Please "destroy" out of range (FLYING) AI Aircraft - that are causing FPS decrease, (and eventually CTD ? )

11/2/2020 Still Issue with #5 patch - No Change

11/24/2020 FIXED in #7 ? patch < < < < < < Thank you Asobo


At least we now have a temporary user Fix
Turn off AI Panes, or keep at low level, and every so often when flying:

  • ESC to General & turn AI Planes OFF
  • SAVE
  • Turn AI Planes back on
  • SAVE
  • ESC to continue flying

Note: No need to move sliders, just Disable-Save-Enable-Save

This applies to FLYING AI Planes only.
(Ground Planes are destroyed correctly , if they remain on the ground, and go "out-of-range’)

This may be the cause ?? (It certainly is "Unexpected !!)

You need something like “Little NavMap” to see this, so you can watch the number & distribution of FLYING AI planes in the sim, over time.

Starting the sim, parked at an Airport, AI traffic is generated out to a Square Box range around you. (the number depending on the slider)

OK so far FPS is fine.

Then as time progress, planes fly out of that Box, but still remain in the sim,
More planes fly into the box from outside and start being generated.

Then, over time, especially if you take off and fly anywhere, Planes are generate around your “box”, but those planes are never removed form the sim.

After a time, there are planes EVERWHERE, in my case covering the whole of the USA, as well as crossing the Atlantic.

With this massive increase in the number of AI planes, most of which, are totally irrelevant to me as I fly, it’s hardly surprising that there could not be extra load being placed on the Sim to keep track of them all.

Even if this increased load is not the issue, the Out-of range planes should really have their objects “destroyed”

ie CPU time goes up to handle more AI = Limited my main Thread
GPU says constant, as most of those planes are far away, past rendering range.

Start of Sim 45 FPS


2 Hours later 10 FPS

Maybe there should be a slider for AI Object MAX range

Having a High density around you is great, but if I am flying East Coast USA, why should I care about planes more than a few 100 miles away, or planes flying in California or 1/2 way to Europe!!!

BTW: All this traffic is Internal l MSFS AI traffic, its NOT Real World Traffic or MP traffic… I have that turned off. (In any case, currently Little NavMap CANNOT display MSFS MP traffic - according to it’s developer - wip)

Any way to get an AI Aircraft COUNT in MSFS, or in Little NavMap ???


Update: Restarted sim.,. NO AI Traffic

Start 50 FPS

2 hours later 50 FPS

Conclusion: AI Traffic , over time increasing AI Traffic requires more resources, and therefore can reduce FPS.

AI traffic should be actively LIMITED by RANGE SLIDER
Typically, any other plane outside of Visual range, or outside max Radio range, is Irrelevant to your plane, flying in the sim.

Unless the SIM is being used as a RADAR … a subject I have not seen come up much so far.

Also, I seem to remember from FSX days, programming with Simconnect, the further a plane is away, the higher the simconnect overhead to find and keep connected to that plane . ??
May not be relevant in MFSF

And that’s just Aircraft… I wonder how many Ground Objects are being created as one flys over them, and then never “Destroyed” as one leaves their vicinity ???

I get a picture of flying across the USA, leaving a whole trail of “Awoken Tug Drivers” in my wake, who are now unable to go back to sleep !!!


Looks good to me and your logic is sound. Zendesk it and you should get a reply email that they got it. You need to register on ZenDesk before you create the ticket and post it.

Thanks for the work you put into it! I will have a look at my AI numbers.

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Someone said in a different post that watching the traffic with little Nav map causes an FPS drop exponentially over time and that you should disable AI traffic visibility in LNM to get an accurate representation.

I can see why LNM would cause extra simconnect activity, but with or without LNM, the FPS drops down the same, over time.

The extra load in the Simconnect processing is probably insignificant to the load placed on the CPU, keeping track of and controlling the AI.

It just seems strange because I do not have the same issue and I fly multiple hours per sim session and I have no FPS change. I use live traffic and multiplayer.


Maybe your system has much higher tolerance to CPU load. I am running a laptop, with only a Laptop gen 9 I5, so only 4 cores, with hyperthreading… = 8 Cpus.
The last on is pretty much pegged at 100% when I last looked with AI turned up quite high.

In any case, whats the point of having all the AI, active so far away ? the max range I would expect would be the Center I was flying in, to hear the Occasional center traffic to other planes.
Anything outside that, I am (and should be ) Blissfully unaware of –

Purely from a programming point of view, it seems very likely that the sim is not destroying Object that it earlier created, but now, should be of no further use.

From a purely selfish point of view, I think I have found what was causing “MY” system to get bogged down, and I can certainly now lower my expectations.

Since I mainly want to fly GA, IFR, I am happy with how things are – will be even happier when a good addon developers comes out with some more function GPS equipment.

Come spring 2021, I would hope that most of these issue are behind us, and the big problem then will be resisting Clicking on all the Goodies in the Online Market !!!

