I'll try and keep this simple. (first attempts on all of the following) I've just built a small airport using Afcad, Fs Flatten, and Exbuilder. I then thought It would be nice to put some Ai movment on it. I used YRoute to make a simple first attempt at Ai traffic which involved the default Ai Dash 8-100 taxing from it's parking space to the runway, taking off, doing a circuit of the airfield and landing again then going back to it's parking spot. Now it taxis and goes down the runway at ground level then takes off but on landing it goes down the runway and taxiway about two or three feet off the ground. I tried the same flightplan at another default airport and there wasn't a problem, took off and landed at ground level. I can only assume I've not set something right in my build. I've tried adjusting the airport height in Afcad and also in the Airport Text File decompiled with TTools with no beneficial affect. Any help please. Jerry.

This indicates that you have changed the airport elevation from the default.If so, try placing a copy of your Afcad in ...FS9SceneryWorldscenery.If you use ADE9 it will do this automatically.If this is a new airport then verify that your airport and your flatten are the same elevation.regards,Joe

Thanks for your reply Joe. Yes it's a new Airport and during construction Flatten and Afcad was set to 40 feet, converted to meters in flatten. Increasing the hieght in Afcad makes matters worse so everything is set to 40 feet as far as I can see, except for the airport text file decompiled by TTools which shows 39 as the last entry in my airport details. I tried altering that as well but makes no difference as far as I can see. I moved the Afcad file to the World/Scenery folder but no change either. I must say though, the distance has dropped to about one foot now? Can't be far off. Thanks again, Jerry.

FYI, the airport altitude in TTools is for planning use only and will not have any affect on AI performance if it's a few feet off.regards,Joe

Thanks for your reply Joe. Yes it's a new Airport and during construction Flatten and Afcad was set to 40 feet, converted to meters in flatten. Increasing the hieght in Afcad makes matters worse so everything is set to 40 feet as far as I can see, except for the airport text file decompiled by TTools which shows 39 as the last entry in my airport details. I tried altering that as well but makes no difference as far as I can see. I moved the Afcad file to the World/Scenery folder but no change either. I must say though, the distance has dropped to about one foot now? Can't be far off. Thanks again, Jerry.

To be clear, Joe said to place a copy of the file, not to move it. If you change the elevation of an airport, you need:

1. Your revised A&FD file at a higher level than the default A&F Data
2. A copy of that file (or certain critical data therefrom) at a lower level than the default A&F Data. The reason for this is that a "bug" in FS causes it to adopt the airport altitude shown in the first file loaded for AI traffic.

This file may be useful:http://library.avsim...nson&CatID=rootJohn

Are the runway elevations set the same as the airport elevations in afcad.?

To be clear, Joe said to place a copy of the file, not to move it. If you change the elevation of an airport, you need:

1. Your revised A&FD file at a higher level than the default A&F Data
2. A copy of that file (or certain critical data therefrom) at a lower level than the default A&F Data. The reason for this is that a "bug" in FS causes it to adopt the airport altitude shown in the first file loaded for AI traffic.

This file may be useful:http://library.avsim...nson&CatID=rootJohn

Hi JohnI took a look at your file and have to say I am somewhat surprized and confused. In FS2004/FSX MSN (ACES) does not consider a Airport Altitude problem a "bug".MSN does not want us to edit their elevation in the stock AP, FL and HL bgl's so they give us the ability to create what we call a pre-load airport bgl. This pre-load bgl is nothing more then a AFD Header where we can change the Stock Airport ICAO, Name or Airport Altitude. This was documented in a post by a ACES developer during the beta of FSX which says

FlyingsCoolWhile we are on this topic, there is a subject that is near and dear to my heart. Will we be able to exclude existing flattens? Will we be able to easily change the altitude of an airport?As you know, currently, you have to preload FS with a basic AFCAD header with the new altitude data loaded before the default airport, and then use a second AFCAD to lay out the redesigned airport. To remove existing flattens, you currently have to edit the default code. A big no-no.Thanks,Thomas

In this file, scfafd1a.zip you state the following in the readme

I have to thank Stuart Gilmour for drawing my attention to this method, which appears tohave been originally conceived through discussion between Gary Summons (of UK2000Scenery) and Lee Swordy (the writer of the AFCAD software). I'm not looking for a pat onthe back - the credit goes to these people. This document simply sets out the background tothe problem and how to fix it.

