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Mathijs Kok

Not following ascent/descent path

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As there were a few topic that seem to be related we decided to make one topic so we can try to understand what is causing this. Let's start with what we know.

 

  • We have 21 people on file that reported this (that far below one promille of users)
    • 3 have not replied to our attempts to get more info
    • 9 have reported their issue solved
      • 2 by using correct procedure
      • 1 by making sure FPS was high enough
      • 6 by re-installing the sim.
    • Leaving 10 users who still face this (likely there are some more that have not been in contact with us
  • We are unable to recreate this reliable on our systems (other then my making deliberate mistakes in speed management)
  • We know our code has some loose ends that might make the path following a bit sloppy (but not in the degree described), it seems unlikely this is involved in these cases.

 

Because the issue only seems to affect a certain group of users  the difficult task will be to identify what makes these user unique among the total amount of customers. There has to be a local element to this problem. Something that triggers it for these customers.

 

  1. The first thing that we can think of is an incorrect simulator after updating from a previous version. In another issue we have seen this over 70 times and reliably fixed by fixing the sim. It did not work on an updated sim and it did work on a cleany installed sim. That this affects only this aircraft and not others is simple to explain, we are using the June 2018 compilers from Lockheed that absolutely needed the latest version of all files. These new compilers are a big part in what makes this aircraft so light on FPS so we don't even consider going back (and it would cause more issues with bugs that Lockheed fixed). As said we seen another far more common issue (the st elmo's fire bug) that is reliably fixed by a correct clean install of the sim. That proofs the updated files where not correct.
  2. Next to the sim files option, the second most likely cause is frame rate. It all can be explained when framerates drop below our 16 fps threshold, even for a short moment. When the FBW system gets upset by that it can start to hunt itself. This was the case for the single user reported above. He had the issue consistently and had relative good fps, but when he increased the FPS the issue was avoided. Most likely short low fps moments caused the issue. 
  3. The next possible reason is user error.  Speed management is not the easiest thing in an Airbus and often overlooked as a factor for problems. Also abnormal loading could cause issues. For two users this was most likely the issue. One had incorrect settings in MCDU, the other did something else wrong that we still do not understand,
  4. A possible cause is jittery controllers, we seen that a few times in other products and would explain why this happens to so few users.
  5. The last cause could be weather. Some weather tools insert rather violent changes in wind patterns (and often very thin layers and very small 'blocks' of weather. our busses have always been rather sensitive to this. Strong changes in IAS cause strong changes by the FADEC and when the aircraft hits another layer before things have smoothed out the aircraft systems can get overloaded. It should happen far less than with previous releases but still a good possibility.

 

At this moment we do not have any changes that could affect this behavior planned for the simple reason we do not know what to change. The loose ends in the code will be fixed with SP1 but as said we do not think they are related to what these users see. They will only smooth out the movements and make it stick a bit better to the profile. 

 

-----------------

 

The users who still have these issues could do us a huge favor and fly the step-by-step flight (following all steps), with zero weather and very low scenery settings. If that solves it for some we are one step closer to understanding what is happening. This flight has been flown by us hundreds of times so it is the best benchmark. If you do see problems please let us know EXACTLY at what step.

 

in the end I am sure we can solve the issue for most users, but as always there will be some occasions that we'll never understand. We have had that with every product. In those cases only a complete format of the disks is the solution. Far from ideal, I agree, but it would mean you have a 99.99% chance of being one of the tens of thousands of users who don't have the issue.

 

I do thank you all for being patient and cooperative. We absolutely understand it can be frustrating, also for us. We want you to enjoy the product after all.

 

 

 

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Well, this happen every flights below FL100. Nose up and very high angle of attack if using management mode in autopilot. I have a clean install (all) and windows too. This is not happend ever in 32bit busses.

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Ok Mathijis;

Would it be possible to please get a refund for this product? 
Thanks, 

 

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1 hour ago, MikaV said:

Well, this happen every flights below FL100. Nose up and very high angle of attack if using management mode in autopilot. I have a clean install (all) and windows too. This is not happend ever in 32bit busses.

 

Okay then you are clearly one of the ten (eleven by now) reported cases.  As it does not happen with tens of thousands of other users we just need to find out what is different in you system. At this moment I simply have no idea.

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1 hour ago, A340-4 said:

Ok Mathijis;

Would it be possible to please get a refund for this product? 
Thanks, 

 

 

We could consider that for sure if we find an error in the code that we are willing or are unable to fix. But again as it seems this is limited to a very small amount of people it simply does not seem likely the code is faulty. I just watched all the YT vids I could find and on none of those the aircraft was unable to follow the path.

 

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Btw I find it very strange that people vote my post down. I clearly and obviously try to work constructively towards a solution for an issue that we have (almost certainly) no control over. 

 

If this was a bug in the code there would be tens of thousands of people complaining. Right now we have eleven. If we all work together we probably can bring that number down. 

