I've replaced all the default aircraft with commercial aircraft and now occasionally I come across an airport with a couple of aircraft stuck in a loop.Is this because I substituted too large an aircraft for the original default? Like, I replaced the "Caravan" slot with an A319. Is that why they're circling? They can't fit in the gate assigned to the flight plan? By the way, I haven't changed the original default flight plans, just the planes that fly them.They taxi ride around and around and "morph" through the terminal or other parked aircraft.I'm going to try substituing craft more similar in size. Like a Saab 340 for a Caravan to see if that makes a difference.Am I barking up the wrong tree here?Dave

I'm no expert, but it sounds like an AFCAD problem to me. Bigger planes are a bit less maneuverable and when two nodes, or a node and a gate, are really close together, particularly if the turn is tight, a big plane will turn to try to hit the node and start circling around it. If you see an AI plane circling, that's usually the problem, in my experience.Solution: open the AFCAD file for the offending airport and space out the nodes that are causing problems. When possible, also decrease the angle of turns, especially near gates. Reducing AI traffic speed on turns (if you've previously increased it) might also help. Lots of people put it up too high, especially on tight turns, and this can cause problems like those you mentioned.Hope this helps.Marc

Are you using PAI aircraft? PAI's 763 behaves as you describe.