FSX ADE 1.45.6 - Fault Finder

[Andrew]

I am helping a friend of mine with an airport. His issue was the AI plane stopped on the runway right after exiting the taxiway, and it would not take off.

A closer look revealed the Hold Short Node ring overlapped the Start position. So I moved the Hold Short a little back, so that a little bit of the red ring overlapped the runway edge, and made shure it did not overlap the Start. This solved the problem, but I am not shure the overlapping was the issue, or it was caused by the Hold Short too close to the runway centerline.

Fault Finder did not detect this. Is it possible to make it detect such issues?

Cheers,

 

[jvile]

I am helping a friend of mine with an airport. His issue was the AI plane stopped on the runway right after exiting the taxiway, and it would not take off.

A closer look revealed the Hold Short Node ring overlapped the Start position. So I moved the Hold Short a little back, so that a little bit of the red ring overlapped the runway edge, and made shure it did not overlap the Start. This solved the problem, but I am not shure the overlapping was the issue, or it was caused by the Hold Short too close to the runway centerline.

Fault Finder did not detect this. Is it possible to make it detect such issues?

Cheers,

Andrew

This problem may be a first. In all testing I don't know if anyone has ever tried to find out if the holdshort is to close to the side of a runway the AI Plane will not advance onto the runway.

I will do some additional testing based on what you see.

Is the airport you are working with a stock FS airport?

 

[Andrew]

Hi Jim,

I am posting a pic of the issue before I dragged the Hold Short back. I forgot to mention the taxiways at this point were 0 meters wide - that might be a part of the problem. But Fault Finder should have detected anyway. I have told my friend to make the width at least 2 meters as I remember there was something with taxiway minimum width and the width of the nose wheel on the AI planes.

Btw, it is not a stock airport. What you see on the pic is supposed to be hidden by a gmax polygon. The reason for all the rwy concrete is to avoid dust coming from the planes wheels.

Cheers,

 

[jvile]

Hi Jim,

I am posting a pic of the issue before I dragged the Hold Short back. I forgot to mention the taxiways at this point were 0 meters wide - that might be a part of the problem. But Fault Finder should have detected anyway. I have told my friend to make the width at least 2 meters as I remember there was something with taxiway minimum width and the width of the nose wheel on the AI planes.

Btw, it is not a stock airport. What you see on the pic is supposed to be hidden by a gmax polygon. The reason for all the rwy concrete is to avoid dust coming from the planes wheels.

Cheers,

First issue

You have almost a 90 degree angle in the holdshort link and the taxiway that connects to the runway. FS does not play well when angles are in hold short taxiway links in that manner. We set a radius circle around the holdshort node for a reference but this distance is for only one type taxiway to runway connection.

This picture shows the radius distance and the type taxiway connection the circle is designed for. Most scenery designers are of the impression that the radius circle is the max distance to the side runway texture as illustrated. That is only true for ths type taxiway to runway entrance.



Now we look at angled taxiways to runway that have holdshorts. FS uses a formula for distance based on the taxiway angle. This picture shows that the runway entrance taxiway to runway displaced threshold is over 600 ft and the radius circle is no where near the side runway texture.



The distance formula says if we angle a taxiway to a runway the holdshort can be pushed back much further and FS still honors the holdshort node properly. In the above picture a plane will hold so it is not in the way of arrivals and then ATC will clear the plane the total 600 ft which then the plane takesoff (changes states in the Explorer .dll ToolBox)

Since you have 2 angles in your picture I cannot be sure what the behavior will do when the code is passed through the distance formula.

The 2nd issue is the 0 ft taxiway width.

I know a lot of designers use 0 ft taxiway width but FS gets confused if the 0 ft taxiway width is at the hold short node. This is because ATC does not know where the AI Plane is located (looses focus) and the AI Plane will get stuck under certain conditions. The other problem that surfaces since ATC does not know where the plane is, other planes do not know where each other are. A 0 ft taxiway width at the holdshort causes additional AI Planes to run into each other while holding in line for takeoff clearence from the Tower.

The AI_Player and ATC .dll uses the main gear contact point footprint to know where a plane is located on certain parts of a runway/taxiway network. If the planes main gear is not touching the width of these areas of the network you get into problems with ATC and taxing aircraft.

 

[Andrew]

Thanks a lot for the heads-up, Jim.

I have straightened out the angles. Seems to me now that there is no problem with a Hold Short overlapping a Start as long as we follow the basic rules discussed here.

Regarding issue 2, I remember there was a thing with taxiway width related to ATC. In my own projects I use width at least 2 meters for backtrack turns (found out by trial & error), and 3 meters where huge planes like B747 and AN-124 go. Those are planes that can be seen often, even in little Norway

Cheers,