A350 nonsense VNAV behavior!

[ekosif]

Hello all!

Tbh, I am really pissed off. Each update fixes something but break another thing. Now one of the essential feature is not working properly, which is VNAV!. Last time I've reported incorrect TCAS callouts but no one from ini team had a look at it. Now I am in trouble with VNAV (not happened just one time!). 

During the climb, aircraft stop climbing at random altitude even though there is no restriction or mode/target altitude change. For example, I set climb to FL240 with managed mode, but it stop climbing at FL120, then I push the altitude button, it continue to climb but stops again at FL175... So in order to reach desired altitude, I have to push the altitude knob several times, which is really annoying after some time!

During descend, same thing also happens. I have to push altitude knob several times to descend to desired altitude. Again, no restriction or change on anything! There was not even any point in front of me for next 50 miles!

And also, during approach with ILS, it randomly switches from G/S mode to vertical speed mode, literally for no earthly reason!

A considerable amount of time has passed since the plane was released but we are still struggling with basic and essential bugs. I personally don't have unlimited time so trying to make a flight in very limited time window and do not want to spend my time with this kind of things. 

[frank_m]

12 hours ago, ekosif said:

Last time I've reported incorrect TCAS callouts but no one from ini team had a look at it.

That is not true, there have been several statements from the team regarding TCAS in the past.

Regarding your VNAV Problem: I can't confirm it. During the Christmastime I did a lot of flights with the A350 on random connections (chosen with https://where2fly.today/). There was never an issue with VNAV, neither in occupied areas (Europe, USA), nor in lonely regions (Asia, Africa). Neither with handcrafted airports, nor with standard airports.

I think, either your navdata is not correct installed, or there are conflicts between your flightplan and your navdata. Maybe you are using outdated waypoints somewhere in the chain? Well, it is definitely not a bug of the plane, since otherwise a lot of people would complain about this issue, and you are the only one.

Edited Saturday at 11:50 AM by frank_m

[ekosif]

1 hour ago, frank_m said:

That is not true, there have been several statements from the team regarding TCAS in the past.

I am NOT mentioning about the past statements here, that's not even a valid viewpoint, of course they might mention about the TCAS a few months ago but hey look, still having problem here?

Regarding my VNAV  problem, my navdata is correct and up to date. No problem with PMDG products or Fenix 320 or ini 330, so this one is the only problematic one. Therefore you can not blame the navdata. Flightplan is standart Simbrief flightplan and I've never see any single person had conflict in that. And I clearly indicated above that there were no waypoints for next 50 miles (no direct to as well).

You said a lot of people would complain, but here is the one item from last update:

Fixed - WASM texture loading bug introduced in SU4 on some machines
As you can see, some bugs do not occur on every user. I don't know how you can say this is DEFINETELY not a bug but let me say it very clearly, I don't think you are the person who decides it is bug or not.

Let me summarize it for you again, if your simulator and all other systems and addons work without any issue with the other aircrafts but not with the A350 then you can consider it as a product bug. I am a SW engineer with master degree, if your SW is not working on all of your target systems or platforms then you are doing something wrong on fail catching or management and you are not robust against different noise factors and that is also a BUG!

[frank_m]

3 hours ago, ekosif said:

I am NOT mentioning about the past statements here, that's not even a valid viewpoint, of course they might mention about the TCAS a few months ago but hey look, still having problem here?

Yes, there is a problem and a recommended configuration to circumvent it as long as they are working on it. What else do you want? 

3 hours ago, ekosif said:

Flightplan is standart Simbrief flightplan and I've never see any single person had conflict in that.

Oh, I have. In particular, people using outdated Navdata in Simbrief are creating invalid flightplans.

 

3 hours ago, ekosif said:

Fixed - WASM texture loading bug introduced in SU4 on some machines
As you can see, some bugs do not occur on every user.

Oh, that problem occurred for the large majority of the users. Additionally it was confirmed by the team. Your "bug" is observed by only one user and not confirmed.

