1 - Background:

Each new version of Microsoft Flight Simulator has seen an increase in the complexity of visual scenery and complex 3-dimentional 'ground' scenery was introduced in FS2000. Other advances include moving objects (such as ships and road vehicles) and interactive aircraft flying around you in the skies and taxying on the ground.

Therefore, it is not surprising that some scenery files will only work in some versions of FlightSim and not others. Sometimes they will work, but with a limited function. There is no hard and fast rule about what will work where, so it is important to read the help files that come with downloaded scenery to find out how to use it. Sometimes you just have to try it out and see.

The scenery in Flight Simulator is organized into areas and layers. To display the proper level of detail as you fly throughout the Flight Simulator world, it's important that your scenery be organized into the correct areas and layers.

The scenery in Flight Simulator includes the following areas:

• Global - this area includes only basic ground and water textures for the Flight Simulator world. Global scenery has the lowest priority think of it as the basic earth, sea, and sky textures of a landscape painting. You can have only one global area active at any time.
• Regional - regional scenery areas include more information, such as runways and navigation aids (VORs and NDBs). Regional scenery does not contain buildings and other structures. Think of regional scenery as filling in general outlines of a landscape.
• Local - local scenery includes the highest level of detail, including buildings and other objects. Local scenery completes the landscape.

If you install new scenery, you must know whether it is global, regional, or local scenery. Most add-on scenery should be assigned to the local level because it typically includes detailed information about specific areas.

Each scenery area is associated with a layer, or priority. Layer 1 has the highest priority. Think of it as the top of the scenery "stack." The specific layer number assigned to an area isn't as important as that area's relative position in the stack. The global area should always have the highest layer number, which puts it at the bottom. All regional areas should have layer numbers less than the global area's layer number, and all local areas should be higher in the stack than the regions they're associated with. For example, if the Europe region is at layer 25, an added airport (a local area) in London should have a layer number no greater than 24.

2 - Downloading & Un-Ziping files:

When you download scenery it will most probably be in a compressed format called a 'Zip' file and will have the extension '.ZIP' at the end of the filename. This is a standard format used across the internet which conveniently groups files together into one and reduces the total size to improve download times.

The download is initiated by clicking on the link to the scenery file and you will be asked into which directory you want to save the file on your computer's hard-disk. Depending on the size of the file and the speed of your internet connection downloading may take anything from a few seconds to hours.

When the download is complete, you will need to uncompress the Zip file to access the vital files inside. For this you will need a program such as WinZip or PKZip. If either of these programmes is installed you can click on the downloaded file and the program will run, displaying the enclosed files. If you are using WinZip click the 'Extract' button to specify which directory to extract the files to.

IMPORTANT: ensure you have selected both the 'All files' and the 'Use folder names' options.

Finally, click the 'Extract' button to unpack the files.

3 - What the Files do:

Scenery areas are made up of two types of files: 'BGL' files and texture files. BGL's contain the data that is used to draw the scenery in the FlightSim, and texture files, as the name implies, cover the scenery with textures.

A scenery area may have just one BGL file, or many (the Europe scenery that comes with FS98 contains 425 files). There are no other file types that 'draw' scenery. All BGL files have the extension '.BGL':

  e.g. example.BGL

Texture files may come with any extension. Here are some of the most common:

  .TXR         - standard FS texture.
  .R8          - standard FS texture.
  .0AF - .9AF  - standard FS texture (aircraft textures, but may appear in scenery).
  .OAV         - Airport (the freeware program) texture files.
  .PAT         - Visual Object Designer texture files.
  .HAZ         - standard FS texture.
  .PAL         - standard FS texture.

There is only one format for scenery in all versions of FlightSim.

4 - Scenery Conflicts:

Conflicts will occur when the geographical locations of two scenery files overlap. For example, if you install scenery for an airport that is already depicted in the FlightSim, you will have two airports, either overlapping each other or displaced by a short distance. Taking off from a runway which has a terminal building in the center can be a little disconcerting.

To avoid conflicts you must 'turn off' the scenery that you dont want. This is perhaps the hardest part of scenery installation since sometimes it involves turning off the scenery for a whole region. An example of this is the Gatwick scenery that you can download from these pages. Microsoft made their scenery in such a way that to 'turn off' their version of Gatwick you must deactivate the whole 'Europe' scenery area!

However, many add-on scenery areas have been designed to 'cover' the existing scenery, so you often don't have this problem. This is because many scenery areas have been designed to compliment existing scenery, such as adding static aircraft to the standard FlightSim airports. Of course, this is not even an issue if you are adding to where there is currently no scenery anyway.

Remember, read the text files which come with the scenery. Given the nature of the program, each scenery area probably has a slightly unique feature which requires you to do something to your scenery setup that you were not expecting! The text files will (hopefully) explain all.

7 - Tips:

1. Create a directory to store downloaded files, and another to un-zip them into. On my computer I have set up one called:

     C:\Arrivals\Unzip

   (All downloaded files are saved to the 'Arrivals' directory, and are unZiped to the 'Unzip' sub-directory)
    
2. Read the designers' 'Readme' files! They should contain all the information you need to install the scenery, and may suggest how to change or improve them to your specification.