Fly2HMO
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Reason For "Kilo" Being Appended To UA Callsign?

Mon Dec 06, 2010 2:47 am

I am monitoring the KIAD frequencies on LiveATC.net and just heard some flight referred to as "United 990 KILO" all throughout approach and landing. Never heard that before. It was a 752. The only thing out of the ordinary is that from what I looked up it was 75 minutes late, but last time I checked there were no special codes for late flights.

Been scourging like mad through the FAR/AIM and can't find anything on it. I'm sure there's some simple explanation for this. It was just one of those WTF moments and I was curious as to the meaning behind the KILO being appended.
 
Cubsrule
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RE: Reason For "Kilo" Being Appended To UA Callsign?

Mon Dec 06, 2010 2:54 am

Quoting Fly2HMO (Thread starter):
The only thing out of the ordinary is that from what I looked up it was 75 minutes late, but last time I checked there were no special codes for late flights.

That's actually precisely the reason. They can't have 2 Flight 990s on the ground at Dulles or in the air at the same time, so if 990 ORD-IAD is late enough that it might "overlap" with 990 IAD-ACC, they append the K to ORD-IAD so ORD-IAD is UAL990K and IAD-ACC is UAL990.

FWIW, it is possible to have two flights with the same call sign in the air in different places at the same time. When MQ filed their jet flights as 3 digit flight numbers, it happened sometimes (e.g. 3459 DFW-VPS was sometimes in the air at the same time as 4459 ORD-JAX; both filed as EGF459).
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Fly2HMO
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RE: Reason For "Kilo" Being Appended To UA Callsign?

Mon Dec 06, 2010 3:14 am

Quoting Cubsrule (Reply 1):

That's actually precisely the reason. They can't have 2 Flight 990s on the ground at Dulles or in the air at the same time, so if 990 ORD-IAD is late enough that it might "overlap" with 990 IAD-ACC, they append the K to ORD-IAD so ORD-IAD is UAL990K and IAD-ACC is UAL990.

FWIW, it is possible to have two flights with the same call sign in the air in different places at the same time. When MQ filed their jet flights as 3 digit flight numbers, it happened sometimes (e.g. 3459 DFW-VPS was sometimes in the air at the same time as 4459 ORD-JAX; both filed as EGF459).

Ah yes, that makes sense now, I did notice an equipment change for the next leg but the possibility of overlap didn't cross my mind.

Is it any random letter assigned by the airline itself or given by ATC?

I wonder if it's in the 7110.65... too lazy to go through the million pages though  
 
goboeing
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RE: Reason For "Kilo" Being Appended To UA Callsign?

Mon Dec 06, 2010 3:48 am

Quoting Fly2HMO (Reply 2):
Is it any random letter assigned by the airline itself or given by ATC?

I think the airline has the option of what to do. After all, they can make the callsign whatever they want as long as it's in the remarks section.

United seems to use K.

USAirways seems to use P.

My company drops the number completely and uses the four digit ship number as the flight number.

So they are all different.
 
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LAXintl
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RE: Reason For "Kilo" Being Appended To UA Callsign?

Mon Dec 06, 2010 4:24 am

From United's FOM:

Whenever there is the potential for two United airplanes to have the same flight number
while operating in the same airspace, a radio flight number is assigned to one of the flights.
Domestically and internationally, radio flight numbers use the base flight number (e.g., 165) with
an alpha suffix (i.e., A, C, J, K, L, T, W or Y) (e.g., 165A). For domestic flights, there may be
limited occasions where radio flight numbers in the 8100-8299 range are also used. This is
especially true if the original call sign is a four-digit number.
From the desert to the sea, to all of Southern California
 
Fly2HMO
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RE: Reason For "Kilo" Being Appended To UA Callsign?

Mon Dec 06, 2010 5:22 am

Quoting GoBoeing (Reply 3):

I think the airline has the option of what to do. After all, they can make the callsign whatever they want as long as it's in the remarks section.

United seems to use K.

USAirways seems to use P.

My company drops the number completely and uses the four digit ship number as the flight number.

So they are all different.

