FSXA What can make AI planes on IFR ignore coded ILS approach?

[theFiddler]

Hello All,

my problem with AI this time is about forcing AI planes to land on a specific runway, and take off in the opposite direction.

Here is what I am trying to achieve
(in fact, I have achieved it on a test airport, but not where I really want it):

• fictitious airport (actually seaport on a lake, but runway and taxiways are concrete),
  so conflicts with Stock airports are not an issue.
• single runway 04/22
• the snag: there are mountains to the NE, therefore:
  • all landings must be on R04
  • all take-offs must be on R22
• winds are assumed to be calm, so tailwind etc is not an issue
• weather could be VMC or IMC (but no wind)
• user aircraft requirements can be ignored
• runway and taxiways are properly connected etc (OK as per ADEX Fault Finder).
• an appropriate parking spot is available.
• only one (fake) ILS approach created, for R04.
• there is only one flightplan (AIFP3) for one aircraft; this flight is set up to be IFR

What actually happens is that regardless of what I try, the plane (which comes from an airport to the north-east) flies straight in from the north-east, tunnels through the mountains on the way, and lands on R22, ignoring the (fake) ILS procedure for R04 completely.

What I have tried:

• made an ILS approach (in ADEX) only for R04 ;
  My understanding is that this should then always be used for AI at top priority, regardless of weather;
  and certainly so for all AI IFR flights.
• set runway properties in ADEX so that R22 is blocked for landings, and R04 is blocked for take-offs;
• shifted the IAF so that the AI aircraft does not have to overfly the whole airport first to reach the IAF
  (and thus might be tempted to use the more direct R22 instead of going the long way round to R04, as per ILS approach),
• tried two different aircraft, in case it has anything to do with a/c performance;
• split the airport BGL into two, one of which (airport scenery etc) going to the Addon Scenery folder,
  the other (which includes the ILS approach) going to Scenery\Global\scenery (as seen in Jim Vile's examples)

I did study at length both Jim Vile's "Approaches" tutorial (on this site), and Holger Sandmann's tutorial on AI seaplanes (ai_float.zip) but still cannot find out what is going wrong.

The weird thing is that I have tried the same with another fictitious airport elsewhere (on land), and there everything worked fine.
Apparently just the "blocking" in the runway properties was enough to force landings on one runway only, even if that meant a 10 kn tailwind...
(The fake ILS approach there also worked; it was used to make a curved approach.)
Correction: On next test, the same problem at this airport: AI (IFR flights) land on R09 even though the only available (fake) ILS approach is ILS27, and R09 is blocked for landings in runway properties. Even when there is no wind.

My question:

• Which other factors can cause an AI aircraft to completely ignore the sole ILS04 approach coded (via ADEX) in the airport BGL,
  and land in the opposite direction (R22) which should be blocked for landings anyway via ADEX runway properties?

Thanks in advance for any pointers.

Cheers,
Martin

 

[tgibson]

I have occasionally seen this happen, but cannot make it happen reliably...

 

[theFiddler]

Thanks, Tom!

I think I have found a (the?) solution, but it would need further testing to be certain (in fact a whole and very time-consuming series, if it were done properly):

So, for what it is worth, here is what I seem to have found:

If only one of the four "blocking flags" in ADEX (YES/NO, for take-offs and landings on the primary and the secondary runway heading) is set to "NO", apparently the coded ILS for that runway is completely ignored.

In my case, I wanted landings (but no take-offs) on R04, and take-offs only from R22 (but no landings).
So I set these Properties on the ADEX "Runway/Pattern" tab:
for R04: Landing YES, Takeoff NO
for R22: Landing NO, Takeoff YES
...which seems logical.
Besides, the only coded approach available for this airport was ILS04.

Nevertheless, the AI insisted in landing on R22 (which means boring through mountains on approach).
It did this even when the AI plane had to make a detour to go for R22, i.e. when R04 would have been much more convenient.
(All this was in VMC with no winds, so I have no idea why R22 was preferred. It was in fact set as the "secondary" runway heading, R04 being primary.)

(Interestingly, I also tried with the user plane to see what ATC had to say. I was actually vectored to the ILS04 approach all right, but was then told to make a circling approach and land on R22...)

After changing both NO "flags" to YES, the ILS04 procedure was then suddenly honoured as expected.
Replacing only one NO (for R04) was not sufficient, it had to be both NOs.

I have not been able to find any confirmation that these "flags" are honoured by AI traffic at all, but it seems to be something to watch out for.

And I still have to see what runway will be used for take-offs.
I don't know even in theory how to force AI take-offs from a specific runway; AFAIK no "procedures" can be coded for that at all.

As always, YMMV applies...

Cheers,
Martin

 

[tgibson]

AI will take off from the active runway who's extended centerline is closest to the plane's parking spot. I don't know how to change that.

Those flags are honored by AI, but only if there is another parallel active runway that is not flagged as NO.

 

[theFiddler]

AI will take off from the active runway who's extended centerline is closest to the plane's parking spot.

Ah yes, that applies exactly to my case.
Important info, thanks!

Cheers,
Martin