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Guest R_Driscoll

Taxiing problems - help!

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My newest baby is almost ready to fly but I have run into some problems. My current airport has one main runway, fed by three taxiways, positioned roughly 1/6, 1/2 and 5/6 of the way down the runway. That is, they don't convey the aircraft to the takeoff point. I want to simulate behaviour that the plane "holds" on the taxiway, not near the takeoff point, then when told it can roll to takeoff position, it trundles up the runway, turns around in turning bays at the end, positions itself on the piano keys then waits for final takeoff clearance.I tried running the taxiway all the way back to the turning bays (beautifully represented by Andy by the way!) and moving the two green runway identifiers in to opposite the taxiway entrances, hoping that being close to the runway identifiers would prompt the "hold" dialogue, but it didn't work. Also the landing behaviour of other planes became very strange - planes landing "long" and not using the touchdown zone.Other solutions have failed too. Just running the taxiway along the side of the runway led to massive departure queues (I had AI up to 200%) just inches from large planes hurtling in to land. OHS would have had kittens. Also a lot of planes were waived off - "traffic on the runway", but not all of them.Here's a rough sketch of the problem: | | taxiway | |====================| |=================== runwayx - takeoff point --------->============================================Don't know if this will work with proportional fonts!This might be something Chris, Bogdan, motormouse, Allan, glidernut or Jon might know something about.Or anyone!RobD.

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Rob,Can you do a screenshot in FLED, showing the positions of the taxiway/runway etc? I had a similar issue with Harvey (taxiway too close to the strip) and found out that this 'feature' was preventing planes from waiting on the runway (every time an incoming plane appeared, the AI stops). Once I moved some trees and opened-up the south end of the taxiway, bleedin' AIs queued-up all along the taxiway AND onto the runway.Now, this leads to something... It is quite normal for aircraft to line-up on the runway before receiving final clearance. The number of times it has happened to me is certainly in the majority. The ATC response "taxi to runway 33 and hold means exactly that. I have even sat on Kingsford Smith (sorry, Sydney..) in a Saab 340 charter, being told to 'go ahead' but the pilot wanted to wait for the jet blast from the 747 in front to subside first :-eek The result was a 767 behind had to go around.Moral of the story? Take ATC with a grain of salt, except when they're directing you. After all, they are (experienced and well-trained) carpark attendants with a lot of people to move....and stay away from large fields in smaller aircraft ;):-wave******************* Jonathan Point *******************

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I seem to recall that you have to 'create' a special taxigraph nodefor this.....Chris can you fill in the rest????:-wavePete

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Robert,Yes, I understand perfectly what you mean....but I'm not sure that it is possible in FU3. With respect to Pete's suggestion about "special nodes", I am fairly sure that you are already familiar with these, since they are required at every taxiway exit point along the runway (assuming that ALL of these taxiways are used).What did the departing AI planes do when you extended the taxiways back to the turning bays, and moved the green runway end identifier to a position opposite the taxiway entrance ?The arriving planes are landing "long" because the touchdown point is dictated by the position of the green runway end identifier. You can see this at a default airport in FU3 (San Jose International in the SanFran region....although I have since modified this to allow the AI planes to use the full runway length).I am not quite sure what you mean by "running the taxiway along the side of the runway". Can you explain this ? Where were the "massive departure queues" located ?One final point. How do I increase the AI to 200% ?Chris Low.

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Hi RobD,I carnt help with runways, I hanant got a cloo.But IrfanView is a free program that I use to take snaps insyid Fled or enything on my moniter at the time.After instaling IrfanView, start IrfanView, Options, Capture, remember the hot key,go into Fled, and when your redy, pres the hot key.Its a good little program this, its good for other things too.The latest edition of IrfanView can be downloaded from the Internet at:http://www.irfanview.comorhttp://irfanview.tuwien.ac.at/orhttp://www.ryansimmons.com/users/irfanview/glidernut.:-wave

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Well the links do work, Iv tryed them,I think its the proportional fonts on this thred?You will just have to copy and paste one of them into what ever serch engeinyou are sueing, that will get you to IrfanView, if you whant it.glidernut.