3 hours ago, ekosif said:

I don't know how you can say this is DEFINETELY not a bug but let me say it very clearly, I don't think you are the person who decides it is bug or not.

It becomes a bug if enough people are complaining about it, and it is confirmed by the team. Which both is not the case for your problem.

3 hours ago, ekosif said:

Let me summarize it for you again, if your simulator and all other systems and addons work without any issue with the other aircrafts but not with the A350 then you can consider it as a product bug.

No, that is definitely not the case. There may be problems caused by addons causing problems in specific other addons, but not in all. Think about the problems caused by addons having no "package_order_hint" entry in particular with Navdata. It looks like a problem of the plane or the scenery, but finally it turned out to be a problem with the Navigraph Navdata caused by old MSFS2020 sceneries not involved at all in a specific flight. It is enough if the old addons were installed to disturb the navigation.

3 hours ago, ekosif said:

I am a SW engineer with master degree, if your SW is not working on all of your target systems or platforms then you are doing something wrong

Oh, I'm sorry about that. Then you have never developed software for Operating systems the user can configure in an open way and install other software. Otherwise, you would know, how external components can influence the behavior of your software. Just let other tasks consume the resources like CPU or memory and lets see, how good your software performs with missing resources. A problem of your software or of the user not providing a clean environment?

[ekosif]

OK, I don't understand why you are trying to argue with me but let me make one thing very clear for you; you are just blog member and you are not in a position that you can say it is definetely not bug or it is bug, you can advise if you have anything to help to others. You don't have the details neither their backends nor details of my case so do not make judgement by yourself on behalf of others.

On 1/3/2026 at 5:19 PM, frank_m said:

It becomes a bug if enough people are complaining about it, and it is confirmed by the team. Which both is not the case for your problem.

Every bug is reported by one person first and then others join it. This can be route specific, livery specific or variant specific and others may not make any flight with that combination. 

On 1/3/2026 at 5:19 PM, frank_m said:

No, that is definitely not the case. There may be problems caused by addons causing problems in specific other addons, but not in all. Think about the problems caused by addons having no "package_order_hint" entry in particular with Navdata. It looks like a problem of the plane or the scenery, but finally it turned out to be a problem with the Navigraph Navdata caused by old MSFS2020 sceneries not involved at all in a specific flight. It is enough if the old addons were installed to disturb the navigation.

As an old habit, I never update two system at the same time to make the debugging easier. So in this case, I only updated A350 without any other update like scenery, addon or something. I exclude Navigraph for that one beucase it is generally very straight forward. On the other hand, after that flight, I made another flight with same route and same addons with Fenix320, without any issue. ( I am not even saying I didn't have that problem before I updated the A350 )

On 1/3/2026 at 5:19 PM, frank_m said:

Oh, I'm sorry about that. Then you have never developed software for Operating systems the user can configure in an open way and install other software. Otherwise, you would know, how external components can influence the behavior of your software. Just let other tasks consume the resources like CPU or memory and lets see, how good your software performs with missing resources. A problem of your software or of the user not providing a clean environment?

I already answered this, so just paste the previous answer:

On 1/3/2026 at 2:03 PM, ekosif said:

if your SW is not working on all of your target systems or platforms then you are doing something wrong on fail catching or management and you are not robust against different noise factors and that is also a BUG!

 

So, as a customer, and let's assume he/she just wants to make a flight without any system knowledge, if all other aircrafts are working OK but this one not then you would chase for the problems for that particular addon, right? (It was a statement, not a question, just in case 😉 )

[frank_m]

22 hours ago, ekosif said:

OK, I don't understand why you are trying to argue with me but let me make one thing very clear for you; you are just blog member and you are not in a position that you can say it is definetely not bug or it is bug

But the same lasts for you. I'm just seeing the facts: no other users complainig about the issue, and I can't confirm it at all. Therfore I tell you: it is a bug when it is confirmed, but not before. 

22 hours ago, ekosif said:

Every bug is reported by one person first and then others join it.

You are perfectly right. And what is missing? The other users joining.

