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Aerosoft CRJ Developers...Please answer this question on LNAV Tracking issue (over-correcting, swaying back and forth)


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1 hour ago, Secondator said:

I am going to unlock this thread again after a week of closure. Please keep it civil and on topic from now on.

A word from the development side. We have been monitoring this issue and have been able to occasionally recreate it, but it's very random so far. When we have been able to recreate it, we have tried several approaches to mitigate the issue but since it's so hard to recreate (even if you fly exactly same flight, same conditions etc. it might not happen), testing the possible fixes is not easy either. So overall, the issue is known, and we are constantly looking out for it trying to find ways to reliably recreate it.

Therefore I call for public help on this matter. If anyone experiences this issue, please post it here together with screenshots or even better with a video including as much details as possible. Important details especially are the aircraft type (variant), route, location of the issue (which leg it happened), aircraft weight and balance (screenshot from the EFB) and weather conditions (especially the wind). While other discussion of the topic is allowed as long as it's kept civil, this kind of detailed reports should be the priority. They offer the most help to us.

I assure you once again that this issue, or CRJ development in general, has not been forgotten and we want to get it fixed for you as much as you want to see it being fixed. The biggest roadblock is that we are unable to reliably recreate the issue which significantly slows down the investigation.

Great news! Thank you. I am away, but when I return, I will continue with my flights and have OBS running in the background to capture video footage. I don't know if it is related, but after takeoff, the CRJ will often not fly an intercept to the first waypoint. It may fly parallel at quite a distance from the line drawn to the waypoint. For now, my workaround is to fly heading bug until I'm on course and in line with the next waypoint, then go direct inc. Again, not sure if it's related. I will say that many flights in this plane are thoroughly enjoyable and I don't encounter the issue either on every flight. Because the aircraft is great in so many ways, it just detracts from the generally excellent experience. 

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  • 4 weeks later...

I have noticed lately that there is about a 14-16 degree wind direction variation between FS (wind speed and direction displayed in LittleNavMap) and the CRJ. For example, in flight now, I am seeing 238/51 displayed on the CRJ screen and it indicates 254/51. The windspeed is always the same, but the direction always varies by the 14-16 degrees. I have no idea if this has anything to do with the hunting behaviour, but thought I'd mention it. Thanks.

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1 hour ago, acbent123 said:

I have noticed lately that there is about a 14-16 degree wind direction variation between FS (wind speed and direction displayed in LittleNavMap) and the CRJ. For example, in flight now, I am seeing 238/51 displayed on the CRJ screen and it indicates 254/51. The windspeed is always the same, but the direction always varies by the 14-16 degrees. I have no idea if this has anything to do with the hunting behaviour, but thought I'd mention it. Thanks.

What's the magnetic deviation where you're flying, out of interest?

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  • Deputy Sheriffs

Looks like time for another time out for this thread. It will be unlocked once everyone has had time to cool off and simply patiently await work and reports on progress. No news is by no means an indication that nothing is happening on fixes. 

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  • Deputy Sheriffs

Unlocked (again). Let's ALL try to be civil. No need to restart old arguments, as everything that needs to be said on both sides (and a great deal more) has already been said.

 

Thank you!

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  • Herman unlocked this topic
On 5/27/2022 at 12:04 PM, Herman said:

Unlocked (again). Let's ALL try to be civil. No need to restart old arguments, as everything that needs to be said on both sides (and a great deal more) has already been said.

 

Thank you!

Thanks, Herman.

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ILS/NDB procedural approaches seem to be kryptonite for MSFS autopilots at the moment - I've been flying the 146 a bit & noticed some wierdness, so I tried it into EGJJ ILS26 ( which tbh is almost identical to EGTE's ILS26, and quite a few other approaches in the UK at least ). Here's the LNAV part of the plate from current Navigraph AIRAC -

Untitled-12.thumb.jpg.c156d2db9105ca169617deef3a9835fb.jpg

 

Flying these back to back, same wind on runway heading more or less

 

* C310 with the PMS50 750 did probably the worst, although at least it stayed in airspace - left alone it did a circle & a half after initial fix, I'm not really sure why other than that it didn't really turn tightly enough & came into the intercept from slightly north. Was about 5 deg off course though, so no excuse.

