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Peabody

Airport Operations Questions Tower 3D

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In my attempt to earn my "Apprentice Pedantic merit badge" I have been listening to LiveATC for KLAS. At the same time I have FlightRadar24 map on so I can follow along with the actual flights.

I saw that KLAS has two towers and two departure frequencies listed.  I listened to the 8/26 tower so all departures were from 26R. Arrivals 26L. (There were some GA departures and arrivals on 19s but I did not hear that since it is the other tower)

Sometimes upon takeoff the tower will tell a plane "Contact Departure" .  At other times I will hear "Contact departure 125.9" OR "Contact Departure 133.95" , so I started selecting the plane in FlightRadar and jotting down the destination then watching the flight path.  So as some of you probably already know, 125.9 was given to planes that turned South, and 133.95 was given to planes that turned north. So naturally I assumed that each controller had a different section of the sky. Correct?

To clarify the above by sometimes they do and sometimes they don't give a frequency, I meant listening at totally different times or even different days, it was NOT a mixture during the same session.

So my main question: Do they give the frequency when they are busy and using both departures so the plane will contact the correct one?  Or is it simply that some Tower controllers give frequencies and others do not.  Or is there some other reason for the difference.

Thank you for any info.

Pwabody

 

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Typically, most aircraft departing from a large airport like LAS will be flying a SID (Standard Instrument Departure procedure).  On these SIDs all kinds of information is listed, and that often includes the Departure frequency for their route of flight.  Aircraft receive their ATC Clearance ahead of time, prior to taxi.  The clearance includes such things as the route, altitude, headings, frequencies (departure), and the "squawk code" for the transponder.  Sometimes the clearance can be incredibly brief and may not include everything because a lot is given on the SID...

For example, a clearance from LAS might be something like:

"N123AF, cleared to Los Angeles International airport via the BOACH8 departure, Hector transition, Climb Via the SID, expect FL280 in 10 mins, squawk 5521."

  • No initial altitude was given because a "Climb Via SID" clearance was given.  The SID has a "Top Altitude" of FL190.  The aircraft is cleared initially up to that altitude, but it must still comply with the altitudes listed during the climb out.
  • No frequency was given because the frequency was listed on the SID.

Clearances can be long, or they can be pretty brief.  

But to answer your question: if the tower is giving a departure freq, then it could have been a last-minute change; maybe a change in departure routing, or maybe the airspace is so congested they're opening up additional frequencies for workload management.  Doesn't happen all the time, but it is certainly common for that to happen.  Usually they'll give us the new frequency prior to takeoff, but it can happen both ways.

 

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Thought I'd throw this out as well since many of you like to listen into LiveATC!  If you're listening to the Clearance frequency and you don't hear a lot of airlines, cargo operators, and some GA aircraft calling for their clearance, it's because the system is changing.

Many aircraft are now capable of PDC (Pre-Departure Clearance) or CPDLC (Controller-Pilot Datalink Communication).  I think I got my acronyms right, lol.

Both of these allow pilots to receive their clearance, digitally, from ATC without ever needing to contact them....and tie up the frequency!  You might simply hear "United 1234, information Alpha (ATIS), squawk 5521."  

With CPDLC, pilots and controllers can exchange information, flight plans, requests, etc. without having to verbally talk to each other. It's really only into effect (USA) for departure clearances right now.  Starting next month, they'll begin to implement this stuff across the country for in-flight purposes.  Really cool stuff, actually.  CPDLC/FANS 1A is being used across oceans already, so planes flying across the pond don't really need to verbally talk to anyone unless the data stuff fails, or they just think a verbal request would be easier.  

So, back to my point, you may not hear a lot of clearances read for every aircraft.  A lot of GA airplanes will still be getting their clearance verbally for sure.

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1 hour ago, CL30 said:

But to answer your question: if the tower is giving a departure freq, then it could have been a last-minute change; maybe a change in departure routing, or maybe the airspace is so congested they're opening up additional frequencies for workload management.  Doesn't happen all the time, but it is certainly common for that to happen.  Usually they'll give us the new frequency prior to takeoff, but it can happen both ways.

 

 

 

Thanks for all the info, I appreciate it !!!  I read my post again and now this part of your answer, and I don't think I gave the information very clearly.

I was talking about commercial airlines on 26R,  The tower was, plane1, contact 125.9, plane 2 contact 125.9, plane 3 contact 133.95, plane 4 contact 125.9, plane 5 contact 133.95 and so on.  And every plane gets a frequency which seems to be according to whether he/she is going north or south and this will go on the entire time I am listening maybe 1/2 hour to 1 hour.   I was not listening to the Tower for GA flights coming off 19.

Then the next day I will tune in and all I hear is "contact departure", although when this happens I have heard "Departure now 125.9" and then more "Contact Departure" suggesting to me a change which I think is what you mean from the above statement. They were probably using 133.95 then changed to 125.9. 

As for your comment about the GA traffic, thanks for that info too.  They have been departing on 19s which is controlled by the other tower which I have not been listening to.  I will hear, AirlineXXX Line up and Wait, traffic departing/arriving intersecting runway" and i can see the GA leave on 19R. But I don't know about the Departure since I am not listening to that tower.  I will listen to both next time and see what they say.

Just trying to learn how this stuff works, could add some realism to  my game play the more I understand.  ATC-Joe got me to stop giving taxi instructions on pushback.  Then I stopping  adding altitude and contact departure to the takeoff clearance. The one problem I still have is Windows 7 will not say "Wind" as is weather, it says "Wind" as in wind up an alarm clock. Very annoying.

