Curved/Rec Approach

lingyuan.he · 16 Jan 2013

Misc Questions about Approach

Hi,

I figured out the Arc myself, now I have some questions regarding approaches in ADE, it would be great help if someone can answer any of them.

1-Where should I put the DME of ILS(with GS or LOC)?
2-When using ILSDME for DMEArc, where is the center, the DME square in edit mode?
3-What is the difference between CF and DF, can I use DF freely in transition of missed approach legs?(I know I have to use CF in normal approach legs or after DMEArc)
4-Any differences when making transition and missed approach for RNAV instead of ILS or VOR?(I already know TF is the normal approach leg)

Any help will be greatly appreciated.

Thank you

Lingyuan He

jvile · 19 Jan 2013

lingyuan.he said:
Hi,

I figured out the Arc myself, now I have some questions regarding approaches in ADE, it would be great help if someone can answer any of them.

1-Where should I put the DME of ILS(with GS or LOC)?

FS9/FSX and ADE by default place the DME transmitter at the end of the LOC symbol. It is then up to us to move it to a more exact location as per charts. We cannot use the published Lat/Lon for the DME since it can be tuned from many different places (in real world) to show the Nmiles to the runway or Nmiles to the end of the runway.

If you are working from an existing approach chart then that tells you which end of the runway to set the DME at. If this is a made up approach it is your choice.

2-When using ILSDME for DMEArc, where is the center, the DME square in edit mode?

Do you have an example airport where the ILS DME transmitter is being used to create the DMEarc? The DMEarc is normally getting the arc info off a nearby VOR (see PHNL or KHUT)

3-What is the difference between CF and DF, can I use DF freely in transition of missed approach legs?(I know I have to use CF in normal approach legs or after DMEArc)

CF leg is Course to a Fix so it is used to the FAF and then to the runway for the ILS approach.

DF leg is Direct to a Fix so it is used from a unspecified track starting from an undefined position to a specific fix. These type legs (DF) normally follow a CA leg and then proceed to a fix.

4-Any differences when making transition and missed approach for RNAV instead of ILS or VOR?(I already know TF is the normal approach leg)

Not much difference. RNAV approaches will in most cases have their own IAF/FAF terminal_waypoints

lingyuan.he · 20 Jan 2013

jvile said:
If you are working from an existing approach chart then that tells you which end of the runway to set the DME at. If this is a made up approach it is your choice.

The chart shows that the ILS glide slope and ILS DME are installed together, is that normal?

jvile said:
Do you have an example airport where the ILS DME transmitter is being used to create the DMEarc? The DMEarc is normally getting the arc info off a nearby VOR (see PHNL or KHUT)

Here it is:

jvile said:
DF leg is Direct to a Fix so it is used from a unspecified track starting from an undefined position to a specific fix. These type legs (DF) normally follow a CA leg and then proceed to a fix.

So can I use thing like IF-DF-DF in Transition?

jvile · 20 Jan 2013

The chart shows that the ILS glide slope and ILS DME are installed together, is that normal?

In that chart yes its normal. The ILS is a ILS DME and the DME is IDENT ILL. The chart is showing that the DME is located at the threshold of the runway.

1. If you want the DME to read zero at touchdown then place it at the GS.

2. If you want the DME to read zero at runway threshold then place it next to the beginning of the runway off to the side a small amount.

At the bottom of the chart the DME NM on glideslope will show the DME is probably at the threshold of the runway but 1 or 2 above will work.

DMEarc Transition-------------

The DMEarc for Transition IAF D12.0 ILL is getting the 12 NMiles from the LH NDB using the 254 degree radial. So instead of using a VOR to reference the arc you use the NDB.

In the AF leg the Theta degree will be close to 333 degrees
Rho will be 12NM.
The course is mag so it will be 254.

Use the helper guideline (looks like a ruler symbol at the top of the ADE screen in approach mode) to draw a line 12 Nmiles long on the 254 degree radial from the NDB. This will be where you add a fake Terminal_Waypoint unnamed (your choice). This unname can also be the name of the Transition since the chart does not have one. Transition Altitude is 900 km

Use PHNL ILS 08 transition ALANA as an example for building the arc but place the NDB as the reference for the DMEarc instead of a VOR (see pic below). The ALANA Transition is very close to what you want but its arc is 14 DME from the VOR (AF leg) and you want 12 DME from the LH NDB.

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So can I use thing like IF-DF-DF in Transition?

No

Which transition out of the 5 shown on the chart would you want IF DF DF if you could use it? Just a reminder. You build a foundation ILS approach and then all Transition last legs be it a CF, TF, VI, PI, etc. attach to that foundation ILS IF (Initial Fix) as their last leg. Each Transition is an extension of the main ILS approach.

lingyuan.he · 20 Jan 2013

jvile said:
Which transition out of the 5 shown on the chart would you want IF DF DF if you could use it? Just a reminder. You build a foundation ILS approach and then all Transition last legs be it a CF, TF, VI, PI, etc. attach to that foundation ILS IF (Initial Fix) as their last leg. Each Transition is an extension of the main ILS approach.

So, is it correct that only use DF after CA, otherwise they are CF (in app leg or transition leg of ILS)?

Then same with VORDME NDBDME?

If making CF leg like IIL D10.4 to IF ILL D10 that without a indicated course, I just guess the course degree?

