FS2004 Setting Comms Arrival/Approach Channel

[danfoster]

FS9 has multiple approach comms frequencies listed in the AFDs of many larger airfields.

In the days of AFCAD, it was possible to determine which "Arrival/Approach" frequency was active, by ensuring it was listed above/before the alternative approach frequencies in the "Comms" list.

I notice that in ADE, this list order is not respected - the frequencies do not display in the same list order as if I viewed the same file using AFCAD. Therefore, it is no longer possible to determine which Approach channel is active by simply moving that channel up the list.

Is there a way to set this in ADE, other than by deleting the redundant channels?

Cheers,

Dan

 

[scruffyduck]

So you are looking for re-ordering of comm frequencies in the list? This is not available but, of course, we could look to add it.

 

[tgibson]

I think it's more serious than that - he says it appears that ADE does not list the frequencies in the order that gives them priority in FS, unlike AFCAD that does.

Hope this helps,

 

[scruffyduck]

I think it's more serious than that - he says it appears that ADE does not list the frequencies in the order that gives them priority in FS, unlike AFCAD that does.

Hope this helps,

OK and what order is that?

 

[danfoster]

Hi Tom,

I mean it exactly as you describe it

AFCAD lists them in a way that indicates their priority - ie. which one will be used in FS9.

ADE lists them in a different order - one which therefore does not indicate priority. Further, even if ADE did list them in order of priority, it is not possible to change their order anyway (within ADE).

I hope that is a little clearer

 

[scruffyduck]

Hi Tom,

I mean it exactly as you describe it

AFCAD lists them in a way that indicates their priority - ie. which one will be used in FS9.

ADE lists them in a different order - one which therefore does not indicate priority. Further, even if ADE did list them in order of priority, it is not possible to change their order anyway (within ADE).

I hope that is a little clearer

Right but my problem is that I am not clear what order that is. ADE lists them in the order they appear in the XML source. Clearly there is some other order that I am not clear about

 

[n4gix]

I haven't actually come across this issue myself, but I have to ask...

...aren't the approach com freqs simply listed in the same order they were entered to begin with?

IOW, wouldn't the first entry become the 'primary freq' and all subsequent entries be treated as 'alternative' or 'secondary' freqs?

 

[scruffyduck]

I haven't actually come across this issue myself, but I have to ask...

...aren't the approach com freqs simply listed in the same order they were entered to begin with?

IOW, wouldn't the first entry become the 'primary freq' and all subsequent entries be treated as 'alternative' or 'secondary' freqs?

That is what I thought Bill - but it seems more involved than that......

 

[jvile]

Hi Tom,

I mean it exactly as you describe it

AFCAD lists them in a way that indicates their priority - ie. which one will be used in FS9.

ADE lists them in a different order - one which therefore does not indicate priority. Further, even if ADE did list them in order of priority, it is not possible to change their order anyway (within ADE).

I hope that is a little clearer

The AFCAD listing of Arrival and Departure freq's is nothing more then a numerical listing.



You can do the same thing in ADE by clicking on the Airport tab at the top of the list.



However none of this sets a priority in which freq is the one that will be used first. FS9 scanned arrival and departure freq's the same as what was listed on freq charts per airport (April 2002). There are many zone sectors in a radius around large airports that extend outward about 60NM's for the approach / departure phase of flight (Center extends outward from 60 to 108NM's).

Based on which zone you enter and the altitude you are at determines what arrival freq will be assigned when there are multiple choices.

If you build a airport from scratch and add multiple approach/departure freqs then FS chooses the first one listed and disregards all others since the compiled XML cannot add itself to the freq boundary files that are coded by FS.

 

[danfoster]

Hi Jim,

My version of AFCAD on my XP system operates in direct contrast to what you have stated:

The list order of frequencies in the Comm List window is always maintained, and the first Approach channel is always the active Approach channel within the 20 mile radius below 10,000 ft (assuming no other AFD's with Approach channels in the vicinity).

Further, channels are not listed in numerical order of frequency value - whether default or modified:


To verify, here is the default EGLL with the comm list order displayed (note the last two APP freq):


I didn't realise that not all versions of AFCAD were the same on all systems. So it seems that my version treats the Comm list order differently to yours, and that the control I have over which frequency is the active perhaps cannot be replicated on your set-up.


Cheers,

Dan

 

[scruffyduck]

Well I guess the bottom line is - if someone gives me a spec for the required behavior I will try and implement it !

 

[danfoster]

That would be great John, if possible

I just had an idea: Maybe the illegal character(s) that AFCAD inserts into the comm data has something to do with this? But I can only guess...