Thanks again for all the info, just that one section above I don't quite know if we are talking about the same thing.  The tower is giving every plane one of the two departure frequencies.  I know all planes that take off get a departure frequency somehow, from someone.   The ones I was wondering about is like I stated above, every plane being given  a frequency during "Contact Departure #####".  I didn't know if that was KLAS procedure.  I would have thought they would know who to contact before they took off, like you stated in your response.

I hope I make sense here.

Thanks again.

Peabody

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4 minutes ago, Peabody said:

Thanks for all the info, I appreciate it !!!  I read my post again and now this part of your answer, and either I asked the question wrong or I don't understand the answer.

Just for more info, the frequency did not change, which I know can happen.  It was plane1, contact 125.9, plane 2 contact 125.9, plane 3 contact 133.95, plane 4 contact 125.9, plane 5 contact 133.95 and so on.  And every plane gets a frequency which seems to be according to whether he/she is going north or south and this will go on the entire time I am listening maybe 1/2 hour to 1 hour. 

Then the next day I will tune in and all I hear is "contact departure", although when this happens I have heard "Departure now 125.9" and then more "Contact Departure" suggesting to me a change which I think is what you mean from the above statement. They were probably using 133.95 then changed to 125.9. 

As for your comment about the GA traffic, thanks for that info too.  They have been departing on 19s which is controlled by the other tower which I have not been listening to.  I will hear, AirlineXXX Line up and Wait, traffic departing/arriving intersecting runway" and i can see the GA leave on 19R. But I don't know about the Departure since I am not listening to that tower.  I will listen to both next time and see what they say.

Just trying to learn how this stuff works, could add some realism to  my game play the more I understand.  ATC-Joe got me to stop giving taxi instructions on pushback.  Then I stopping  adding altitude and contact departure to the takeoff clearance. The one problem I still have is Windows 7 will not say "Wind" as is weather, it says "Wind" as in wind up an alarm clock. Very annoying.

Thanks again for all the info, just that one section above I don't quite know if we are talking about the same thing.  The tower is giving every plane one of the two departure frequencies.  I know all planes that take off get a departure frequency somehow, from someone.   The ones I was wondering about is like I stated above, every plane being given  a frequency during "Contact Departure #####".  I didn't know if that was KLAS procedure.  I would have thought they would know who to contact before they took off, like you stated in your response.

I hope I make sense here.

Thanks again.

Peabody

I think I get what you're saying now, and yeah, maybe it is controller preference??  I really don't know that side of it, unfortunately. You're right about the departure frequencies being split depending on direction/procedure though.  It could be that they keep saying the frequency to contact as a means to "help" the pilots out and not get confused on which one they should contact.  Hmmm...

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Thank you again CL30, I was editing my response as you posting this answer, so I'm glad you got it.  You would think at 67 Yrs old I would be able to explain myself better LOL.  I know just enough about this topic to be a pain at asking questions.

Peabody

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1 minute ago, Peabody said:

Thank you again CL30, I was editing my response as you posting this answer, so I'm glad you got it.  You would think at 67 Yrs old I would be able to explain myself better LOL.  I know just enough about this topic to be a pain at asking questions.

Peabody

No problem at all, really!  I know what you mean though, haha!  I have to read, re-read, and re-re-read my posts anymore because I go off on the most random tangents sometimes.  No harm, no foul, and I'm always happy to talk aviation!  😁

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8 hours ago, Peabody said:

The ones I was wondering about is like I stated above, every plane being given  a frequency during "Contact Departure #####".  I didn't know if that was KLAS procedure.

Doesn't seem to be a standard procedure. Could be controller preference, could be depending on whether the crew got the departure frequency from clearance delivery, but could also be anticipation whether the pilot is familiar with the airport and airspace and coming in regularly (especially those with KLAS as base - pilots from Southwest and Allegiant seem a safe bet - might be able to tell the frequency while sleeping). I mean, when a pilot or F/O calls time and time again, you surely start to recognize him/her by voice and tone...

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I think it is either controller preference, the controller confirming a possible deviation from the chart, or combined frequencies. For example while I'm typing this post this morning everyone (regardless of departure runway and departure heading) was being sent to 125.9.  There appeared to be only one tower controller and I assume only one active departure controller. 

FYI - there were several STAAV8 departures which would normally be sent to the 133.95 departure frequency.

 

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At 67 Peabody, you are entitled to be Pedantic!

Nice to know there is another person that likes to get things as accurate as you can even if it's only a game!

Welcome to the Pedantic club matey 😁

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27 minutes ago, Pedantic G said:

At 67 Peabody, you are entitled to be Pedantic!

Nice to know there is another person that likes to get things as accurate as you can even if it's only a game!

Welcome to the Pedantic club matey 😁

Thanks Pedantic G  LOL.  I just enjoy learning. I was just listening to KLAS (again) and they had a go around, and then told a departing plane it just lost its "slot" for San Diego because of the delay caused by the go around, so he had to hold for about 10 minutes.........who can figure all this out? 

BTW, do we get secret decoder rings in the Pedantic club?

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55 minutes ago, Braf123456 said:

what is a Pedantic club

It's just a bit of fun and banter!

Official meaning of PEDANTIC is:

"excessively concerned with minor details or rules; overscrupulous. 

😉

 

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1 hour ago, Peabody said:

BTW, do we get secret decoder rings in the Pedantic club?

Maybe we can get Vic to give us special emoji's to use as a code!!! 🤣

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4 hours ago, Peabody said:

BTW, do we get secret decoder rings in the Pedantic club?

You also have to change your name to Pedantic P, and think of some type of coded (virtual) handshake 😄

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1 hour ago, hexzed said:

You also have to change your name to Pedantic P, and think of some type of coded (virtual) handshake 😄

But I'm still in training, I'm not full Pedantic yet 🤔

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