Im currently engaged in investigating a problem where I get a CTDwhen flying between KGCN (Grand Canyon) and KBCE (Bryce Canyon.). About 90 miles south of BCE northbound, the sim does the CTD...snap...gone...back to desktop. The problem also occurs southbound just north of the canyon. Does not seem to matter what airplane Im in. I use Georender KBCE (Georender 6) but thislocation is well south of that scenery and shouldnt be a factor.KGCN is default without even an afcad modification.Im flying over default scenery as far as I know. Anybody got any ideas? Last flight I was southbound and picked up an entrance tothe canyon from the north and at about 10500 ft...zap.Is this a known issue at all? Its repeatable on my system as I've had it happen in the same location on 3 different flights. Would suck to not be able to fly in the grand canyon!eric

When you say you're flying over default scenery, does thst also mean you haven't applied any AFCAD, Mesh or Landclass updates? Repeatable CTD's seem to be related to two things--AFCAD/Scenery updates, and the "seasonal" texture issue.I fly over the Grand Canyon quite often--KPHX to KSLC is one of my favorite flights, especially around dusk. I've never had a CTD on that route in either direction.-John

John, I have no afcad files in play for any airport in that vacinity. KGCN is nearby, but is default. I do use the Fsgenesis landclass, so I guess Im not "default" per se, but I have never had any problems with it anywhere else. But it is pretty extreme scenery around the canyon. Just verified using afcad that the only afcad file I have is the stock one. Sooo...no idea.Let me see if i have a problem flying east to west.... I do have it going north/south etc.ERic

"I use Georender KBCE (Georender 6) but thislocation is well south of that scenery and shouldnt be a factor."Keep in mind that any add-on may manifest itself in a CTD some distance away from the actual point where the add-on is supposed to update...

This also happens to me when I fly near Boise, ID.Ron

Hi all."Keep in mind that any add-on may manifest itself in a CTD some distance away from the actual point where the add-on is supposed to update..."I just bolded it because not paying attention to this is the biggest stumbling block to getting rid if CTDs ( non-seasonal type ). John is 100% on target here! An AFCAD with an error many kilometers away may still cause a crash. The AFCAD program has an error detection process, but this can still miss the error... ( sometimes a start position misplaced or duplicated ).Another cause of CTDs of this type are textures that are not allowed in the sim ( usually 8-bit unmipped ).Your Scenery Library should be organised in a manner that will allow you to quickly isolate bad BGLs. That means adding scenery with new project folders that are added to the Library, instead of dumping addon BGLs into the default folders. This way, problems are isolated by deactivating the scenery addon through the Library.Dick

Also try the same route but in a different season, ie, Fall for instance to ee if it might be a "seasonal CTD".

Dick,"Another cause of CTDs of this type are textures that are not allowed in the sim ( usually 8-bit unmipped )."A few of the defaults are like this, such as the 001b2m(11-15), 001f2m(11-15), 900b2m(11-17), 901b2m(11-15), and 901b2m(11-71) series .bmps? Should these be reformatted to include mips?Another question on the texture formats, most ground textures are dxt1 with mips, I've found a few that are non dxt1, such as the 025b2sp(spring) series and yet the other 025b2 seasons are dxt1. Kurt M

My addon scenery is all kept out of the FS9 directories and separately into a FSScenery directory, then added individually to the sims scenery.cfg file. I never overwrite anything...always backed up. Only thing that ever goes in the addon scenery folder is afcad files. All this is very helpful, but cruising over a region I almost NEVER fly over, in the middle of the southern Utah desert...I get a CTD.Will keep testing with all these good ideas in mind. Trying to pinpoint the exact lat/lon now so that I can narrow down the list of likely suspects.Since we are on the topic of bad afcads...I wonder what the range is on one of those...when does the sim recognize it (how far out?) Im sure an afcad for KBOS wont bother my flight in Georgia (would it?)Eric

I reformatted 29 .bmps (001b2m,001f2m,900b2m,901b2m,902b2m series) with Imagetool. First I formatted them as a mask and then added mips. I had previously copied some of these (001b2m and 001f2m series) to a temp folder because I had wondered about the formatting and wondered if it could have anything to do with the seasonal CTDs. I had forgotten about them until I saw this thread.I checked at LFNC during winter where I had previously gotten a repeatable CTD and no longer seem to have that problem. I'll have to to some more checking tomorrow if I have the time.Kurt M

Afcad is responsible for information garnered by the GPS guage so, concievably I suppose, if the guage were set to the maximum range of 500 miles and you were at high enough altitude, an Afcad could affect a pretty large area. The same might apply to the MAP View, since it too ultimately derives the information from the Afcad file.Flattening switches can have far-reaching and surprising affects. One example stands out from an acquaintance who made an error of merely one digit. The area he was dealing with was supposed to be affecting Western Canada somewhere, but the mistake caused a ridge extending from Central Quebec, all the way across the Atlantic to Great Britain!

Hi Kurt.I don't believe those bitmaps should be mipped. They are not terrain bitmaps, but masks for the landclass tile blending. I dont know if there is any harm ( or good ) in converting them to 8-bit mipped.The spring texture you found was probably overlooked by MS when they made their DXT1 images, but it should cause no harm. The default textures do not cause crashes.Dick