FMGC Exemption Continue FSLabs A321

Navigation Data General MSFS Data
1

hi,

After updating to 2505 the FMGC Exemption continue fault is back again with the A321 of Fslabs.
This happened with installing the previous airac as well, and the only working solution is to uninstall the product and re-install.
Old airacs are already deleted, and according to the devs it could be a faulty download on navigraphs end making the file corrupted.
Removing and reinstalling airac has no effect.

This was a topic back in the day but it has re surfaced now in the last few cycles as there are numerous reports on the fslabs forum.
Is navigraph tracking this as well or is this deemed a Flightsimlabs issue that they need to solve?

Thanks!

2

Hi,
Honestly, I have no idea what you are saying here. We have no report here nor any in our ticket system, nor has FSLabs contacted us about an issue.

So, to understand where and what the issue is, we need a little more information. For example, which sim do you use?

Possible a screenshot of the issue/message, … that we can try to reproduce.

Cheers
Richard

3

Allright I’ll put some context :slight_smile:

simulator is MSFS 2020.

The FMGC exemtion error specifically surfaced in the P3D era where the accumulation of airacs over time made the product give this error.
This since has been resolved on FSlabs side, with the update of their control center software who would manage this.

Old topic of this error back in the day as example:

MSFS specific:

When updating the airac via navigraph hub, it puts it in a specific folder %appdata%\FSLabs_NavData
Then Fslabs makes some sort of copy as they need the .rom file in a different folder (don’t ask me why) which is fsl-common\FSLabs\NavData (located in the same subset of folders)
This is just the general side of things.

To a few customers of Fslabs it happens that when updating the airac, it somehow generates a fault within the product and there are a few theories as of what this error (which makes the product unusable) causes.

A quote from the fslabs forum (fslabs teammember) : “For a small subset of our customers, our navdata supplied by Navigraph is getting corrupted during download. This could be anything from localised ISP issues, to a transient issue with Navigraph’s infrastructure that services said download. Both situations are entirely out of our control.”

possible solutions given, are the following:

  1. Manually dowload and copy the airac .rom file

  2. Browse to %appdata%\FSLabs_NavData and delete the entire NavData sub-folder
    Browse to fsl-common\FSLabs\NavData and delete the problematic .rom file
    Return to Navigraph Hub, and FSLabs Navdata should now say “Install”. Proceed with the install, and then launch FSL Control Center. This latter action automatically copies the rom from %appdata%\FSLabs_NavData\Navdata to fsl-common

  3. Uninstall airac, uninstall product, install product, install airac

For solution 1 and 2, it seems the fix is hit or miss, sometimes it works but surely not all the time.
Solution 3 is guaranteed to work. however time consuming and not efficient.

The problem described is a tricky one, as there are not much reports of this error, one solution will work on one system but not on the other etc.
As the problem in essence is that the product can’t read the airac i’m very much trying not to point fingers in who is the right person to talk to if that makes sense :slight_smile:

I’m doing my best to make it a bit clear as to what the issues persists of, if you need more please let me know.

thank you!

Schermafbeelding 2025-05-22 224148
Schermafbeelding 2025-05-22 2241481366Ă—723 169 KB

1 Like
4

Hi again,
Thank you very, very much for this detailed report. This is entirely new for us. I have looked at the forum, the ticket system, and our internal communication with FSLabs, but I haven´t found any information about that. So, I´m sorry that you have this issue.

After reading your description, it is doubtful that this has anything to do with our end, and I will explain why I think this:

Our dataset is one SQLite file. When this file is corrupt (regardless of the reason), it can´t be opened, and you get a system I/O error back, not an internal FMGC error as in your screenshot. In other words, this exception is handled by FSLabs, not by us. I also don´t understand what the error message should say: “FMGC Exception. Continue …”?

Second, you wrote about three different “solutions,” and you wrote that #3 is the best and absolutely solves the problems. The question is, why? The download process from our side is the same as for #1 and #2. The file comes from the exact location with the same tool, so … what is the difference between #1 and #2, excluding that you re-install the FSLabs addon?

Lastly, how does this internally work? After building the dataset, a validator tool tries to open each file. It´s only an “open” request, nothing more, but it shows that the file can be opened/read correctly. After that, we compress this file and test the zipped file again to avoid corruption. Last, the Hub rechecks the file with a checksum algorithm.

My theory is that on this end-user system, the file gets corrupt (or in any other state, I don´t know) during the decompression and the move into the correct location. The Hub decompressed the files in the temp folder and moved the file to the proper location—possibly that is the culprit here. That would explain why this is not a general error but only on a few systems. Or the internet connection is unstable, …

Without any background information from FSLabs, I can´t identify any issue on our side. I have re-checked the source and compressed files on our system, and I can install them without any problem, as many other users can too. Please don´t understand me wrong here, but when this is a download issue, it should appear on all systems and not only on a few … The preferred “solution” #3 looks like an internal FSLabs problem, which would also explain why they haven´t contacted us about this “issue” …

Sorry for the ping-pong, but I don´t see anything we can do here.

Cheers,
Richard

5

Hi Richard,

Thanks again for your detailed answer on this.
I will report to Fslabs and see what they say, as i’m only a customer i do not have any insights on the back end of this and unfortunately cannot do more than say help something is wrong :wink:

If i have more updates i will share here as well, also for future reference.

Thanks!

1 Like
6

I have the same exact problem, loaded FSL and got the FMGC exception message. I recently updated my navigraph cycles.

7

Hi, can you please post the link to this note? I have looked around in the FSLabs forum but was unsuccessful.

Thank you very much
Richard

8

Hi Richard,

Link https://forums.flightsimlabs.com/topic/35783-resolved-fmgc-exception-continue/page/2/#comment-281125

It is posted in the msfs topics, so only accessible to msfs customers.
Should you not have access to this specific forum send a dm to matt crick, as he is involved from fslabs on this topic.

Thanks!

1 Like
9

Indeed, I have no access—that’s the reason. Thank you! I will contact Matt. Thank you very much!

Cheers & enjoy your weekend,
Richard

10

Thank you Richard!
If you need anything else do let me know!

Have a good weekend!

1 Like
11

This topic was automatically closed 2 days after the last reply. New replies are no longer allowed.