On 1/3/2026 at 2:03 PM, ekosif said:

if your SW is not working on all of your target systems or platforms then you are doing something wrong on fail catching or management and you are not robust against different noise factors and that is also a BUG!

If you ever have developed only one line of code, you know, that this is impossible on systems you can't control completely. Otherwise you have absolutely no clue about SW development. 

[ekosif]

49 minutes ago, frank_m said:

But the same lasts for you. I'm just seeing the facts: no other users complainig about the issue, and I can't confirm it at all. 

You are NOT the person who will confirm it, got it? I've tried to explain it to you politely but obviously there is something you are not able to understand, this is not your responsibility so just mind your own business and let the rest to ini team. If you are having same issue then add your experience. If you have solution, share it with others. Otherwise just read and keep surfing. Don't create unnecessary crowds here.

 

1 hour ago, frank_m said:

If you ever have developed only one line of code, you know, that this is impossible on systems you can't control completely. Otherwise you have absolutely no clue about SW development. 

Yes, I didn't develop just one line of code in my 13 years of work experience. Maybe you teach me some coding and error management. Obviously you have knowledge about everything. 

If anyone from ini team reads this, give this guy a role so he/she can formally approve or disprove the bugs on behalf of you.

[iniSteven]

On 1/2/2026 at 6:41 PM, ekosif said:

Hello all!

Tbh, I am really pissed off. Each update fixes something but break another thing. Now one of the essential feature is not working properly, which is VNAV!. Last time I've reported incorrect TCAS callouts but no one from ini team had a look at it. Now I am in trouble with VNAV (not happened just one time!). 

During the climb, aircraft stop climbing at random altitude even though there is no restriction or mode/target altitude change. For example, I set climb to FL240 with managed mode, but it stop climbing at FL120, then I push the altitude button, it continue to climb but stops again at FL175... So in order to reach desired altitude, I have to push the altitude knob several times, which is really annoying after some time!

During descend, same thing also happens. I have to push altitude knob several times to descend to desired altitude. Again, no restriction or change on anything! There was not even any point in front of me for next 50 miles!

And also, during approach with ILS, it randomly switches from G/S mode to vertical speed mode, literally for no earthly reason!

A considerable amount of time has passed since the plane was released but we are still struggling with basic and essential bugs. I personally don't have unlimited time so trying to make a flight in very limited time window and do not want to spend my time with this kind of things. 

Hi Ekosif - I think we need more information to know what exactly is going on here. I've flown a lot with the A350 over the past few weeks in 1.2.0 and haven't had the issues you are describing with the VNAV.

Would you be able to record a video or take a screenshot when the plan is behaving as you describe?

In the meantime, double check a couple things for me:

• What was the ISA on your climb? Sometimes the sim has a bug where the atmosphere incorrectly remains the same default temperature at all altitudes, and this causes a significant loss of thrust preventing the aircraft from climbing (As would happen if this situation occurred IRL)
• Do you have a keybinding conflict that is engaging or changing autopilot modes? If you have to push buttons several times for them to register, a keybinding conflict could also cause similar behavior.

Best,

Steven

[LineDX]

7 minutes ago, iniSteven said:

Hi Ekosif - I think we need more information to know what exactly is going on here. I've flown a lot with the A350 over the past few weeks in 1.2.0 and haven't had the issues you are describing with the VNAV.

Would you be able to record a video or take a screenshot when the plan is behaving as you describe?

In the meantime, double check a couple things for me:

• What was the ISA on your climb? Sometimes the sim has a bug where the atmosphere incorrectly remains the same default temperature at all altitudes, and this causes a significant loss of thrust preventing the aircraft from climbing (As would happen if this situation occurred IRL)
• Do you have a keybinding conflict that is engaging or changing autopilot modes? If you have to push buttons several times for them to register, a keybinding conflict could also cause similar behavior.

Best,

Steven

Agree with Steven, no issues with the VNAV. Noticed higher  ISA temps do affect the climb performance, which is quite normal. Thanks Steven.