I've already asked this over in the PAI forum, but even the very competent people there could not help me out.Symptom: Whenever I switch on AI and I have more than, say, 50 flights in my various flightplans, FS crashes. It runs fine as long as I only have a few flightplans installed. This is most bizarre, as my AI worked great until I did a major overhaul (re-naming some planes, downloading and installing summer 2006 plans). I previously had several tens of thousands of flights, and never any problem having traffic at 100%, ASV weather, and flying my PMDG 744 into a big add-on airport like Aerosoft Frankfurt or Cloud 9 Los Angeles.So what could the reason for my crashes be? And how can I fix it?Here's what I already checked:- PC power: 1,024 MB RAM, 2GHz processor, 256 MB graphic card; Windows sits on drive C, which still has about 16% of free space left; FS sits on drive D, which has about 40% of space left; both de-fragmented- FS: I did a complete re-install, so what I am witnessing is happening on a clean install of FS. - Installed add-ons: none. Just FSUIPC, some AFCADs, my AI planes, and my flightplans - I checked for double AFCADs: no problems - I used ACA Aircraft Analyser to check for errors in my AI planes: found some and repaired all "double entries", "missing sim", "missing model", "missing air file". Still have some errors with some of them, such as "potentially missing lightmaps" and "callsign not existing". But I think those cannot affect AI performance. Also, I have used one application that hides all my AI aircraft from the aircraft menu in FS.- I used AITM to check my flightplans: corrected all the "timing" errors. So what could the error be? Something in my planes? Something in my scenery? Some error in compiling the traffic.bgls? Too many traffic bgls? Something in the aircraft.cfg (the only thing I did not de-install)? Some corrupted file (I would doubt that since I completely re-installed FS)? Something with the AI engine or the ATC engine? What would I need to look for? I am absolutely devastated because I cannot fix this problem since three weeks. I am quite experienced with FS, but this is the first time I am completely lost in 8 years of simming. Any hint would be useful!Thanks

Check for a corrupted AI aircraft texture. I had this problem a year or so ago, very frustrating and can be difficult to track down. I would start by adding your traffic bgl files one by one with 100% traffic until you get to one that causes your FS9 to crash. Of course, if you use one giant BGL file for all your traffic, things will be much more difficult.

... I am doing that, but in a different way: I made all planes visible in FS, and now go through them one to one to check whether FS is crashing. I believe I found one, which is one of the textures (or something else) with the Aardvark ERJ-170. BUT: there is ERJ-170 going into some of the airports where I crashed FS (KSFO, ELLX). Would it be enough for that plane to pass through that area, even if not visible from my own plane, to crash FS? Or would the crash only occur if the plane is actually going to display its textures in my FS "window"?Thanks for any explanation!Chris