I figured, as ATC most likely doesn't really care as long as it's shown on the strip   

Quoting LAXintl (Reply 4):
From United's FOM:

Whenever there is the potential for two United airplanes to have the same flight number
while operating in the same airspace, a radio flight number is assigned to one of the flights.
Domestically and internationally, radio flight numbers use the base flight number (e.g., 165) with
an alpha suffix (i.e., A, C, J, K, L, T, W or Y) (e.g., 165A). For domestic flights, there may be
limited occasions where radio flight numbers in the 8100-8299 range are also used. This is
especially true if the original call sign is a four-digit number.

Interesting. So it's pretty much random then.
 
Maverick623
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RE: Reason For "Kilo" Being Appended To UA Callsign?

Mon Dec 06, 2010 6:59 am

Quoting Fly2HMO (Reply 5):
So it's pretty much random then.

While the alpha suffix can indeed be a random choice, each airline generally uses a specific one as a matter of tradition.

As was stated before, I've only ever seen US "A-sections" as we call them with a "P" attached. Mesa likes to use "A". Southwest doesn't use any, they refile with a 8000 or 9000 flight number.
"PHX is Phoenix, PDX is the other city" -777Way
 
Fly2HMO
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RE: Reason For "Kilo" Being Appended To UA Callsign?

Mon Dec 06, 2010 5:18 pm

Quoting Maverick623 (Reply 6):

As was stated before, I've only ever seen US "A-sections" as we call them with a "P" attached. Mesa likes to use "A". Southwest doesn't use any, they refile with a 8000 or 9000 flight number.

Ah gotcha. This thread has been enlightening.   
 
SPREE34
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RE: Reason For "Kilo" Being Appended To UA Callsign?

Mon Dec 06, 2010 6:03 pm

Quoting Fly2HMO (Reply 2):
I wonder if it's in the 7110.65..

Nope.

Quoting LAXintl (Reply 4):
From United's FOM:

You would most likely find their procedure refers to some part of CFR (FAR) Pt. 121.

Quoting Fly2HMO (Reply 5):
I figured, as ATC most likely doesn't really care as long as it's shown on the strip  

Absolutely correct!
I don't understand everything I don't know about this.
 
Brick
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RE: Reason For "Kilo" Being Appended To UA Callsign?

Tue Dec 14, 2010 2:24 am

I was on UA902 today DEN-IAD. The flight number continues on as IAD-MUC with a change of aircraft. We used a callsign of United 902 Charlie. I understand the overlaping flight thing, but we were the first UA902 operating today. Why did we get a suffix added to our callsign?
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PapaChuck
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RE: Reason For "Kilo" Being Appended To UA Callsign?

Tue Dec 14, 2010 3:32 am

I had to attach a letter to an AA callsign once when our computer, for whatever reason, had issues passing a flight plan from an adjoining Center. We just could not, try as we might, get the aircraft to track in our system (I think there was a duplicate entry somewhere). The solution was to create a new flight plan using an "A" at the end of the callsign. We gave the flight the new squawk code for the new flight plan and told them something along the lines of "American XXX, we had a problem with your flight plan, so from here on we're going to call you American XXX Alpha." Not the most graceful of solutions, but it worked.
In-trail spacing is a team effort.
 
PWMRamper
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RE: Reason For "Kilo" Being Appended To UA Callsign?

Tue Dec 14, 2010 5:24 am

How does it work with 4 digit flights numbers, ala RJs?

You can't have GJS 7358K, too many characters?
 
PapaChuck
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RE: Reason For "Kilo" Being Appended To UA Callsign?

Tue Dec 14, 2010 2:24 pm

Good point, 4-digit flight numbers are another issue since the system will only accept up to seven characters for an aircraft callsign. We'd have to be a little more creative. The first step would be do to some quick detective work and track down the flight plan with the duplicate flight number. If that flight is on the ground or has left our facility's airspace, the flight plan could most likely be deleted, removing the conflict. If that doesn't work, tell the flight crew about the problem and have them call dispatch so see if they can figure it out. Dispatch may come back with a new flight number or some other solution (we can't just change flight numbers on our own). If that doesn't work, we could change the callsign to something like GJS358A and make a note in the flight plan remarks that the flight is still operating as GJS7358. There really isn't a good way to solve a computer or a flight plan glitch. We just have to figure something out on the fly and make it work.
In-trail spacing is a team effort.
 
egph
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RE: Reason For "Kilo" Being Appended To UA Callsign?

Tue Dec 14, 2010 2:40 pm

Quoting GoBoeing (Reply 3):
I think the airline has the option of what to do. After all, they can make the callsign whatever they want as long as it's in the remarks section.