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1 hour ago, MikaV said:

Well, this happen every flights below FL100. Nose up and very high angle of attack if using management mode in autopilot. I have a clean install (all) and windows too. This is not happend ever in 32bit busses.

Very high Angle of Attack or Very High Pitch attitude, there is a difference!

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Here is another poll from a different group: 

Sorry, but a little more users are having issues than what you guys might think. 


image.thumb.png.8dae3ec94762120b36aa56631ccddf10.png

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I also got this issue as well.

I updated to P3D v4.3 using the update instructions from LM, rather than fresh install.

 

Aircraft actually hit 10,000 FPM descent.

I was descending into Barcelona from 30,000 feet using MATE2J STAR.

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2 hours ago, Mathijs Kok said:

 

Okay then you are clearly one of the ten (eleven by now) reported cases.  As it does not happen with tens of thousands of other users we just need to find out what is different in you system. At this moment I simply have no idea.

 

I'll think customers thinking like me. This is not fully ready airplane, there will be service packs and hot fixes. So customers like me, waiting those improvements and don't tell every bugs or abnormalities...

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14 minutes ago, MikaV said:

 

I'll think customers thinking like me. This is not fully ready airplane, there will be service packs and hot fixes. So customers like me, waiting those improvements and don't tell every bugs or abnormalities...

 

Mika,

 

Based on your comments, I have to assume that you are new to the flight sim community and you are unfamiliar with flight sim development and the development of other products by other developers as well as this one.  That's okay, you'll learn as you gain more experience in the flight sim community and when you do then you'll understand how things work in the flight sim community.  If you don't want to wait, and you want to instigate change, then I recommend approaching the owners of every single company in the flight sim community because your comments apply to them as well.

 

Best wishes my friend.

 

 

 

 

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Yes I am new in this forum, but I flying Aerosoft busses many years before new 64bit busses. I never ask nothing in here, because i don't have any problems. Okay there was an few, but I get my answers from Finnish forum in my own language. Also I don't know development so much (this kind) or nothing. I working with computers and education, so of course I know something about development in my sight. I am flying simulators since 1991, so I see a lot of simulation. Also I don't instigate nothing (if you see this in that way, I apologize) I'll think it's maybe issue from my bad English language (I'm using wordbook every period into this text). I also don't demand to you hurry up for complete done Airbus because there is no point at all! I'm just trying help you when I tell you some problems.

 

Afterwords: Maybe this helping? In older busses shortly after takeoff, the flight director guide me to lower pitch (which is normal procedure). The new bus flight director guide me to raise pitch (this is not an normal procedure). So i do that like before, I lower pitch, climb 1000ft and connect autopilot on. I reached thrust reduction / climb altitude 1180ft (1180 above ground level in Helsinki airport) and made thrust reduction (CL mode in thrust levers). Now the plane (actually imminently after autopilot connected on) raising pitch even 99 degrees if I don't do nothing (select attachment mode). 

 

Regards: Mika.

  

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Can I kindly ask if people would follow up on my advise so we can make some progress?

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15 hours ago, A340-4 said:

Look here: https://www.facebook.com/groups/p3dgroup/ 

There is a little more than the eleven people. 

Edit: I will save you the trouble and paste it myself. 

If you are interested you can also read the comments.... 

 

I have seen these comments and if these people (those that are not there AND here) follow up with us here we might get a better idea of what is causing that on their systems. Of course there are probably more people but people who do not contact us can't be assisted by us.

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7 hours ago, Mathijs Kok said:

Can I kindly ask if people would follow up on my advise so we can make some progress?

Hello;

Whats your advise? 
If you are asking me to nuke Windows together with my P3D and star everything from scratch- I wont do it, sorry. 

If you want me to run the Bus with the "test flight" I will be giving it a try. 

Please advise. 

Thx. 

 

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Well we are 99% sure a clean system will solve the issue but I understand you do not want to go that way. For now trying the Step-By-Step flight at very low display settings would be very helpful. I just had a mail from a person who could not see the issue in those conditions so we are pretty sure FPS is involved there.

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steep descent rates workaround?

I also had the problem with ascent/descent rates exceeding 5000-6000 fpm and was not able to conclude one smooth approach and landing but didn't post anything as I wanted to investigate this issue. Just to be sure that not a mistake/configuration issue on my side is the cause (weather engine, joystick etc.). 

As I have P3D V4.3 since 1st of Aug. as a complete fresh/clean install I can definitely eliminate an update of P3D as root cause. I tried several things but nothing improved the situation as I discovered that with CI 50 the speed for the managed DES was given with 332. This seemed  too high for my opinion so I tried the following:

For TO and cruise I used a CI of >50. This smoothens the TO/climb phase a little bit. Still excessive climb rates but not that crucial.  Before T/D in the PERF DES page I set a CI of 20 or less to achieve a DES speed of sthg. between 275-300. The FMS tells you then to manually set this new speed in the MCP but after that you can push the knob again and - bingo I had a managed DES with normal 2200-2500 fpm. I tried this 2 times and it worked on routes where before no normal approach was possible. Don't know if this contributes something to the situation but for me it seemed to work.

br

Mark

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10 minutes ago, boss128 said:

steep descent rates workaround?

