Floating Airports

[Vulcan 14]

I hope someoe here can explain why I have a strange problem with some add-on freeware scenery and also offer a solution.I am not going to name the scenery of the author as apart from this problem the scenery is fine.The scenery is an airport and looking in spot view I would guess that the add-on is mainly the parking apron and buildings with the runway being the default FS9 scenery.I installed the scenery, positioned there and slewed around to check it out, everything was normal and looked fine.A couple of days later I made a flight to this airport and as I taxied onto the apron noticed that the terminal buildings had vanished.In slew mode and spot view a large crater had appeared where the terminal building was so only the roof was showing at apron level.AFAIK I had not changed anything in FS9 but to be sure I fired FS9 up again and positioned at the airport and sure enough the buildings were in the crater.I contacted the author who sent me some more BGLs which he hoped would fix the problem.Installed the new files, positioned at the airport and the buildings were normal again.Did another flight to the airport and this time found the buildings were floating in mid air!TIA

[Guest GCBarni]

Elevation conflict. Perhaps an Afcad file or other nearby scenery, including terrain mesh addition can be the culprit.

[Vulcan 14]

Just disabled all my add-on mesh files and the problem persists.I have just been doing some more tests which may or may not be of help.The airport is on an island which is only about 14nm by 8nm. If you slew to about 22nm or more away from the airport and then come back in the building 'float', if you stay within 20nm they do not 'float'.The elevation of the apron is 304ft. If I slew over the buildings I cannot descend below 304ft regardless of whether the buildings are 'floating' or are sunk into the crater.If I end the flight after the buildings are floating and then select the same airport the buildings remain floating. However if I select another airport from 'create a flight' and position there then select the problem airport from 'create a flight' the buildings are back on the ground and no longer floating.Is that of any help?TIA

[Guest GCBarni]

It still looks like an elevation conflict. We'd need to know the island specs: location, elevation, etc. Is this an island you designed, or is it default? If default, are you adding the airport to it? If you're adding the airport, which program do you use?The distances you quote confirm, more or less, the proper action for FS; that is, as you approach, the info is being generated and as you go further away, that info is dumped.It also looks like the 304 feet is the "hardened" elevation but the buildings, and maybe the Afcad info(if such exists) are in conflict. When you measure this 304 foot value, which aircraft are you in and are you allowing for the landing gear height? For example, for a default Cessna you subtract 3 feet from the displayed altitude.

[Vulcan 14]

GCB,Thanks for the reply and I think I am now out of my depth , and will leave it for the scenery designeer to persue.The island is a default island, from what I can tell only the airport buildings and apron are part of the add-on, but notice that the apron is always in the correct place only the buildings move vertically.There is no AFCAD file with the scenery.The 304ft is shown by FS9 in spot view and is the altitude shown when the default Cessna is parked. The other altitudes I mentioned are when the Cessna's wheels are in contact with what should be ground level of the buildings.I have heard back from the designer who says he does not know why this is happening but he is working on another version which hopefully will not have the problem.I did mention I had posted here so he may just drop in and seek advice.Thanks for your interest but for now I will leave it with the scenery designer and keep my fingers crossed for the next version.