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Yes my fault. Glidernut, do you see the little check box next to message format when you reply to a post? I checked that in the hope that it would make my diagram more readable. But it may have affected your http addresses! Anyway, I can do screen captures.Thanks for all the hints and suggestions. Now I just need to try things out. I have a feeling that the "dotted line" in the "edit airport - lines" option is not just cosmetic, and I will try some things with that tonight.Here is a FLED pic of the problem:http://forums.avsim.net/user_files/64685.jpgTo Chris: the planes queue up right next to the end green runway marker, along the side of the runway (along the taxiway line that I placed there), and then bank backwards along the taxiway as more planes flood in.When I moved the green runway markers in opposite the access taxiways, the planes seemed to ignore the runway and queue up along the side. I don't know enough about the special modes. The end taxiways are connected to the runway directly, but the middle taxiway isn't. How do I connect this? And what are the special nodes? Generally the traffic moves correctly - its only the transition to the runway that is causing headaches.To get an AI of 200%, set the AI to max in FU3 options, then edit the flt3.cfg file - look for the line AI multiplier - my version has a default setting of 0.7. Change this to 2.0. Try it, it will thoroughly test your system resources! Then change it back to normal!Jon, you've described well the problems I've had! I understand that aircraft line up prior to takeoff - its the queues along the side of the runway that are raising the eyebrows of my OHS department. The AI comes to a halt for a short while, but then seems to clear itself by deleting planes that haven't moved for a while - its clever this way.

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Robert,Increasing the AI density to 200% sounds like more trouble than it's worth. Mind you, I will still experiment with this, since lots of AI planes makes FU3 come alive :-)The position at which AI planes hold before given clearance for take-off is unfortunately based on their "taxiway distance" from the green runway end identifier (rather than their physical distance from it). That's why you are seeing queues of AI planes along the side of the runway. They are simply moving along the AI pathways until they approach the AI runway end. I am not sure if this problem can be solved, but if you find a solution.....let me know ASAP !When you refer to "moving the green runway end identifier opposite the taxiway entrance", do you still have an AI taxiway extending up the runway, around the turning bay, and back down to the runway end identifier ? If so, I would assume that the AI planes would taxi along the runway, around the turning bay, and then BACK DOWN THE RUNWAY until they are close to the runway end identifier. Am I correct ? You seem to be saying that they are ignoring the runway altogether, but I am not sure what you mean. Maybe posting some screenshots would be useful ?You say that the middle taxiway isn't connected to the runway. If I am understanding this correctly, it seems that you are not aware of the "special nodes" that need to be positioned along the runway at each taxiway exit.BEFORE YOU FOLLOW THE INSTRUCTIONS BELOW, PLEASE BACK UP YOUR EXISTING COPY OF LUTON AIRPORT !Start FLED, and prepare to edit your new airport. If I am assuming correctly, the green runway end identifiers will still be connected by a blue line.In the EDIT AIRPORT box, select EMPTY NODE from the TAXIGRAPH list.Left click on PLACE, and then left click on the centre node of the blue runway line (make sure you do this precisely). If you have done this correctly, you will see a purple node appear at some point along the blue runway line. This can be dragged ALONG the runway centreline. Move it to a position opposite the middle taxiway exit. You will then need to connect one of your blue taxiway nodes to this "special node". Select TAXIWAY from the TAXIGRAPH list, left click on PLACE, left click on the relevant blue taxiway node, and then left click on the purple "special node". Of course, you can add more blue taxiway nodes between these two as desired (before you make the final connection to the "special node".Your taxiway should now be attached to the runway. This will allow certain AI planes to exit the runway at this point (assuming that they have slowed down in time). When you have completed ALL of your AI work, you need to DELETE the blue runway line. Don't worry, the connection is still there as far as the AI planes are concerned. Just make sure that you have added all of the special nodes that you require BEFORE DELETING THIS LINE. You will not be able to get it back !NOTE: If you position the green runway end identifiers at the ends of the runway, you would need THREE "special nodes", since there are three taxiway exits. After removing the blue runway line, you COULD then attach a piece of taxiway from the runway end identifier to the first taxiway exit (just select TAXIWAY from the TAXIGRAPH list, left click on PLACE, left click on the "special node", and then connect it to the green runway end identifier). This would enable the AI planes to use this piece of runway as a taxiway (which is the reason why you need to delete the central blue line in the first place; the AI planes would assume that THE ENTIRE RUNWAY can be used as a taxiway). If you do this, you would see the AI planes taxi up the runway to the end, and then SPIN AROUND THROUGH 180 DEGREES, before accelerating down the runway and taking off. Unfortunately, I am pretty sure that the AI planes would taxi up the runway towards the end, and then HOLD ON THE RUNWAY ITSELF :-eek. Obviously, that would be extremely dangerous for the little virtual people inside the cabin ! :-)If we could find a way to get the AI planes to hold at the taxiway exit, then that would be fantastic. I have wanted to be able to do this in FU3 for ages, but I do not know the solution (if there is one).Anyway, let me know what happens (or if you understood my rather convoluted instructions above). ;-)Chris Low.