I also had the problem with ascent/descent rates exceeding 5000-6000 fpm and was not able to conclude one smooth approach and landing but didn't post anything as I wanted to investigate this issue. Just to be sure that not a mistake/configuration issue on my side is the cause (weather engine, joystick etc.). 

As I have P3D V4.3 since 1st of Aug. as a complete fresh/clean install I can definitely eliminate an update of P3D as root cause. I tried several things but nothing improved the situation as I discovered that with CI 50 the speed for the managed DES was given with 332. This seemed  too high for my opinion so I tried the following:

For TO and cruise I used a CI of >50. This smoothens the TO/climb phase a little bit. Still excessive climb rates but not that crucial.  Before T/D in the PERF DES page I set a CI of 20 or less to achieve a DES speed of sthg. between 275-300. The FMS tells you then to manually set this new speed in the MCP but after that you can push the knob again and - bingo I had a managed DES with normal 2200-2500 fpm. I tried this 2 times and it worked on routes where before no normal approach was possible. Don't know if this contributes something to the situation but for me it seemed to work.

br

Mark

 


Hello Mark... and thanks for the info.

 

Please try a flight with CI=30 and ensure you update the wind data for climb, cruise and prior to descent.

 

Looking forward to hearing back from you.

 

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Mathijs, which flight do we need to fly with low settings? Any special route? 

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Hello guys,

 

I have a question for people experiencing this, are you using time acceleration by the time you hit the TOD? I am have been trying to replicate the issue all week.

 

I was able to replicate the problem minutes ago by using time acceleration (x4) during descend above FL240 for 30 seconds and returned to X1, my descent rate went crazy by using the managed descend profile and reached 5000 fpm.

 

Just some thoughts..

 

Regards,
Simbol

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Well, without time acceleration and all types of weather, also clear skies, and many load types and CI’s, -from almost empty to full-, the bus climbs really really fast every flight I did. In all situations. I believe that the A319 is capable of do such a high pitch climbs (for me always between high 3000 to almost 6000vs after TO and Managed climb) but I can not imagine the A321 doing so. I haven’t got any stall or problems with it, so I’m not really sure if there’s any problem regarding this. But yes, maybe the little bus is too much “agile” for me. Can’t say if it’s like the real one though. Can’t remember exactly, but I think that the 32 were much “softer” with climbs and descents, at least I can not remember having issues with it.

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If i made thrust reduction / acceleration before pressing autopilot on, (thrust CL mode) the behaving is more conservative than other ways. I'll think it's still too much pitch.

1808 EFHK - EDDT 01 climb.jpg

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1 hour ago, MikaV said:

If i made thrust reduction / acceleration before pressing autopilot on, (thrust CL mode) the behaving is more conservative than other ways. I'll think it's still too much pitch.

Mika,
 

You are always supposed to climb with the trust level in CLB, from the picture you posted your are climbing in OP CLB (Open Climb) were the flight management system will not follow any altitude restriction constrains in the flight plan and departure way-points, in other words you are telling the Aircraft "Climb to FL380 NOW", you are also using "Managed Speed" with auto-throttle, so the aircraft will climb in open mode at 250kts (since you are below 10,000 ft) with the engines spinning at the maximum rate for CLB. 4000 fpm is not outrageous, it is quite realistic in comparison with real world operations under the circumstances you had on your flight.

 

You can set your desired Vertical Speed when you climb on OP CLB mode, with the example you gave in your picture, if you set the VS for example at 3000fpm you will hear the engines throttling down to give you 3000 fpm at 250kts,.

 

It is also important to point out that Pilots in real world operations don't use the Managed Climb mode unless the airspace is totally empty and the ATC has given them permission to climb directly to CRZ altitude as it is well know that the computer on board will have unexpected behaviours with the climb under the MANAGED MODE which can cause problems with ATC, for these reason they control their climb themselves as it helps them to keep the equipment in accordance to ATC altitude restrictions. Managed Climb mode will also be unavailable if you are not following the programmed flight plan, which happens very often as ATC normally provide vectors instructions during the initial and last parts of the flight.

 

I recommend this read which give a good overview of the airbus flight management system: https://hursts.org.uk/airbus-technical/html/ar01s02.html  

 

*** EDIT.

Correction: The user is climbing in Managed Climb, however the rate of climb is not outside of the real world envelope, apologies for the confusion.

 

All the best,
Simbol

 

 

 

 

 

 

 

 

 

 

 

 

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