I for one always like to see credit given when credit is due but in this case the background to the problem and the pre-load bgl has nothing to do with any of these people.The following post explains what payware airport had the wheels sunk in the ground when FS2004 was released and a paper that will be published on the FS altitude coding.http://forum.simflig...h__1#entry82238The following post explains how Peter was able to use duplicate AFCADs. The technique was further developed so only the AFCAD header needed to be compiled.http://forum.simflig...h__1#entry82433Since FS only reads Altitude (elevation) prior to AFRICA in the Title=Default Terrain and Title=Default Scenery for the Static AI Planes sitting on the ramp it becomes more clear why FS places by default all the AI Traffic bgl's into the Scenery\World\scenery folder. jim

Are the runway elevations set the same as the airport elevations in afcad.?

Hi Stan57The Airport elevations as seen in the AFCAD property window does nothing. All Altitudes are read from what we call the fallback method to the AP9 / APX bgl. In the case of a flatten then the Airport altitude must also fall all the way back to the SceneryWorldscenery folder as a preload bgl.When you look into AFCAD ALL elevations must agree with the ARP elevation if no flatten exist. If a flatten does exist all AFCAD elevations must agree with the Flatten and a pre-load Airport elevation bgl be placed in the SceneryWorldscenery folder. jim

I took a look at your file and have to say I am somewhat surprized and confused. In FS2004/FSX MSN (ACES) does not consider a Airport Altitude problem a "bug".MSN does not want us to edit their elevation in the stock AP, FL and HL bgl's so they give us the ability to create what we call a pre-load airport bgl. This pre-load bgl is nothing more then a AFD Header where we can change the Stock Airport ICAO, Name or Airport Altitude. This was documented in a post by a ACES developer during the beta of FSX which says

Well perhaps we'll have to agree to differ on this but FS9, like other versions of FS, is supposedly designed to be completely extensible and by adding an A&F data file you can easily change the elevation of an airport all bar two things:

1. AI traffic continues to respect the original airport's altitude.
2. Runways do not respect the new airport elevation without some sort of flatten when taxiways and aprons do (outside the scope of this discussion)

I choose to call these "bugs". The development team may well choose to say they meant to make it that way and therefore it isn't a "bug" but a "feature". Either way I can see no good reason to do so and I do not think things were planned that way.The file/guide I published in 2003 (a while before those comments were made concerning FSX in Beta, I imagine) was based on knowledge then available and whilst it is easy to say this many years on that there are different ways to achieve the desired effect the principle still stands and works well."Pre load airport BGLs" had not even been conceived in those days and the simple placing of a copy of the full A&F file did and does just the same because it contains the necessary data to achieve the desired result. Either method works equally well.John

Hi,Back to the original poster. Is this a brand new airport, or are you modifying a stock airport? If a new airport, is there another stock airport nearby?

Whenever i have this sort of problem i use the program "Jabbgl" first to get the AI aircraft on the ground and then alter the afcad to match the elevation.I guess this is what you just said Jim.

Whenever i have this sort of problem i use the program "Jabbgl" first to get the AI aircraft on the ground and then alter the afcad to match the elevation.I guess this is what you just said Jim.

I once did a bit of testing of Jabbgl, and my result was that it works correctly only if the airport is at or above sea level. It's fine for fixing your own system, but publishing Jabbgl-modified AP9 files is probably not the best idea. But I thought the OP stated that was a "new" airport (not a mod of an existing FS9 one), so all this discussion isn't helping him much.scott s..

But I thought the OP stated that was a "new" airport (not a mod of an existing FS9 one), so all this discussion isn't helping him much.

You are absolutely right, Scott - and I apologise for getting "blown off course" here.From the original post "it taxis and goes down the runway at ground level then takes off but on landing it goes down the runway and taxiway about two or three feet off the ground" This isn't something I have ever seen and I really can't think why behaviour on landing should be any different to taking off.Reference Stan57's comments on identifying real altitude, if you don't have the utility he mentions another simple way to do this is to load the default DC-3 and subtract 9.9 feet from the figure given when you press Shift-Z a couple of times.Best wishes,John

Hi All, sorry for taking sooooo long to reply to your replies but work got in the way of any further tinkering with my new build airport. One thing I forgot to mention and I'd forgot I had it installed was FSGlobal. After I uninstalled it and reset my ground level in Afcad and FSTflatten I no longer have this problem. All Ai take off on the runway and land and taxi at ground level. Problem solved? well yes and no, I've now lost FSGlobal and improved terrain which isn't a problem for my new airport location as I've built in on my home town and East Anglia isn't noted for it's mountain ranges or hills for that matter but even when FSGlobal was installed if an Ai took off from my airport and landed next door at RAF Lakenheath (Modified-not by me) or any stock/modified airport it landed on the runway at ground level. But for now I shall continue to build up my airport. Many, many thanks for your time and replies.PS. Where can I find this ADE9 program?

Hi,Your flatten and AFCAD files must be in a scenery layer higher in the Scenery Library listing than the FSGlobal layer for this to work. Were they?