* 146, and the WT CJ4 - which share the same FMS - both overfly the initial fix, get halfway to the first waypoint and then turn right to go to the second one. Tried without & with the 5% roll nullzone we worked on here.

* CRJ - flew it well, if inelegantly ( with the 5% nullzone ). Turned left from second waypoint until it was pointing at the third rather than flying the corner, which isn't ideal because it can lead to overshooting the ILS lobes but worked out fine in this case. I know it only has two bank angles, but would the real one stop turning halfway round until a second turn would put it on a proper intercept? it did happily fly the LNAV side of a RNP AR approach with curves all the way ( see other thread ), but that one had waypoints all the way down it.

* WT3000 equipped Longitude ( with the little tweak mod ) tracked the corner perfectly.

* PMS50 530 equipped BN-2 flew the corner properly - that's the only one I've tried with that AP & it's got some pretty vicious PID settings. Would have preferred a jet with one so I could fly the same speeds, but I don't appear to have one.

Edit: as expected, FBW 320 - about which I know next to nothing & basically made educated guesses about - absolutely nailed the approach. That one's source code is available too, isn't it?

 

What is different about the AP in the WT CJ4 to whatever AP the WT3000 and the PMS50 530 uses? source for both WT options is available - I haven't studied it but I bet someone here has. May be clues in there for errant LNAV behaviour? perhaps it's actually an asobo API issue?

 

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My crj has been behaving a bit better lately. It will still undercut a waypoint and and hunt for it a bit, but not as bad as before. On STARS, I have regulated my speeds much more tightly and it has performed better. Also, winds in FS live weather seem more consistent, so maybe that's helping too.

 

On another note, I still can't get the CRJ to acquire the first waypoint in the fmc flightplan. It will always fly toward the 2nd waypoint, so I have to use the heading bug. I thought I heard that there is a way to move the first waypoint down in the list so that it can then be used as a DIR-TO waypoint. Can anyone help me with that? Thanks in advance.

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2010 ? I thought the sales pitch talked about “completely remade for fs2020” and jot being a port ? 

 

also please keep in mind this issue is happening since MARCH 2121 … now its june 2022 though 

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  • Deputy Sheriffs
25 minutes ago, DGH said:

2010 ? I thought the sales pitch talked about “completely remade for fs2020” and jot being a port ? 

2010 means that the CRJ IRL is a 2010 aircraft and not as modern as a recent Airbus.

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2 hours ago, mopperle said:

2010 means that the CRJ IRL is a 2010 aircraft and not as modern as a recent Airbus.


Ow i see

 

i must be mistaken by the first flight in 1999 and first commercial flight for the CRJ 700 in 2001 then …

 

and the first flight of the a320 in the 1980’s …

 

apologies for being dumb 

 

not sure what a software bug with wobbling LNAV and missing waypoints has to do with being from 2010 in real life . 

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2 hours ago, mopperle said:

And therefore you downvoted me? Think you need some time off.

 

I sincerely hope you did not just pull out the banhammer because you got a downvote for apparently being wrong? If so, it might be you who needs some time off.

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  • Deputy Sheriffs

Yes, I took out the limited banhammer. I just wanted to clarify what Mathijs meant. But the attitude in DGHs post was quite obvious. And this ends the discussion.

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On 6/6/2022 at 6:47 PM, Mathijs Kok said:

Part of this is addressed in the update that is being tested. Keep in mind this a 2010 aircraft and not a 2022 Airbus though.

The FBW FMS seems to synthesize intercept waypoints, I don't know what the more default based ones do. For some reason flights into my local airport have been using the ILS approach today instead of RNP ( everything on the ILS app goes over me as opposed to only certain flights on the RNP app, so the noise made me look! ) - the approach is very very similar to that last one I used, and some of the real aircraft appear to cut the corner too ( mostly ATRs ). I think it's fine as long as there's no overshoot - that's not really the time to fly out the other side of the lobes - except of course if the real thing does something else.

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  • 2 weeks later...