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What is your system spec ? I am just running a Acer Nitro 5 … about as basic as you can get, and still meet the Min spec !!!
Now is NOT the time(at least for me) to be spending silly money on out-of-stock High end upgrades :0

I believe I have also run into this issue. I turned real world traffic on and turned off generic models for AI and after about a 00:45 or 01:00 hour flight, I got a CTD. I think what happened was memory exhaustion, so this may be related to (if it is not itself one) a memory leak. I was able to get longer sessions with larger page files - again indicating a memory issue.

Since I did the changes to stop the decrease in FPS over time, my system is now almost 100% GPU limited and no longer Main Thread limited, and I have completely stopped having a single CTD.

ie Turn down/off AI Traffic

I can certainly live without AI, for the time being, until ASOBO fixes the problem.

No AI is far better than slowing Frame rates, ending in a final CTD.

If it takes a month or 2, that’s fine with me… I can see it will take me at least that long to fully master LNM ( Little NavMap) - but at least it will be on a machine that is not crashing every 30 minutes .

So are you confirming my suspicions? I was looking at the map code, and there’s something called npcAirplaneManager, which manages the other aircraft. I don’t see anywhere that it removes the objects from the cache.

The class NPCAirplaneManager in the file SvgAirplaneElement.js calls“GET_AIR_TRAFFIC”) and processes all the objects it finds. If the aircraft are within range of the map they are displayed. There’s no indication that the aircraft are removed. This is also why I was concerned that aircraft in the map, when you’ve looked away, suddenly zoom across the map. This is why I suspected that the sim was caching thousands of data points.

I already opened this bug report, but I didn’t put 2 and 2 together until yesterday.


Impressed – I did not even go looking for any code that would be dealing with the creation and destruction of Simobjects.
I just assumed that it would hidden in some compiled dll in the hidden application area.

So, if you can see the AI simobject code, can you see how creations depend on the AI Sliders, and range from the plane, and possibly altitude.

If that is just for the VFR map, then its getting a sub-set of all the AI Aircraft the sim is actively following, and its that total simobject count that is probaly the main issue.
ie if you zoom in the VFR map to a very small area, it makes no difference, still a low FPS, because the load is not so much caused by the VFR map display just a few simobjects, but by the Total number in the sim, that have been created.

Then what other non-aircraft simobjects are being created , and never destroyed.

It would nice to be able to visualize that on a map, ie LNM, just like you can already for aircarft.
Imagine LNM being able to display , as a debug tool, all Ground Simobject in the sim

I suppose one could infer that this is an issue, by turning AI aircraft to MIN, and AI Ground services to max, and flying across the country over major airports – and seeing if FPS drop over time. ?

I should leave the sim running all day, on a FP between major airports, and see how the FPS are when I get home from work.

I cannot imagine that some of the Beta Testers did not go down this path … but as it is still a possible issue in the sim, maybe they just got “Backlogged” (to put in nicely)

I have confirmed with LNM that AI ground aircraft (not sure about vehicles, employees, and watercraft) do despawn if you go far enough away from them.

Well, the Screen shots I posted earlier would indicate that they do not …

Can you show your LNM evidence - ie some screen shots, that show traffic getting destroyed as they exceed some range

I am really hoping your are right, as failing to destroying out of range objects would be a giant “BooBoo”

Would be really nice, if part of the Developer’s FPS diagnostic windows, could show a count of current SimConnect objects, being processed by the sim…( ideally Aircraft, and non aircraft as different numbers)

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Great discussion! Very constructive, and confirms a suspicion I’ve had. Last week I decided to turn off AI traffic completely. Since then I’ve experienced consistently better frame rates - even at KSFO - and one single CTD event, which I traced to a background process unrelated to Flight Sim.

A slider would be nice, to set a “bubble” around your aircraft.

In the following screenshots I have AI AIR traffic turned off. Only ground traffic is on.

Start a flight; have ground traffic in my area (KMCO)

Fly a little while, ground traffic spawns at a nearby airport (KORL)

Fly a little further, ground traffic despawns at KMCO

I have also see AI boat traffic spawn and despawn similarly.

A Bubble – yes …

Then the discussion becomes, what shape should this bubble be.

AT first consideration, the idea bubble need only be as big as your planes Radio range.
Yo want to be able to hear anyone within radio range, so they need to be there to be heard.

This might work out very well, because the higher you go, the more your range increases, but the else detailed rendering one has to do com paired with at ground level.

Then with that being the maximum bubble, a way to reduce the bubble, if your system cannot handle that volume of traffic withing the bubble.

I would initially assume the would be the to increase density, as opposed to size.

So maybe this results in more than one simple slider control.

Personally, I want a high realistic amount of “distracting radio chatter” without overloading my CPU, so I end up at an optimum state where my CPU & GPU share being the limiting factor, with the GPU mainly being the limiting factor, for a give required Min Frame Rate (I think ?)

That’s great news … so it may just be FLYING aircraft that are causing the issue ?

Certainly, aircraft that are currently flying 100’s or 1000’s of miles away are not need or at all relevant to me in my plane at any part of my flight. !! :slight_smile:


I’m currently sitting on the ground at KMCO with AI air traffic turned up to crazy - slowly watching my RAM get eaten and my FPS drop. My LNM looks like yours.