Runway exits in scenarios (r18)

[Michael Pike]

I've been experimenting with r18 runway exit selection. It's a very useful facility but the behaviour of aircraft seems a bit unpredictable. The main change in the login seems to be that aircraft will back track and return to the nearest point on the exit route if they miss the turning. The problem is I can't figure out how to select the right exit - the planes often decelerate very gradually and miss the turning when they ought to have made it easily Several planes have even gone off the end of the runway and then back tracked - their speed on the runway seemed to be coming down nicely - no reason to overshoot as far as I can see. The same scenario in previous versions did not exhibit this problem.

 

My question is, does anyone have any insight into whether the design of the runway exits can influence this? Is the taxi speed specified for the exit relevant? Should the exit start from the centreline or from the edge, or somewhere else? Is there a standard speed that aircraft need to reach before they will start to turn off?

 

If I use the old vacate left/right option before landing, the behaviour is even more erratic. Planes still back track instead of going on to the next exit.

 

I'd like to be able to use this version for training because it solves a lot of the problems with earlier versions, but it is sometimes a bit difficult to comply with an aerodrome controller's instructions!

[Michael Pike]

After further experimenting, I have got rid of many of the anomalies by redesigning the exits. It seems the algorithm for the planes to exit is to head for the nearest point on the selected exit not the start coordinate. On major airports with rapid exit turnoffs, I'm sure this works well but the regional airport I'm working on doesn't have those. Some of the exits curve right back to face the landing direction. The end of the exit (beyond the stop bar) is therefore nearer to the landing threshold than the start of the exit, if you follow me. Everything behaved as expected once I extended the start of the defined exit right down the runway centreline until it was closer to the threshold than the end point.

 

Just posting this up in case it's helpful in other situations like this.