Dave: glad to hear that.Regards

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I've been getting something similar, but only on some routes, some times. Most likely to do with weather if anything. I'm not using UTX.Basically the TOD point jumps around by a few NM constantly a few times per second until passing it where it disappears (ofcourse). During the descent, longer legs can also show the ETA jumping by one minute back and forth multiple times per second.If anything, it's probably just PMDG's code being too 'quick' and accurate. It ought to normalise this over a period of a few seconds or so (IMO). Though I'm not to know that certain situations in the real thing wouldn't produce the same outcome either...

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In this case the TOD didn't jump. the Zulu-time numbers were just spinning, jumping really fast from 2341 to 0513 to 1523 etc. Made another flight just now. No problems. Haven't re-tested the bird that was "bad" yet. But I am now convinced it has nothing to do with UTX.

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It happened to me once and it stopped mid-flight with no more issue. I can't reproduce the issue, even with the same livery, route and time of day.

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Took these screens today to illustrate the issue. Note: the sim is paused when taking these, so there's no changing wind effects etc. This swapping is happening on a few times per second basis.

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In this case the TOD didn't jump. the Zulu-time numbers were just spinning, jumping really fast from 2341 to 0513 to 1523 etc. Made another flight just now. No problems. Haven't re-tested the bird that was "bad" yet. But I am now convinced it has nothing to do with UTX.
I had this happen to me yesterday. I was flying a SWA737-700 KLAS-KLAX. I first noticed this on the progress page. The estimated times for the next waypoints were constantly changing every second or so. I also saw that "spinning" zulu time on the ND. Everything else seemed to be working fine. FYI, I don't have UTX (I dont even know what that is), and I had flown that particular SWA plane before, with no issues. I'll try flying that same plane/route in about an hour and see if this same thing happens.

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I had this happen to me yesterday. I was flying a SWA737-700 KLAS-KLAX. I first noticed this on the progress page. The estimated times for the next waypoints were constantly changing every second or so. I also saw that "spinning" zulu time on the ND. Everything else seemed to be working fine. FYI, I don't have UTX (I dont even know what that is), and I had flown that particular SWA plane before, with no issues. I'll try flying that same plane/route in about an hour and see if this same thing happens.
The glitch occurs every now and again. It's not, like I originally thought, linked to a specific aircraft. Don't know what causes it really. However, it's something that has come up recently. Oh well.... Anyway, this is UTX. http://www.flight1.com/products.asp?product=utxusa

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Nothing to do with UTX, happens over default, Orbx. Not something I have pinned down yet.

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- I have the same problem too, from time to time.

 

But then i realize im flying an extremely complex machine - and its no big deal really.

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How can scenery interfere with the FMC computations? I'd expect more than a slight error in ToD calculation - more like CTDs from bad memory writes!

 

The algorithms are going a bit nuts, that's all (e.g. rounding errors). I can get some very strange numbers if I do things right! e.g. 2147483648 hours to destination, or 546231 lbs of fuel at DEST.

 

Best regards,

Robin.

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I reported this problem sometime back and had no responses that helped. But, I know how to cure the problem when it occurs. In my case this occurs when I'm at the gate programming the FMC, specifically when I insert the cruise altitude. If I insert the OAT temp before pushing the EXEC button (which lights up right after you put in your selected cruise altitude) then the spinning starts. Every once in awhile it happens even if I select EXEC immediatly after inserting the ALT. Then I just change OAT to something radically different than the actual temp and then immeditely switch back and insert the true OAT. And, the spining stops. So, in conclusion i believe it has something to do with some glitch with OAT and programming the FMC.

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Is it possible that for the next SP after the 777 this could be checked, I try to CLR any fault entry on ISA but sometime it doesn't stop to getting crazy.

Thank you

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Is it possible that for the next SP after the 777 this could be checked, I try to CLR any fault entry on ISA but sometime it doesn't stop to getting crazy.

Thank you

 

We still haven't tracked down the precise cause in the code, but I know that once it starts doing it you can't stop it until the sim is restarted. The ISA or T/C OAT entry you make must be in range (usually this means somewhere in the general vicinity of -56C for the temp - the most common way to trigger it is by putting a positive temp in like 56C) or it'll do this. This is something somewhere in the depths of the VNAV path solver - I'm going to make sure we look at it for SP2.

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We still haven't tracked down the precise cause in the code, but I know that once it starts doing it you can't stop it until the sim is restarted. The ISA or T/C OAT entry you make must be in range (usually this means somewhere in the general vicinity of -56C for the temp - the most common way to trigger it is by putting a positive temp in like 56C) or it'll do this. This is something somewhere in the depths of the VNAV path solver - I'm going to make sure we look at it for SP2.

Thank's and good hunting.

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