I would like to break down each section (legtype) we add so you can understand what each entry (attribute) is being used for.
We have our ILS (LOC + GS + DME) on the ADE GRID for RWY19R. I previously stated and it should now be understood that the ILS is owned by the runway in FSX. That means it only serves one purpose. The purpose is so a User Planes radio can recieve the ILS signals and then see the LOC, GS and DME on the aircraft panel.
The first thing we want to do is add what is called an Approach Header. You will see that the Approach Header has nothing to do with adding any lines to the GPS Receiver but it is more about what you hear from ATC when they are issuing vectors to final approach instructions.
We select from the Menu Approaches |Add Approach
A new screen pops up and allows us to edit the boxes
We edit the box so it is what the Chart says as per this picture
From the above picture, when I have the ILS listed for RWY 19R and the FAF as MULKY / IAF as LAUGH we then hit the add block.
That will place the Approach Header into our Tree Window like so.
I use the KIAD Approach chart to fill in some additional information. The Approach altitude feet is 2700 ft and the published missed approach altitude is 5000 ft as per the chart.
If I click on the Approach Leg IF statement I see that the information is already entered correctly in this picture.
If we were to save the .ade and compile, at this point ADE would generate a XML code that looks like the following. I will add some remarks to each of the lines of code.
<Approach type="ILS" <<<<<<------ What ATC says based on type approach listed
runway="19" <<<<<<------ What runway ATC says is the active for your arrival
designator="RIGHT" <<<<<------ What designator ATC says if one exist
suffix="0" <<<<<------- no suffix
gpsOverlay="FALSE" <<<<<------- no GPS overlay
fixType="TERMINAL_WAYPOINT" <<<<<<------ MULKY is a T_WAYPOINT
fixRegion="K6" <<<<------- Region code that KIAD is sitting in
fixIdent="MULKY" <<<<<------ The final approach fix that ATC is looking at (see Below)
altitude="2700.0F" <<<<<<------ ATC will tell you and the AI Plane what to descend to for the final approach
missedAltitude="5000.0F"> <<<<<----- What ATC assigns as the missed altitude if you or the AI Plane goes around
<ApproachLegs>
<Leg
type="IF"
fixType="TERMINAL_WAYPOINT"
fixRegion="K6"
fixIdent="LAUGH" <<<<<<< The Type Leg "IF" statement that ATC is working with (see below)
/>
</ApproachLegs>
</Approach>
There are 2 mandatory fixes that ATC is looking at which are the IF (Initial Fix LAUGH) and the FAF (Final Approach Fix MULKY). When ATC is vectoring you or the AI plane to final it is calculating a + - 30 degree offset heading from the TRUE runway heading. That means the intercept angle heading will always be 30 degrees either side the TRUE Heading (based on your direction to the aiport).
Ideally ATC is targeting a intercept to final approach between the IF and the FAF. However that also depends if you are the only one flying to the airport or if other AI Planes are flying to the airport. If you are the only one flying to the airport then be on your toes because ATC is going to vector you to intercept final just outside the FAF (MULKY). If 5 AI Planes are also landing then you the User are slotted into the string of arrivals and you may end up on final 25 NM from the runway at 2700 ft.
When any plane such as your plane or the AI plane reaches the FAF that is a triggering point for the Tower to say "you are cleared to land" first come first served. At that precise moment the Tower locks down the runway so no departures can takeoff. If another AI Plane overruns you it is now out of sequence since you crossed the FAF first. That AI plane will be told to go around since it is not in the correct slot.
The final point here is the Approach Header has to be there for any type approach you write. It is the instruction phase for all arrivals (except VFR flights which use different rules) that you hear ATC saying. The Approach Header has nothing to do with drawing any lines in the GPS receiver and those lines come from the next set of legtypes we will add plus the missed approach legtypes.