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Collisions on taxiways

ATC-pie is a radar air traffic control simulation program for the FlightGear multi-player network.

Collisions on taxiways

Postby Darkriser » Tue Jul 04, 2017 3:16 pm

Today I cloned ATC-pie from SF and tried some solo missions.
I was acting as GND controller.
To navigate aircrafts from parking to runways (and vice-versa) I simply click the aircraft and drag to the desired place,
which automatically creates a series of orders (which taxiways to use, when to turn, etc.).
Btw. is there a way to control the taxi path more precisely? To choose exactly which taxiways, turns and aprons to use?

But then I noticed that aircrafts taxiing to parking slots share the same taxiway with aircrafts taxiing the opposite way!!!
ATC-pie simply ignored these collisions as if nothing happened.

Is this behavior intentional or am I doing anything wrong?
Thanks a lot for explanation and much more for coding effort....
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Re: Collisions on taxiways

Postby wkitty42 » Tue Jul 04, 2017 9:43 pm

you can see the AI craft doing this all the time... granted, it could be better but for now, it is what we have...
"You get more air close to the ground," said Angalo. "I read that in a book. You get lots of air low down, and not much when you go up."
"Why not?" said Gurder.
"Dunno. It's frightened of heights, I guess."
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Re: Collisions on taxiways

Postby mickybadia » Wed Jul 05, 2017 9:40 am

Hello,

Darkriser wrote in Tue Jul 04, 2017 3:16 pm:is there a way to control the taxi path more precisely? To choose exactly which taxiways, turns and aprons to use?

The only control besides click&drag is the tick box in the instruction panel to avoid crossing runways when possible (longer but safer). Any ability for finer tuning of the taxi route will require a more complex interface (bad with heavy traffic), whose best spec will obvioulsy depend on airport layout and local rules (bad for a general solution). So the idea for now is to use progressive taxi if the shortest path is not the one you want.

Darkriser wrote in Tue Jul 04, 2017 3:16 pm:But then I noticed that aircrafts taxiing to parking slots share the same taxiway with aircrafts taxiing the opposite way!!! ATC-pie simply ignored these collisions as if nothing happened.

Collisions are not really an issue for ATC-pie. For example, ACFT in the air will happily fly into each other. But I suppose it would make sense on the ground to improve the taxiing behaviour by stopping aircraft that would otherwise be moving too close to traffic in front of them. Up to you to turn them around in case of a dead lock.
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Re: Collisions on taxiways

Postby Darkriser » Thu Jul 06, 2017 9:53 am

mickybadia wrote in Wed Jul 05, 2017 9:40 am:Collisions are not really an issue for ATC-pie. For example, ACFT in the air will happily fly into each other.

Guys, thanks for your answers, but my question was probably incorrectly formulated.
I don't complain about the fact that ACFTs actually happily run into collisions (I'm aware of this),
but the fact that ATC-pie won't raise any warning about the collisions!
If ACFTs in the air break the horizontal/vertical separation, ATC-pie starts yelling at me.
ACFTs on the ground seem to have this warning (intentionally?) turned off.

Btw. I'm aware of the General settings -> Separation, routes, vectors -> Aircraft separation,
but does it mean that ATC-pie absolutely ignores separation below this altitude?
When controlling ACFTs below this altitude am I left on my own to manually watch and keep the separation?

(don't get me wrong - this is NOT a complain, just a polite question)
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Re: Collisions on taxiways

Postby mickybadia » Thu Jul 06, 2017 1:34 pm

Darkriser wrote in Thu Jul 06, 2017 9:53 am:If ACFTs in the air break the horizontal/vertical separation, ATC-pie starts yelling at me.
ACFTs on the ground seem to have this warning (intentionally?) turned off.

There are two kinds of alerts: (1) measured separation loss, and (2) anticipated route/course conflicts based on registered assignments (strip routes & vectors).
...and one could say, two types of traffic: airborne and ground. Alerts indeed only apply to airborne traffic.

Separation loss makes little sense on the ground, since it is mostly the pilots' responsibility: "follow ...", "taxi via ... behind ..." are sufficient instructions. Also distance cues for dangerous movements are too small and depend on the planes' sizes.
One could picture taxi route conflicts, but it seems only barely realistic in the general case (controllers do not register taxi clearances on progress strips like they do in-flight routing). Also, impossible with the scarcely available ground route data and no way of registering precise taxi instructions.

But this is where I say it makes sense for AI (simulated) traffic to stop if there is traffic ahead. That behaviour is rather realistic, and keeps you from getting away with bad ground management since you will have to intervene in the case of opposite routes. Otherwise traffic locks in place, which is better than just alerting. Thanks to your remark, I have already implemented something now being tested for the next upgrade. ;-)

NB: To control a complex ground layout, I recommend using a loose strip bay with the ground chart in the background, and moving strips directly to reflect the assigned routes.

Darkriser wrote in Thu Jul 06, 2017 9:53 am:Btw. I'm aware of the General settings -> Separation, routes, vectors -> Aircraft separation,
but does it mean that ATC-pie absolutely ignores separation below this altitude?
When controlling ACFTs below this altitude am I left on my own to manually watch and keep the separation?

Yes, you choose a floor for conflict checks, under which you decide an en-route type of separation becomes unnecessary. Nobody wants a 5-mile sep on traffic at airport circuit level.
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Re: Collisions on taxiways

Postby Darkriser » Thu Jul 06, 2017 2:32 pm

I love this community...
Many thanks for the detailed answer!
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Re: Collisions on taxiways

Postby mickybadia » Mon Aug 07, 2017 1:48 pm

Hi there, the new v1.3.4 uploaded yesterday includes the AI taxi stop behaviour we have been talking about here...
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Re: Collisions on taxiways

Postby Darkriser » Mon Aug 07, 2017 4:37 pm

I wasn't even aware you are working on this!
What a surprise...many thanks for the effort....
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