I see multiple 'tower', 'ground', etc. frequencies on many AFCADS and was wondering if there is any benefit to this? Are they all operative. Some have 2 or even 3 frequencies for 'tower', 'clearance', etc. Just a curiosity question.

As far as I know, airports always have more than one controller :) And I also believe that those are used for FS9 ATC tuning.

I guess what I meant was there are duplicate 'tower', 'ground', etc. frequencies. Like KDFW has 3 'tower' frequencies. Do they all operate in the FS world or is only 1 needed.

A brilliant example is from the ITVV Virgin 747 dvd, and they get switched from one ground controller, to another. In MSFS, I believe the different frequencies do operate independantly. I'm sure I've been taking off on one runway, with one controller, and seeing dozens of landing aircraft on another runway and not hearing the comms. Thus meaning they must be on a seperate frequency. I've never come accross this with the ground freq's however.

I do not know how well FS ATC and other applications support this. The RW reason is to divide the functions by area or "sector" at large congested airports to reduce the workload on controllers.Typically different CDs will be available for different departure directions. Tower can be divided by the assigned runway and initial departure direction.These areas of jurisdiction are called sectors (just as enroute). Ground can be divided the same way where there is a division according to parking/ramp areas and you'll find one ground controller handling one side of the airport and another the opposite side. There can be different types of arrangements depending on runway and taxiway/parking arrangements.

>As far as I know, airports always have more than one>controller :) And I also believe that those are used for FS9>ATC tuning.Well, they didn't at Lexington / Blue Grass which led to RJ aircraft taking off the wrong runway and crashing.scott s..

Just checked it out in the sim at KLAX which was the first airport I could find that listed more than one tower frequency. What I found was that you can only use the frequency assigned by ground or approach. Say for example the info for the airport says tower frequency is "123.45 and 234.56". When you ask for permission to taxi ground will tell you to taxi to runway 9 and contact the tower on "123.45" when ready. When you reach runway 9 you can set your radio to the alternate frequency "234.56" but when you push the "~" key to bring up the ATC dialog the only option you will have is "Contact Tower on "123.45". So as far as I can tell in a short experiment the alternate tower frequencies are window dressing.

I think that may be true with the user aircraft. I did a little playing around and I'm seeing AI aircraft pushing back and getting taxi clearance from someplace. Sometimes I hear them but sometimes not, which tells me that AI's might be using multiple frequencies.I'm flying from KMIA to SBGL tomorrow so I'll check further.

Yes MSFS does use multiple tower and ground frequncies where applicable. At KLAX one tower freq is used for Rwys 6/24 L and R and the other for Rwys 7/25 L and R. They may use different ground control freqs also but I don't think you change ground freqs as you taxi from one side of the airport to the other. The RW KLAX diagram that I have says that real-world pilots do so.At KLAS one tower freq is for Rwy 25 R and a different freq for Rwy 25L. I seem to recall that two ground contol freqs are used at O'Hare. I'm sure that tere are many other examples.R-

The controller wasn't the cause of that accident. He also did not lead the RJ to the wrong runway.

Well you said Miami. They use different tower frequencys for 9 left and 8 right and 8 left. Where ever you start from a parked position will determine what ground frequncy you tune to and which runway you'll be directed to. I've sat at the end of runway 8 tuned to both tower fequencys at the same time. That can be a never ending dialog with lots of over talking. Bill

I didn't check that. Also you may be assigned one frequency one time and another the next time. I just taxied out to the runway and tried using the alternate frequency by tuning the radio to it.

Yes, I departed KMIA today for SBGL and leaving from Concourse A, I was directed to 8R. Other AI aircraft were being directed to rwy 9 on the other side and I never heard them so the dual ground/tower frequencies are working for the AI's. We'll see what happens in Rio.

There is coding which no one has been able to reverse engineer that FS uses in multiple frequency airports.At some different tower frequencies are used for landing/ takeoffs different runway pairs - like KLAX as noted above.At others one frequency is used for the runway operating in one direction - i.e Rwy 7R & 7L and another frequency for the opposite direction - Rwy 25R & 25L.Multiple ground frequencies tend to be assigned by where the aircraft is parked before asking for clearance - and the runway assigned.We haven't been able to add frequencies to airports and cut down on the traffic jams created by the over loaded comm channels.We haven't been able to add tower frequencies and relieve the go arounds and such caused by over loaded comm channels.Removing those 'extra' frequencies causes one of two effects - the first is that FS sees removing them as an error and ignores the 'bad' AFCAD; alternately the airport gets hung up because a runway or section of the parking area no longer has a frequency and the program coding does not move the aircraft to another frequency.Basically - it's a bad idea to remove them.

mmmm, that makes a lot of sense and the behavior of the AI's bears that out. thanks for putting some light on the subject.