I'm afraid I have no idea how AFCAD is able to prioritise one arrival frequency over another. How AFCAD compiles this info into the bgl is for someone else to answer. All I know is that it is always the first arrival frequency in the AFCAD comm list that is the "active" arrival channel for that AFD file. I have often effectively "swapped" the active channel for an inactive channel, although in practice what this actually amounts to is simply editing the frequency (and c/s if necessary) of the first-listed arrival channel. So I realise that stating I have changed the order (or "swapped" channels) in the afcad list is misleading - it is not possible to change the afcad comm list order: all I have ever done is just edit the first-listed arrival channel, and this has always affected the behaviour of FS9 as expected. Editing the other arrival channels changes nothing, as they are not actively used within FS9.

For further clarity (and to help reveal if there is a flaw in my understanding):

None of what I'm referring to has anything to do with boundaries and the like. Within FS9, there may be a number of r/t channels that "control" you when you are in the approach phase of flight. When you are above ten thousand feet OR further than thirty NM from a non-modified stock airfield (twenty NM from a modified airfield) with an "arrival" channel, you will be under the control of an ATC "Center/Control" channel dependant on boundaries as specified in the "bvcf.bgl" file. But if you are below ten thousand feet AND within thirty NM of an arrival-channel-equipped stock airfield (twenty NM of an arrival-channel-equipped modified airfield), then you will be under the control of whichever arrival-channel-equipped airfield is nearest to your current location, irrespective of whether that is your destination or not, and irrespective of the boundaries in the "bvcf.bgl" file. As you continue your approach, you may well be passed between different arrival channels, always dependent on which arrival-channel-equipped airfield you are nearest to. And if your destination itself is not an arrival-channel-equipped airfield, you may even be handed over to a "Center/Control" channel if your range to the nearest arrival-channel-equipped airfield becomes greater than 30 NM (20NM for modified airfields). Only when you are cleared for the final approach will you be handed over to the "tower" (or equivalent) channel of your destination airfield.

Now, your nearest arrival-channel-equipped airfield may have a number of arrival frequencies listed within the AFD data, but only one will ever be used by FS9. Somehow, AFCAD knows how to identify which one this is, and it will always list it above any other arrival channels in the comm list. If you want to change the arrival channel for this airfield in any way (perhaps to reflect changes in the real world), then you must edit the arrival channel that FS9 uses for this AFD. So changing any arrival channel details must be done to the first listed arrival channel. Changing any of the others has no effect.

What would be good to see in ADE is a way of identifying which arrival/approach channel is the "active" approach channel, so that one can know which one to edit when needing to make changes.

I hope you strike lucky in finding out how to do this

Cheers,

Dan

 

[danfoster]

Just wondering if anyone has "struck lucky" yet...

 

[rfields]

Let me see if I understand this correctly and I will use the EGLL example above.

Are you guys saying that if I open the default EGLL FS9 airport with AFCAD and go to the Comms list - move the 125.625 frequency to the top of the Arrivals frequency list - that frequency will become the approach frequency used within 20 nm of the airport to the exclusion of the others?

 

[jvile]

Dan

Have you tested any large airport both high and low altitude for the USA. In smaller Country's the first listed channel may be the one that Approach uses but this is not consistant with other airports throughout the comm database.

I will show you a simple test airport for you to try. Flightplan is IFR from KDAB (Daytona) to KJAX (Jacksonville) at 3000 ft using the Beech Baron. Winds are from the South so runway 13 ILS is active at KJAX.

The first picture is the comm list for KJAX FSX ADEX. The second picture is comm list for KJAX FS9 using AFCAD. They are the same.

During my flight at 3000 ft I am told to contact Jacksonville Approach which will be my first communication with them on freq 118.175. Looking at the following list there is no 118.175 listed.





We set ADE to display all airports and Comm's within a 30 NM radius of the airport you load (Approach Mode greater then 60NM's). ATC Approach works on a 60 NM radius of an airport so many of the Approach Transitions can be selected before the User Plane passes the Navaid IAF entrance point.

When you ask Approach for a Transition you want to be sure that Transition is out in front of you so the Pilot does not have to do a 180 turn back to the IAF of the Transition.

So where did the Jacksonville Approach Comm 118.175 come from if not within 30 NM's of KJAX. It came from an airport 55NM's south of KJAX. The airport is Larkin (28J) and I have to use ADE to load it in order to see the approach freq's.



What good would it do to edit any of the actual listed Jacksonville Approach Comm freq's if the very first communication with Jacksonville Approach is 55NM's away.

When I got within 60 NM's of KJAX Center gave me 118.175 as the first approach freq. Since the winds are from the south I will have to fly pass KJAX and approach will vector me to a reversal final to runway 13. The list of approach freq's during my flight are as follows

118.175
120.750
123.800
118.600

and now I am on a 30 degree offset heading to final approach course and KJAX approach tells me to intercept ILS and contact Tower on 118.300.

