I'm starting to get CTD after every flight now. Any advice would be appreciated. I'm running MSFS 2020 via Steam. Flying the 320 Fenix. Only other addons I have is GSX pro with a download that helps connect the Fenix and GSX pro. Other than that just using navigraph and simbrief. All scenery is default. Crashes always happen right at the moment of touchdown. Is this a GSX issue? Never had this problem prior to getting GSX. 

GSX on its own can't crash the sim, because it's run in a separate .EXE, and those can't access the simulator memory because it's in another process (unless they attached to it as a debugger or made specific global hooks at the Windows level, and GSX doesn't do anything like that), it's a pure regular Simconnect application doing only normal Simconnect calls in the officially documented way.

However, a problem/bug in the Simconnect API itself might crash the sim if the problematic API is being called, as the SU13 release notes confirmed:

https://www.flightsimulator.com/release-notes-sim-update-13-1-34-16-0-available-now/

Quote

Requesting some data using the NavData API shouldn’t freeze the sim anymore

This means at least before SU13, there were known problems with the Navdata API which could cause a freeze or crash in the sim, so it *might* be possible not all of them has been fixed and it *might* be possible these might be related to the Navdata itself.

GSX clearly needs to call the Navdata API, otherwise it wouldn't be able to read the airport data, especially if the airport is from the Marketplace but, in general, using the Navdata API is better than the old method of reading the airport .BGL, because encryption aside, it provides extra data it's not possible to get from the .BGL anyway, like the jetway positions after they moved.

Now, it would be useful to know with the best accuracy possible what do you really mean by "always happen right at the moment of touchdown", because in that exact moment, GSX is not doing anything with the Navdata, and it doesn't even create any of its own objects, even if you pre-selected a gate in flight.

- Navdata about the airport is read when the airport enters in range, which by default is 3.0 NM out. 

- If you don't pre-select a gate in flight, GSX objects are created only after you select a destination gate, not at touchdown.

- if you do pre-select a gate in flight, GSX objects will be created ONLY after touchdown AND your speed goes below 50 kts, that is to prevent a pause due to the objects being created "right at the moment of touchdown"

That's why it would be useful to know if the "right at the moment of touchdown" is entirely accurate, or it's really happening a bit later, when you speed drops below 50 kts AND you pre-selected a gate in GSX while still in flight, because that would be the only time GSX is doing something shortly after touchdown.

In addition to that, it *might* be possible that a PREVIOUS call to the Navdata API might not cause problems immediately, so the issue might only happen after touchdown. During flight, the Navdata API is queried by GSX if you open its menu in flight, usually to check nearby airports in case you need to pre-select a gate in flight. In the latest version, we added an option to Disable GSX in cruise, to minimize the risk you open the menu in flight for any reason, and bad Navdata or bugs in the Navdata API might cause a crash, so it might be useful to try that option and see if it makes any difference.

Also, try disabling any 3rd party Navdata, and see if there are any changes. I'm not saying the Navdata is surely "bad", but it might be possible that any remaining issues with the Navdata API won't happen unless you have a non-default Navdata set installed, which would explain why they might have gone unnoticed.

Edited November 27, 20232 yr by virtuali

6 minutes ago, virtuali said:

That's why it would be useful to know if the "right at the moment of touchdown" is entirely accurate,

When I say exactly at the moment of touchdown I mean exactly that. The moment my back tires touch the runway. Not later on but that specific moment. 

Also, I do not pre-select gates with GSX. I do consult navigraph charts on my EFB in the fenix

2 minutes ago, red259 said:

When I say exactly at the moment of touchdown I mean exactly that. The moment my back tires touch the runway. Not later on but that specific moment. 

That's relieving, because at that exact time, GSX is not doing anything, not with the Navdata, neither with creating its own objects at the gate (in case you pre-selected in flight)

Edited November 27, 20232 yr by virtuali

I'm wondering if the CTD has something to do when I used 2x speed in the Fenix. Just did a short flight without CTD so maybe it is tied to the 2x speed or the length of flight. Or maybe neither. Doing a JFK-LAX flight in regular time to see what happens. 

Edited November 27, 20232 yr by red259