And one last thing, how can I make NDB approach?I can't even locate the non-precision waypoints.

jvile · 21 Jan 2013

hello lingyuan.he

Have you added all the fake Terminal_Waypoints at each of the x's

I count 8 total.

That chart and all those approaches are based on a DME and a degree from a runway and NDB. This is what makes all those x's. FSX does not understand the line draw from just a DME and degree.

When a intersection or x is on a chart you must add a fake Terminal_Waypoint to that intersection or x. Once all the fake Terminal_Waypoints are in there proper place then you connect them with the proper leg type to get the line draw in the GPS.

My answers keep going in circles until I know you have added all 8 fake Terminal_Waypoints.

What airport is this? It would help so I could add T_W's at the x's and show pictures that would help you.

lingyuan.he · 22 Jan 2013

jvile said:
Have you added all the fake Terminal_Waypoints at each of the x's

Yes i did, the DME location is at the side of the runway instead of at the end of the runway. I use actual DME location as the center of DME arc and placed a guide. Then combine with the relative location of the NDBs, I find the cross points using helper guides and placed all the waypoints.

However, something odd happened when I connect them, the two-stage DME arc looks rather broken, I really suspect that ADE is using the localizer location as the center of ILS DME no matter where I actually place the DME.

jvile said:
What airport is this? It would help so I could add T_W's at the x's and show pictures that would help you.

This is ZGZJ, a regional airport in China. I'm afraid you won't find a Jeppessen Chart. That's also why FSX is missing a lot of Chinese small airports.

jvile · 23 Jan 2013

lingyuan.he

However, something odd happened when I connect them, the two-stage DME arc looks rather broken,

That is because you have 2 AF legs in the arc. You are only allowed one per Transition. More on that further down.

I really suspect that ADE is using the localizer location as the center of ILS DME no matter where I actually place the DME.

The center location of the arc is the recommended Ident entry in the AF leg. If you expand the window Recommended Type you will see no DME is selectable. We cannot use the DME as the center point. Using the ILL Ident causes confusion on what to use and you are correct the localizer is trying to take precedence.

The good news

What we need is a center point for the arc. Since we don't have a NAVAID to use we add another fake Terminal_Waypoint on top of the DME symbol. This Terminal_Waypoint has no other use then a reference for the center point.

My numbers and yours may vary a small amount based on where we both have the new runway for ZGZJ. I placed the runway as best I could as per Google Earth. I also wanted the IF34 to be exactly 10 DME from the runway and over the water based on what the chart shows.

This pic shows were my runway is located since it is important the 12 DME arc crossover the land and water in the correct location.

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In the next pic I show drawing my helper lines to place the Terminal_Waypoints. remember I added a MA34 Terminal_waypoint at the same location as the DME and the 12 NM lines are coming from that location. In the AF leg I used the Terminal_Waypoint as the Recommended Type and the MA34 as the Recommended Ident.

The XML looks like this

<Transition
transitionType="DME"
fixType="TERMINAL_WAYPOINT"
fixRegion="ZG"
fixIdent="IAF34"
altitude="2000.0F">
<DmeArc
radial="95"
distance="12.0N"
dmeRegion="ZG"
dmeIdent="MA34"/>
<TransitionLegs>
<Leg
type="IF"
fixType="TERMINAL_WAYPOINT"
fixRegion="ZG"
fixIdent="IAF34"
/>
<Leg
type="AF"
fixType="TERMINAL_WAYPOINT"
fixRegion="ZG"
fixIdent="JZ102"
turnDirection="R"
recommendedType="TERMINAL_WAYPOINT"
recommendedRegion="ZG"
recommendedIdent="MA34"
theta="153"
rho="12.0N"
magneticCourse="93"
/>
<Leg
type="VI"
magneticCourse="270"
/>
</TransitionLegs>
</Transition>

Each IAF on the chart is a new Transition to the ILS. If you want the LH287 IAF Transition you must add another set of DME Arc legs. I see 5 IAF's so you would add 5 transitions to the ILS foundation code.

Use the VI as the last leg in a arc (no overshoot). The CF causes a overshoot as seen in the next picture. Also the VI is adjustable for the ending arc and automatically attaches to the IF34 without coding it.

AACvirtual · 24 Jan 2013

Curved approaches

Many thanks for this Jim and linyuan.he. Jim, if I use this as a template [the method rather than this actual approach], will this be the method for creating curved AI approaches to prevent AI from flying into mountains when positioning for approaches? In effect trying to replicate a Kai Tak type of approach? Charlie.

tgibson · 24 Jan 2013

No, because AI aircraft do not fly transitions...

In good weather they will only use an ILS approach (if present), otherwise they used an FS hard coded approach. But the only part of the ILS approach they use is listed in the main part of the approach - they do not fly any of the legs. They:

1. Approach the FAF (the waypoint listed in the main ILS approach section) from whatever direction they came from.
2. Cross the FAF at the altitude listed next to the FAF
3. Head away from the FAF at the heading listed there.
4. Start descending at a relatively constant rate to the runway elevation.
5. Turn to the runway heading when crossing the extended runway center line.
6. Land

So you can have two "bends" in the flight path - one at the FAF, and one at the extended runway center line.

Hope this helps,

AACvirtual · 26 Jan 2013

Curved AI approaches

Thanks Tom. Roger to that, If I get into trouble I will start a new thread. Sorry to butt in, and thank you, Charlie.