FSX-MS AI in circuit break ranks and run for the hills (literally)

[JonP01 104]

I have been on a Winter project hand-making AI for those airfields where the stock plans either do not exist or they were third party add-on airports with no traffic to begin with. Everything seemed to work fine with the stock airports, though with those I did not really do anything much more than add flights between airfields and in some cases added touch and goes at the destination airport to fill in time if they ran "early". All the testing on these worked out fine.

But with my third party airports (coincidentally or not) I am having great trouble getting the AI to simply do touch and go circuits. I have tried all sorts of "workarounds" but get the same result. After about 20 minutes to half an hour - despite being capable of continuing their circuits and not having fuel or other problems, they see to abandon the circuit altogether, fly away and just keep flying....presumably till they run out of fuel 600 nm away....

I have even "copied" the exact method used by the ORBX traffic add-ons for aircraft doing circuits on their airports I own and even tried to add traffic at those ORBX airports. Same problem (though it happens also with their AI). Again, airport to airport plans are flawless.

I have also had the problem "trigger" if another aircraft is coming into join the circuit from another airport - suddenly the AI doing existing circuits seems to think it has been bullied out of the circuit and again runs for the hills, never to turn around. I have even managed to "break" a circuit if I am following an AI aircraft in close proximity, so I believe this might be what is happening. Yet we are only talking about three AI aircraft at any one time - these are not busy airports to begin with.

The only work around I have found is to add one flight plan for every 19 minute "circuit" which is the default circuit time used in the AI Flight Planner traffic utility.

So in summary:

1. All my airport to airport flight plans work fine

2. All my airport to airport flight plans work fine even when adding touch and goes at the destination airport

3. I cannot get aircraft doing ONLY touch and goes to work for more than about 20 minutes to half an hour. They just scamper off into the distance.

4. It is not due to a lack of parking spaces.

5. I am fully aware of aircraft "limitations", making sure the chosen aircraft can handle the terrain, runways, runway length, altitude and that time ia allowed to complete flight plans allows for weather conditions, traffic build-up, etc.

5. I am seeing this happen systemically - even on "official" traffic files - but you have to sit there and monitor the aircraft for a while to confirm when a flight plan "breaks itself".

As I say, my "workaround" sort of works only because if a flight plan is "broken" a new one will take its place within half an hour. I am really wondering whether this is just a limitation / bug within the FSX AI engine and that people do not necessarily notice because they still see the skies full of aircraft and aircraft still doing circuits. But they are only doing circuits till their flight plan "breaks". And once that flight plan "breaks", it will not renew again until the chosen cycle starts again.

Edited July 27, 2021 by JonP01

[JonP01 104]

Well after several days full time on this issue I am now convinced it is either an unresolved bug in FSX (FSX SE) or a deliberate "bail out" in the AI engine code so that if there is some conflict the AI engine cannot resolve, it simply flings the offending aircraft into indefinite straight line flight.

It only seems to happen when the aircraft is instructed to do nothing apart from touch and goes for a sufficiently long time that another aircraft impedes it's ability to use the standard circuit pattern without making leg "corrections". You would think at worst in the case of such a conflict it would variously extend the downwind / upwind legs or at worst do a missed approach but it doesn't even do that.

Thankfully it does not happen (so far as I have been able to tell) if you instruct the AI to simply do some touch and goes at the end of the flight if it arrives early and it definitely does not happen - ever - if you simply tell it to do the standard "19 minute" taxi, circuit, landing and taxi back.

And this is not just a problem with my own files - I've been testing other files and packages and exactly the same thing happens. There are probably a fair number of traffic files out there where not all the flights actually happen or are otherwise truncated or broken.

It would be interesting to see if this still happens in P3D.