United seems to use K.

USAirways seems to use P.

My company drops the number completely and uses the four digit ship number as the flight number.

In the UK (I may of course be wrong as I am not as knowledgeable as some of the people here) "Papa" is only used by Positioning flights or other non passenger carrying flights where there is no "flight number" as such. I certainly hear Loganair flying around central Scotland with say "Logan 177 Papa", very often moving Saabs between their main bases at EDI and GLA up to DND.

Also I remember about 5 or 6 years ago when I first got my very first airband radio I heard a BMI flight from EDI - LHR that was going to be coming into contact somewhere along the way with a very similar flight number say for example Midland 990 and Midland 997 and to avoid confusion the flight out of EDI had to use the registration as the callsign.
 
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zeke
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RE: Reason For "Kilo" Being Appended To UA Callsign?

Tue Dec 14, 2010 3:06 pm

Quoting LAXintl (Reply 4):
From United's FOM:

And for a second I thought they were going metric     
We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
 
rduoodl
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RE: Reason For "Kilo" Being Appended To UA Callsign?

Wed Dec 15, 2010 2:35 am

Quoting Brick (Reply 9):
Why did we get a suffix added to our callsign?

To keep the original callsign for the flight across the pond.
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Mir
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RE: Reason For "Kilo" Being Appended To UA Callsign?

Wed Dec 15, 2010 3:48 am

Quoting PWMRamper (Reply 11):
How does it work with 4 digit flights numbers, ala RJs?

You can't have GJS 7358K, too many characters?

The flight number gets shortened somehow. Probably to GJS358K or GJS58K.

But regional carriers don't normally have two-leg flights operated by different aircraft, so this wouldn't be something you'd have to figure out on the fly. I know that some carriers fly for a couple of majors, and have the same flight number on two or more of those majors (i.e. Skywest flying both DL5280 and UA5280 - just making those up). Obviously, using the flight number doesn't work for that, so an alternative has to be worked out. But that's not hard at all if you know about it in advance.

-Mir
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AAR90
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RE: Reason For "Kilo" Being Appended To UA Callsign?

Wed Dec 15, 2010 5:16 am

Quoting PWMRamper (Reply 11):
How does it work with 4 digit flights numbers, ala RJs?

Can't speak for other airlines, but at AA the following applies....

Stub Originations.
1. One, two or three digit flight numbers will be amended by adding an alpha character. Flight schedules require that four
digit flight numbers be used. Due to character limits in the ATC filing format, the first digit of a four digit flight number must be dropped when adding an alpha character; thus, flight numbers will be adjusted as follows.


Base Flt. No. 123 : 1234 : 2615
. . .1st Stub. 123P : 234Q : 615R
. . 2nd Stub. 123T : 234U : 615V

2. A flight will be assigned a stub number if there is a possibility that two flights with the same flight number will be operating simultaneously in a given FAA Center Airspace.
a) A flight will be assigned a stub number when a flight is originating at a station other than scheduled origination.
3. The flight plan and the TPS/Departure plan may be obtained by using either the base flight number or the stub number. ACARS will not accommodate alpha - numeric inputs, thus, base flight numbers will always be used. The stub number and alpha characters will be used during all air to ground voice communications.
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WestWing
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RE: Reason For "Kilo" Being Appended To UA Callsign?

Wed Dec 15, 2010 5:22 am

Quoting LAXintl (Reply 4):
an alpha suffix (i.e., A, C, J, K, L, T, W or Y)

Ok, so the logical next question is why only these eight letters? Is this a FAA/ATC defined subset or is it a Company defined subset? I realize that some letters (e.g, D/Delta, M/Mike) might be potentially confusing over the air because of the conflict with operator callsigns - (for DL, CS) and so should be avoided.
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pilotpip
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RE: Reason For "Kilo" Being Appended To UA Callsign?

Wed Dec 15, 2010 5:31 am

Quoting PWMRamper (Reply 11):
How does it work with 4 digit flights numbers, ala RJs?

You can't have GJS 7358K, too many characters?

We've had a lot of problems with similiar call signs recently so we started going to the aircraft number on some flights. I don't know which is worse, myself or ATC trying to say "Mercury 639" over saying the 5900 (delta) and high 7000 numbers (united) I've been saying for the last 4 years.

Saying three digits seems so dirty...  
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