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Excellent - thanks Chris! I always wondered what the empty nodes were for. Your instructions are very clear and I will try that this evening. That solves the middle taxiway, and gives me an alternative method for connecting the other two taxiways. But I will have to rebuild the green runway markers - I have already deleted the connection.Can empty nodes also be used for:1) joins of taxiways - i.e. where taxiway 'alpha' meets taxiway 'bravo' - this often seems to cause confusion in the poor AI controllers' minds!2) runway crossovers, i.e. where a taxiway has to cross a runway.Also, do you have any info on the effect of the dotted lines (hold lines) - I suspect they are more than cosmetic, because I put a hold line on a taxiway (following the airport layout from Andy) and my plane was told to contact takeoff clearance as I got to this line! But it may have been a bug.My main problem over the last week was something different - I wanted aircraft to take one taxiway to the runway, and then a separate taxiway back to the apron after landing. For several days nothing would work - alternative routes, bypass lines, nothing worked. And then when i was repositioning points, I found a gap - the missing link! Fixed, and suddenly all the planes started doing what I wanted. It was delightful - one of those Eureka moments! If all else fails with this lining up on the runway problem, I'm going to move the taxiway onto the grass. Maybe that will scare them into behaving.Cheers,Robert.

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Robert,I'm really glad that I could help. I guess that I just assumed that you knew this, probably because you have already created large airports in the past. Perhaps this would be something that is worth looking at for the likes of Heathrow and Stansted ? They will both have multiple taxiway exit points.You do not require empty nodes for the connection of two differently designayed taxiways. I am not sure what problems you are having, but ATC never has a problem making the distinction in my install of FU3. Mind you, I am sometimes told to "hold short, runway......" after landing by Ground Control, even though I am already on the correct side of the runway ! This isn't a problem though, since the guy generally tells me "cleared to cross runway......" immediately :-)Again, runway crossovers are simply taxiway exit points on both sides of the runway. One "special node" is required here, and you just connect this to taxiway nodes on opposite sides of the runway. So long as the taxiway sections are designated the same on both sides of the runway, ATC will treat it as ONE taxiway. If the runway is active, they will simply tell you to "hold short, runway....." until the coast is clear.Your suggestion regarding the dotted lines is very interesting. I will have to experiment. Have you tried this at Luton ?Yes, I have made the "missing taxiway section" mistake several times. If you ever see the AI planes taking unnecessarily long routes to and from the runway, then it is worth checking your AI connections. It's amazing what can be missed :-)When you say "moving the taxiway onto the grass", you could always just add a section of proper taxiway. At least it would LOOK authentic.Good Luck !Chris Low.

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Thanks Chris - plenty of ideas here to keep me going! I have used the special nodes, with great success for the middle taxiway but with lots of crashes when I tried anywhere else. I couldn't use them to solve the taxiing on runway problem - taxi points tended to unravel and disappear en masse. No matter - I think I've got a reasonable solution now by keeping taxi points sufficiently to one side to avoid wave-off. I haven't tried the dotted lines again - I doubt it does anything and there's only so many things I can test. Your empty nodes has helped enormously, so I'll leave it at that. I can't put taxiways down the side - they ain't there. And if there not there in the original, they ain't there in the model. (Well I'm not really so purist. I invent bits I can't see in photos all the time. But don't tell anyone OK?)Yes, I think I might have to revisit Stansted Gatwick etc. But I didn't do the AI for these airports - they were done for me by Roland Wagener.RobD.

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Hmmm.....numerous crashes are a bit of a puzzle. I haven't had many problems with these "special nodes", although extending the runway to its full length at San Jose International caused a few headaches !Chris Low.

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Hi Rob, Hi Chris,Did have time to read all of this but the nature of getting planes to taxi properly on an airport that isn't the standard one circle arrangement is a mystery to me....Oh I am still working on Filton...if ansgar has a static model of concorde then I will park it in it's correct place!!!I don't get much time these days and progress is slow......Rob(had to post a message as well)

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Rob,Maybe you could send me a few screenshots to illustrate the layout of your airport ? Getting the AI planes to operate efficiently is a problem without full runway length taxiways (which is a problem that the BAA finally seem to be addressing at the real Edinburgh Airport), but I might be able to help if I could see the taxiways that you have built.Chris Low.

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