Hi,I have some questions concerning the implementation of the AI traffic in FS9 but I couldn't find anything related on the web. I hope some of you can help me. After installing the ProjectAI traffic I noticed that in the beginning the aiport (EDDF) is crowded with aircrafts and one after one taxis to the active runway and takes off. However, the first incoming aircraft occurs only after more than 30 minutes and even than landing aircrafts are very rare. So the question is where all the AI aircrafts are generated at the beginning of the simulation? From what I observed I would guess that they are positioned only at airports (and not generated in flight) and therefor it takes some time till they arrive at e.g. EDDF. Then of course the question is at which airport they are generated (as far as I understood a flightplan can have more than two airports) and what about the planes that should be enroute according to their flight plan?Does this also mean that if you have 3000 flightplans FS9 keeps track of all corresponding flights even if they take place on the other side of the earth (in principal a plane could fly from Australia to USA and I could fly from Europe to USA and we could meet there)? Sounds a little bit unrealistic to me.I hope someone can answer at least some of the questions.Cheers Alexander Kappes

Hi,The planes "appear" in flight as well. They are placed up to 100 NM away, depending on the aircraft's weight (it appears - Cessnas are placed closer than 777's). Thus they take some time to get to your airport.All AI aircraft are generated within about 100 NM of your location, so they will appear at many airports in the area.Yes, FS keeps track of them all, to a point. However, the flights are divided into sectors (for a given time period), and it ignores flights it finds that are not in your sector at this point in time.Hope this helps,--Tom GibsonCal Classic Propliner Page: http://www.calclassic.comFreeflight Design Shop: http://www.freeflightdesign.comDrop by! ___x_x_(")_x_x___

Hi Alexander,In addition to Toms reply.....I believe the FS9 AI world is split up into 40 mile squares (I'm not 100% sure on the size). FS9 calculates 9 squares, the one you're in and all the adjacent ones.When it loads the AI traffic, what it is doing is trying to figure out where in the world all the aircraft are. Based on that it then "enables" (starts, uses, simulates, however you want to describe it) all those that are in those 9 squares. My understanding is that aircraft will be placed at an airport (at a suitable parking posn) or in the cruise at a location (hence you will often see the first few aircraft that approach an airport will be very high as they haven't had the time to descend).As you move through these imaginary squares FS is constantly calculating where aircraft should be (based on their schedule) and placing them in positions in the adjacent squares to you.The idea is that you should never see an AI aircraft simply appear or dissappear (apart from at airports but that's a different thing). It also means aircraft can't get "lost" if their departure or arrival airport doesn't have any parking places (i.e. the "flight" can't taxi to the runway and take off). It also means that aircraft can take off from a distant airport (compared to you) but as they fly past they will be picked up and you will see them.The above may be a simplification but I believe that is basically how it fits together. Overall it fits together very nicely (in my opinion), my only complaints are in the ATC procedures that handle all this traffic.With regards to your question :"Does this also mean that if you have 3000 flightplans FS9 keeps track of all corresponding flights even if they take place on the other side of the earth (in principal a plane could fly from Australia to USA and I could fly from Europe to USA and we could meet there)? Sounds a little bit unrealistic to me."Yes it does, but it won't actually "simulate" (i.e. it won't do aircraft dynamics, draw any graphics, model any interaction with ATC) the aircraft until it falls into one of the nine squares around you. It knows where the aircraft will be at any one time (from the AI schedule) so when you get close you will see it. Sounds unrealistic, I agree, but it has been achieved, hats off to Microsoft eh? :-)Hope this helps,Ian

Hi Ian and Tom,thanks for these informations. What you said, Ian, sounds logical to me. However, wouldn't I then expect that e.g. EDDF has approximately the same number of aircrafts at any time at the gates (ok, might be less in the evening and morning)? Because what I observe is that when I start the simulation almost all of the parking areas are filled but 1 hour later over half of them is empty (because no or only few planes have arrived in the meantime). But maybe this is due to the Lufthansa schedule which of course dominates EDDF. Up to now I always started the simulation around noon.Cheers Alexander Kappes

I think I remember reading about this before in this forum. As I understand it, there are many planes waiting to take off at a given airport simply because you started the sim, in other words a lot of those would have taken off earlier had you entered the sim earlier. It's like they're waiting for you to let them go! I don't remember much more than that but it could be some time, maybe several hours even, before you entered the sim that the planes would have already otherwise taken off. So you will find yourself queuing up behind them unless you can get away quickly, or you might have to wait a while for the backlog to clear. Anyway this seems to be what happens whenever I start off at a busy airport. If I'm wrong, please, someone who knows better put me right!

Charlie, what you say does indeed to be the case....this is explained to a degree in the very comprehensive instructions provided with the brilliant TTools utility that is used for creating AI traffic flightplans.I think that Microsoft have done an amazing job in managing to have the main program track and look after all those AI flights, which although you never see them, they are 'actually' taking place all over the World; aircraft with working TCAS systems show all these flights in progress as you get within aprox 40 miles of them, and you physicaly see them when within 10 miles, it only seems to have that slight hiccup when you enter the sim where all the planes that are around abouts their take-off schedule make a bolt for it!!

Hi Alexander,When you start FS (or indeed change the time) then the AI gets a bit of a kick. Aircraft only start on the ground or in the cruise, therefore those that would be in climbs or descents when "you" start would be missed out. The way this appears to be solved is that those that should be in the descent will be at altitude and in the cruise (hence the first few approaches to an airport after you first start often end up being way too high) and those in the climb are dumped back at the gate (hence when you first start there are loads of aircraft which all suddenly request departure clearance.I understand when you first start FS (or change the time or location) then any aircraft scheduled to leave 15 minutes before that time will be set at the gate and will request immediate clearance for departure (these are the guys who would be in the climb). For somewhere busy like EDDF this could easily fill loads of gates and then choke up the departure runway for the first 30 mins of the sim while all this settles down.When I'm delarting somewhere busy I tend to start the sim early and wait for the rush to die down.Hope this helps,Ian

Thanks for all the detailed answers. Maybe you can answer some more :-)Another observation I made sitting at EDDF and watching the planes take off is that if I change the wind direction to tailwind after some time the active runway isn't changing. Also, at EDDF (default) only one runway is used for landing and take off, though I read that FS9 is capable of using parallel runways. Cheers Alexander

Hi Alexander,Changing the wind direction and the runway not changing is something I've noticed too and I've no idea why. I guess something isn't quite right in the runway selection code.To activate runways for either takeoff or landing then you need to either :a) download AFCAD (2.11 I think is the latest) by Lee Swordy and set one runway to take offs and another to landings.:( download a modified AFCAD for EDDF (for the default scenery I think there are a few) which may already have this modification.Hope this all helps,Ian

Hi,I remember having read (PAI forum? Dunno anymore) that the "wind issue" has already been discussed and it seems to be a "minor" bug. It seems the AI will keep the wind-direction-based runway usage determined on FS startup, regardless if You change the wind direction afterwards.I remember a (FS) flight from EDDF to LEPA, starting on Rwy25L and selecting a good measure (~50kts) of tailwind (from about 10

The "mysteries" of runway selection weirdness by AI and ATC regarding wind direction have, as you say, been noted. While not completely off-topic, it should be noted that users of Radar Contact are waiting for the release (probably in Beta) of version 4 which is planned to note active AI runway use trends when you are within a certain range of destination and control you accordingly for the merge into the approach pattern for the runway in use. Failing the presence of enough AI to determine a trend, RC's normal priority procedure will then dictate the selection.This release is still aways off. Interested parties can search their support forum here at AVSIM.