FSX AI Arrivals Anomaly

Hi folks - could someone help me out here. I don't think this is an AIFP bug, just something I (probably) don't understand about FSX AI.

I have the AI at my (UK WW2) airfields set up so they do a quick air test (take off, fly a circuit and land at the same airfield) in the morning, then fly out on a 'mission' (actually to an airport in Europe) and then return. Three legs per flight plan/aircraft. For example I created the following plan using AIFP 1.6.33:

(1) 09:00,09:19,20,R,121,S365
(2) 12:00,13:38,20,R,121,EDDK
(3) 14:00,15:38,20,R,121,S365

This plan has John Young's B24 flying out of Ian P's Halesworth (S365) and undertaking a mission to Cologne (EDDK).

If I position myself at EDDK and run this plan in real time, everything is OK - the a/c arrives and takes off at the appointed time.

However, if I position myself at Halesworth, odd things happen. The air test at 09:00 is fine. So is the takeoff at 12:00. But at 14:00 (the time that the a/c should be taking off from Cologne), it appears on both the Air Traffic View and Traffic Explorer about 23nm from Halesworth. It then requests landing at 14:07 and touches down at 14:16, nearly an hour and a half before it is due !

I've experimented, and find that if I start my flight at Halesworth any time between the time the a/c should have taken off from Cologne and the time of arrival - the a/c immediately appears on Air Traffic and Traffic Explorer. In fact this is how I spotted the anomaly in the first place - I had a flight of six a/c flying back from Cologne at 30 minute intervals. If I started my flight at Halesworth 90 mins after the first a/c left Cologne, all six a/c immediately appeared in Air Traffic view flying in an intimate formation that would put the Red Arrows to shame !

Now for the really interesting thing - I find that if I delete the first leg (the air test) from the plan i.e.

(1) 12:00,13:38,20,R,121,EDDK
(2) 14:00,15:38,20,R,121,S365

everything else works correctly - the a/c doesn't appear back in Halesworth airspace until its scheduled arrival time.

Can anyone shed some light on this ? It doesn't seem to be aircraft or airport specific.

Thanks !

Last edited:


Resource contributor
What is the source of your two copies of the FP. If the flightplans.txt file, then there is some sort of problem. But they look suspiciously like they come from AIFPs text editor. If that is the case, are you programming on local time of GMT? If local time, the last two legs overlap; 1400 at S365 is 1500 at EDDK.

One thing I did notice, which may or may not be significant. If I display Arrivals and Departures in AITP for the 3-leg plan, the 09:00 departure from S365 does not appear for the first leg, only the 09:19 arrival. Is that correct ?


Resource contributor
And all times are GMT.
Is that just your intent, or have you confirmed Local Time is not inadvertently selected. (Local time is one of the settings that is carried over from one session to the next.)

But if those times are truly GMT, then I can't explain other then to suggest you've found an(other) idiosyncrasy in FlightSim. AIFP has no role in the execution of FPs.



Resource contributor
I have seen certain flight plans that exhibit similar behaviors. I assumed it was an FS bug. As you found, adding or deleting legs often fixes it.
Is that just your intent, or have you confirmed Local Time is not inadvertently selected. (Local time is one of the settings that is carried over from one session to the next.)
Well - GMT is the option displayed in AIFP, and I recall a while back I went through all my flight plans and changed them to GMT. So pretty sure.

If it's a FSX bug, it's not straightforward to work around. I thought of splitting the plan into two plans, but of course I can't have a plan with a single leg. I'll play some more. Thanks for the responses.

Just an update. I have spent a lot (a lot) of time on this, Here's what I think I found. It does indeed look like a FSX bug.

It looks like the problem exhibits in any flight plan that includes a leg which is a simple circuit, taking off and landing at the same airport, The duration of this leg doesn't seem to be important, merely that the departure and destination are the same. Removal of such a leg from the flight plan removes the problem from all other legs.

The problem exhibits in two basic forms:

On the simple circuit leg - if the user flight begins at the departure/destination airport at any time during the duration of the leg, the a/c appears on the ground and begins its flight (i.e. starts up, taxies out, takes off) immediately.

On other legs - as described above, if the user flight begins at the destination airport at any time during the duration of the leg, the a/c immediately appears in the destination airspace, requests landing clearance and lands. This may be many minutes/hours before it is due.

I doubt this problem will be an issue for many. In my case I've had to have separate a/c do the air tests and operational flights. Not strictly realistic, but it generates the same level of activity.
And it works. Unfortunately by the time I got to understand the problem I have a dozen or more airfields, each with upwards of 25 flight plans that need to be changed. Not to mention some collateral changes required to parking, fuel trucks etc etc. Ho hum.