OK, there's one that triggered constant overshoot no matter what I did ( fiddled with the stick profile a fair bit too ) -  EGPEDCT STN DCT ODPEX DCT ORTAV DCT ASRUN ASRU1H BIKF ( simbrief handed me that one). ORTAV to ASRUN is a very long way, and the -900 just would not settle at all, I stuck it in HDG in the end & tried at various points to put it back in NAV & it only settled down in the last 30 miles or so.

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7 hours ago, Richard Dastardly said:

OK, there's one that triggered constant overshoot no matter what I did ( fiddled with the stick profile a fair bit too ) -  EGPEDCT STN DCT ODPEX DCT ORTAV DCT ASRUN ASRU1H BIKF ( simbrief handed me that one). ORTAV to ASRUN is a very long way, and the -900 just would not settle at all, I stuck it in HDG in the end & tried at various points to put it back in NAV & it only settled down in the last 30 miles or so.

I've used heading mode a fair bit too. It's fine if you don't have a strong crosswind component, but it you do, you're soon far off course, or you're having to make constant course corrections. One time, with a +/- 100 kt, nearly perpendicular crosswind, I ended up almost wrapping around a waypoint in an attempt to cross it. 

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28 minutes ago, acbent123 said:

I've used heading mode a fair bit too. It's fine if you don't have a strong crosswind component, but it you do, you're soon far off course, or you're having to make constant course corrections. One time, with a +/- 100 kt, nearly perpendicular crosswind, I ended up almost wrapping around a waypoint in an attempt to cross it. 

Which is why you don't stick the heading bug on the waypoint, but still fly using your instrument of choice to stay on track. The wind on my run varied from 75 to 150kts with varying crosswind componnts, so it certainly wasn't a case of just sticking it in HDG & leaving it. The CDI bar is pretty handy.

 

I don't generally have to resort to HDG, this is the first time in a long time, and I can't remember the last time I had to use HDG for so long.

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vor 2 Stunden schrieb Mathijs Kok:

I suggest to test this again when the update is out. could be any moment now.

It is always worth a test, but it was told that the LNAV behaviour issue is not fixed in this update.

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3 hours ago, Richard Dastardly said:

Which is why you don't stick the heading bug on the waypoint, but still fly using your instrument of choice to stay on track. The wind on my run varied from 75 to 150kts with varying crosswind componnts, so it certainly wasn't a case of just sticking it in HDG & leaving it. The CDI bar is pretty handy.

 

I don't generally have to resort to HDG, this is the first time in a long time, and I can't remember the last time I had to use HDG for so long.

I guess I should have clarified that I don't aim the heading bug directly at the waypoint, but corrected for wind component. Wind shifts and increase or decrease in speed changes obviously affect heading and adjustments are needed. I am inflight now CYFC to CYYZ and the crj is really acting up. I took 10 - 12 oscillations back and forth to finally acquire the track for my first waypoint  - worse than it's been in a long time actually. Who knows, maybe this update will help things. 

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38 minutes ago, acbent123 said:

I guess I should have clarified that I don't aim the heading bug directly at the waypoint, but corrected for wind component. Wind shifts and increase or decrease in speed changes obviously affect heading and adjustments are needed. I am inflight now CYFC to CYYZ and the crj is really acting up. I took 10 - 12 oscillations back and forth to finally acquire the track for my first waypoint  - worse than it's been in a long time actually. Who knows, maybe this update will help things. 

The first WP has always been problematic, that *is* one I've usually flown in HDG. Not aquiring track halfway through the flight is really uncommon though.

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1 hour ago, Richard Dastardly said:

The first WP has always been problematic, that *is* one I've usually flown in HDG. Not aquiring track halfway through the flight is really uncommon though.

I'm not doing a very good job explaining things today. My first waypoint, I usually fly to with heading mode as the FMS usually automatically selects the second waypoint to track to. Maybe the pic below will explain things better than I currently am. I let LNAV take me directly to CANME. The plane sharply undercut the turn, then hunted back and forth, as mentioned, 10 - 12 times before finally acquiring the on course heading. The dotted line I'm guessing is not sensitive enough to show the deviations left and right. Sometimes I find that engaging 1/2 bank helps to keep the plane from undershooting or overshooting, but it was really badly behaved today, unfortunately. The approach to ILS 23 was better, but it still swayed back and forth a few times between waypoints.  

YFC - YYZ.PNG

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