The first listed approach freq for KJAX is 118.00 as per AFCAD and ADE9X but I was never given that freq on my approach. I was finally given 118.600 (2nd on the list) but it was the 4th freq that approach assigned me on my arrival.

High altitude using a Lear Jet at 14,000 ft and I was assigned Jax Approach 123.80 all the way to the airport and then told to contact tower.



Another small test for Heathrow

Depart Shoreham in a default Cess 172 IFR to EGLL at 3000 ft., winds from the east. Approach freq's are as follows

Shoreham 123.15
Dunsfold (which is also what Gatwick is using) 135.175
Farnborough 125.25

now told to contact Heathrow Tower for arrival on 9R

At no time did ATC ever have me contact a actual Heathrow Approach freq so again it would be useless to edit any of those actual listed freq's in the Heathrow list for a IFR flight at 3000 ft. from Shoreham.

What I am trying to show is this is the way that FS was set up for many airports. I am not disagreeing with what you may see for some airports but we have to have some kind of consistency if you are going to say the first listed Approach Comm is the one that ATC always uses.

 

[danfoster]

Hi folks,

I can only comment on FS9, and I appreciate that many have moved on. So if FSX works differently in this regard, then the feature I'm asking for in ADE is probably only relevant to ADE9.

Let me see if I understand this correctly and I will use the EGLL example above.

Are you guys saying that if I open the default EGLL FS9 airport with AFCAD and go to the Comms list - move the 125.625 frequency to the top of the Arrivals frequency list - that frequency will become the approach frequency used within 20 nm of the airport to the exclusion of the others?

Almost. You cannot actually move/change the order of channels in AFCAD's com list, but you can edit the highest-listed approach "arrival" channel to whatever you wish (both freq and calsign, provided you have the relevant voice files).

Now, in FS9, If you are

1) within 20 nm range
AND 2) this modified afcad is the nearest approach "arrival" r/t channel equipped facility to your current position
AND 3) your altitude is less than 10,000 asl,

Then this will be the AFD file that provides your ATC channel when flying IFR.

If you have changed the details of the highest-listed approach "arrival" channel, Then you should notice this within FS9, provided the three above conditions obtain.

(I've been reading logic recently )


Jim, I will do your tests in due course and report back. I'll also answer some of your points individually when I get a chance. Thanks for the detailed post

 

[jvile]

Now, in FS9, If you are

1) within 20 nm range
AND 2) this modified afcad is the nearest approach "arrival" r/t channel equipped facility to your current position
AND 3) your altitude is less than 10,000 asl,

Dan

I have to ask, how did you get within 20 NM's of your destination on a IFR FP without ever talking to approach once center handed you off when 60 NM's from the airport.

If I understand your statement you want to fly to a airport on a IFR FP but not contact approach until within 20 NM's and less then 10000 ft.

 

[danfoster]

Sorry Jim, I didn't explain well and as a result, you completely miss understand me

What I am talking about is which control channel you will be in contact with at a given point.

I am not talking about who you talk to in the earlier stages of your approach, although I did briefly mention the way in which you are sequentially handed between various controllers as I was trying to illustrate a supporting point.

Now for the purposes of an ADE or AFCAD produced bgl that contains an Approach/arrival channel, you do not have control over what ATC channel will be talking to approaching aircraft for most, possibly all, of the approach. As you have indicated, this will depend on many different variables relating to airspace boundary records in the stock files.

But, take a stock airport (ie. one with no afcad present in FS, only the stock AP file) in the middle of nowhere, at least sixty miles from its nearest neighbour. This airport must also have an approach channel in its com record. Now do a test in FS9: After noting the approach r/t channel details, fly around in the aircraft in the vicinity of this airfield. You will find that as long as you are below 10,000 ft and within 30 nm range, you will be in contact with the approach channel for this airfield. If you go higher than 10,000 ft, you will be handed off to the Centre freq. Or, if you go beyond 30 nm range, you will also be handed off to the centre. But as long as you stay within 30 nm, and below 10,000 ft, you will be under the control of the Approach channel listed in the com record of this airfield.

OK, so what happens if there are two nearby airfields with an approach channel in their com records? Well, its similar to the above, except that when you are within 30 nm of both airports, you will always be under the control of the nearest airport to your current position. If you were flying between the two airports, you would be handed from one ATC to the other ATC as you approach the midpoint of your route. Basically, the boundary of influence of the two airfield's ATC Approach controllers is defined by an equidistant line between the two airfields, extending away from the airfields in either direction until it ends at 30 miles range (from both airfields - this being the equidistant line).

And the same principles apply if you introduce more airfields to the scenario provided these airfields are "approach/arrival" channel equipped.

