AI Taxi Direction

[vadriver]

Team

A quick question, at YSSY (and some others) the real world taxi direction / paths for aircraft is essentially via C & B10 to Runway 16L/34R and L&B from.

Is it possible in either the AI program or a program such as ADE to make AI traffic follow that procedure ??

Cheers

John

[Graham Eccleston]

No. AI aircraft will always take the shortest route between the runway and the parking spot.

The same problem exists with the use of runways. Aircraft will allways go to the nearest runway to the parking spot and not the longest or shortest as may be required.

[vadriver]

Graham

Thanks..I suspected as much when I looked at the options in ADE.

& you're right about runway use as well - had an EK A380 ahead of me the other nite for 34R !!

Cheers

[normandean]

Graham's answer is not stictly correct. I developed, togethter with David Butler, a system some years back now that is used in the UK2000 scenery and also by Don Gravestone at Victoria that does force ai traffic to use certain taxiways. It works in most cases, but does have some drawbacks; really its a matter of taste. I call it the "plumbing system".

However, the basic principle is as Graham has said, you just have to fool MSFS into thinking that the shortest distance is the way that you want the aircraft to go!!

Norman

[Graham Eccleston]

Yes, I've 'plumbed' a number of the Orbx airports including Lilydale, Coldstream, Warnervale and Aeropelican but it is a very complex way of setting up the APX and does introduce a lot of new problems.

I think it would be very difficult to plumb YSSY although in reality, it could be done.

[normandean]

Hi Graham,

With some of my larger files I have plumbed just any small area where it is needed. such as GA parking. It works just as well as long as you make the final connection to the taixway system close to your runway entry.

Norman

[vadriver]

norman / graham

thanks for your (enlightening / encouraging) notes ... i think i will accept the challenge @ YSSY, though I think it may be difficult to do it for both runway directions !!

i am assuming one adds a few hidden paths in the APX to achieve the outcome !!

cheers

john

[normandean]

Its a bit more complex than that John. Basically you have a system of taxiways that are arranged much as the plumbing system in a house. The parking spot is the boiler and the runway is the header tank. You can have as many pipes from the boiler to the header tank as you want, and you can have small offshoots from the main system, but the rule is that the pipes from the boiler must never ever join up with those from the header tank.

For the taxi system the lines from the parking spots must always lead to the departure end of the runway, by whatever route you choose, and the routes from the runway must never come from the runway ends, but again you can choose the route.

There are one or two things to watch out for. The first is that you cannot get an aircraft to taxi around three sides of a square if there is an easier alternative. The second is that traffic departing will ghost through arrivals if on the same taxiway, and thirdly, if your final link to the departure point on the runway is on a curve, and aircraft are likely to queue then the last part of the path must be a taxiway link not an apron link.

One other point. When you have traffic moving in both directions at a runway intersection with an HS node then the HS node in the outbound route must not be on top of the one for the inbound, and in the inbound line the next node encountered must be on that same line, not the outbound one.

Now if you have got all that have a go. if you want any help, come back to me.

Norman

[vadriver]

Norman

Thanks again for your notes .. I'm having some success rebuilding / separating paths to & from the runways - and yes there is a clash of departing / arriving aircraft on common taxiways.

One clarification though about your following:

and the routes from the runway must never come from the runway ends, but again you can choose the route.

Do you mean an arriving path should not (preferably) start at the DER for either operating direction (and only be off intermediate taxiway exits if they exist) or that a DER exit is okay provided the arriving path is separated from any clash with a departing path for that operating direction (??)

For now, no rush in this, cheers

John

[normandean]

Hi John,

You cannot use the DER for any arrivals, otherwise the system will not work. In most cases, of course, arriving aircraft will not taxi that far but I know that in some cases it is inevitable. Luckily there is a way around it and that is to make a false exit a little way before the end of the black centre line. Start a taxiway link just short of the runway end from the black centre line and run it parallel to that line to the end of the runway, with separate nodes and a separate node at the end of the runway, just a little shorter than the centre black line. You then make a normal lead off to the exit taxiway. If you expect that ai aircraft may not stop in time to make this exit then you can, in fact, make the exit as I have described and then loop it around the end of the runway, with a triangular path then back to the taxiway exit.

Norman

[vadriver]

Norman

Thanks again for your note .... yes, most AI's @ YSSY for example exit to intermediate taxiways rather than via the DER as you say.

I'm having success with the main taxiway B&C movements so far - though I need to tidy up the lines & lights from the "hidden paths".

Cheers

John

[normandean]

Hi Jim,

Lines and lights are sometimes a real problem with the plumbing system. The best way is to make all the pathways as narrow as possible, I often make mine zero width. You can then use taxiway lines unconnected to the taxiway system in any way to make both centre lines and lights and also edge lines. Again use a line that is as small as you can. The problem then remains that you will see dust and earth flying up when moving over solid taxiways. To overcome this use an apron that will cover the normal taxiway width. This also gives you an advantage, as the apron can be or varying widths more in line with real life than the default AFD structures.

The laying of the taxiway lines should be done after the normal taxiways have been created. The only thing then remaining is to get the HS lines to show. You can do this by widening the inbound or outbound lines at this point to the runway width.

Norman