The result is that if you are below 10,000 ft , you will always be talking to the "approach" controller as defined in the com record of the nearest approach-channel-equipped airfield to your current position. The only exception to this is if there are no approach-equipped airfields within 30 nm of your current position, in which case you remain with whatever "centre" controller is defined for your position in the bvcf.bgl. So as you fly your meandering vector approach procedure to ANY airfield in the world, when you descend below 10,000 ft, this rule comes into play. Each time you are handed between controllers, it is because you are now nearer to a different approach-channel-equipped airfield. When you are handed over to another controller (not including the "centre"), make a note of the r/t channel freq and callsign. Now pause FS9, look in your GPS and identify the nearest airfields to your current position. Open up the AFDs using AFCAD, and check through them (checking the nearest first), you will find that the nearest two approach-channel-equipped airfields are the two airfields between whose ATC you are being handled. The previous channel will be in the AFD of the airfield you are flying (vaguely) away from, and the new channel will be the airfield you are are flying (vaguely) towards. And if your route takes you to an area where there is no approach-channel-equipped airfield within 30 miles of your current position, you will be handed off to the "centre" controller (as defined in the boundaries in the bvcf.bgl file) once more.

Now back to using AFD files to influence ATC: If you confirm my above findings, you will see that there are certain areas of airspace under 10,000 ft that are under the control of ATC channels specified in the com records of the stock AFD data (as opposed to other airspace and boundary data). Now, in this limited sphere of influence, it is possible to determine what ATC channels will be active, by looking at the AFD com records of airfields that are approach-channel-equipped. Further, it is also possible to change this data with programs such as AFCAD. Which means it is possible to set the correct ATC channels within these 30 nm spheres of influence. (Aside: any modified AFD files that specify Approach channels have their "sphere of influence" limited to only 20 nm. Therefore, if you have modified the test airfield in my example above - ie. it now has an afcad file, you now have to be within 20 nm not 30 nm to be in contact with its approach controller.)

So it is only this close range low-level airspace that I hope to be able to influence when I design AFDs (whether using AFCAD or ADE). I do not hope to set the ATC channels for the earlier higher altitude sectors of the approach.

Does that make my intention any clearer?

 

[danfoster]

Hi again Jim,

It's also possible that I misunderstood your last post

ATC does not hand me off when I'm sixty miles from my destination in FS9 (I don't own FSX).

It hands me off as my descent approaches 10,000 ft. Are you saying my FS is corrupt? - cos that's a possibility...

I don't "want" to fly to a airport on a IFR FP but not contact approach until within 20 NM's and less then 10000 ft. But that is what happens if I am in a deserted part of the world.

A key thing to realise is that the ATC you are in contact with has nothing to do with your destination (until you are told to "contact tower..." on final approach). Assuming you are under 10,000ft, it is determined purely by your position in relation to nearby approach-channel-equipped airfields. You will always be in contact with the nearest of these (if within 30/20 nm). (This can occasionally be slightly confusing, as there are certain cases where airfields that in real life do not operate approach channels nevertheless have approach channels defined in the FS9 AFD com records. Usually these are cases where a nearby large airport's approach channel is listed in the com record of the smaller airport. As far as FS9 is concerned this is a seperate approach channel, even though it may share the callsign and/or frequency with the com record of the nearby larger airport. That can make it harder to identify where FS9 is getting its data from when you're under ATC control)

Hopefully you can make sense of my rambling...

 

[danfoster]

Hi again,

Jim, I finally got round to reading your earlier post (#15), and indeed that has confirmed we are talking at cross-purposes. But it also shows me that we are probably mostly in agreement as well!

Hopefully my posts above give a better indication of what I'm trying to express:

Basically, that every AFD that has an "Approach"/"Arrival" channel has ATC control over all nearby low-level traffic (under 10,000 ft and not on final app or in a vfr circuit), provided that the traffic in question is not closer to another nearby approach-channel-equipped airfield (if it were closer to a nearby approach-channel-equipped airfield, it would be under that airfield's control). In AFCAD, we can edit this channel to change the controlling ATC authority in the relevant sector (as I defined it in the posts above; namely an upright cylindrical column of airspace 20 nm radius and 10,000ft height - assuming no nearby approach-channel-equipped airfields are encroaching). This is what I want to be able to control when I design AFD files - making adjustments if necessary.

Now, bringing the thread back to its original posture: Some AFDs contain a number of "approach"/"arrival" channels. My claim is that when viewing the com record in AFCAD, I have only ever found that it is the first-listed channel that is the active ATC in the relevant sector of airspace.

I will have to investigate your claim that at KJAX, it is the second-listed channel, not the first. My initial theory is that when you were handed over to KJAX Approach on 118.600, you were in fact nearest to a different airfield, within whose com record was the channel of 118.600, listed at the top if viewed in AFCAD. But that is just a hunch, yet to be proven. I will have to go check it for myself.

Cheers,

Dan