blueflyer
Topic Author
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Letters In Call Signs

Sat Sep 15, 2012 4:52 am

I think I know (most of the time) why airlines use letters in their call signs when talking to ATC. What I am wondering is whether there is any logic in the "translation" between flight numbers and call signs. I know some British charter carriers use two letters, one each for inbound and outbound flights, but other carriers seem totally random.

For example, why does TAY161 become Quality 61 Golf instead of Quality 16 Golf, or Quality 61 Lima or another other option? I can't equally find any logic for Speedbird or Lufthansa, among others. Is there any or is it random?
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wilco737
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RE: Letters In Call Signs

Sat Sep 15, 2012 6:07 am

Quoting blueflyer (Thread starter):

On LH short haul flights the numbers and letters are random. So you cannot see which flight number it actually is.
The callsigns remain the same everyday. So with some research you can find out which flight it is.

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CosmicCruiser
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RE: Letters In Call Signs

Sat Sep 15, 2012 6:55 am

We sometimes must add a letter to a flight number if there's the same flight no. operating anywhere else at the same 24hr period.
 
skyhawkmatthew
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RE: Letters In Call Signs

Sat Sep 15, 2012 8:54 am

QantasLink and Virgin Australia append letters to identify aircraft with vastly different performance.

The A in 'Virgin 123 Alpha' is appended to identify an ATR, which is obviously much slower than the rest of the Virgin (jet) fleet. Equally, QantasLink appends a D, as in 'Qlink 123 Delta' to identify Q400s (ICAO DH8D), which have much better performance than the other Dash 8 series aircraft.
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Fabo
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RE: Letters In Call Signs

Sat Sep 15, 2012 9:24 am

Aside from identifying characters as in Virgin Australia and Qantaslink examples, most of the airlines changed to alphanumerics because it was too common to mistake your callsign to a similar callsign of your own, or even other carrier.

For example, if there was a Speedbird 602 inbound and Speedcat 602 outbound, or if you flew Airline 952 and there was another Airline 592 flight... Airlines moved do alphanumerics so that there is less chance of confusion. Some tried to use alphanumerics based on destination, but of course then you ended with all flights of non-based carriers being, for example, nBP (EZY2BP, AUA3BP, AFR4BP) on frequency in Budapest, so these combinations must be random. Some airlines will then alter them if a similar callsign is reported to be met on frequency regularly.
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blueflyer
Topic Author
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RE: Letters In Call Signs

Sun Sep 16, 2012 9:21 pm

So sometimes it is random, sometimes not, very interesting.

Quoting skyhawkmatthew (Reply 3):
QantasLink and Virgin Australia append letters to identify aircraft with vastly different performance.

I'm guessing ATC has been made aware of the reason behind the use of the letters then?
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skyhawkmatthew
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RE: Letters In Call Signs

Mon Sep 17, 2012 2:55 am

Quoting blueflyer (Reply 5):
I'm guessing ATC has been made aware of the reason behind the use of the letters then?

I expect ATC sequencing is the whole reason behind the use of the letters: they're not used in any public-facing communication.
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AJ
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RE: Letters In Call Signs

Mon Sep 17, 2012 3:32 am

Quoting skyhawkmatthew (Reply 3):
Equally, QantasLink appends a D, as in 'Qlink 123 Delta' to identify Q400s (ICAO DH8D), which have much better performance than the other Dash 8 series aircraft.

Additionally, Qantas (mainline) uses a D for a delayed service, as it is quite possible to have two flights airborne with the same flight number otherwise.
 
Goldenshield
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RE: Letters In Call Signs

Mon Sep 17, 2012 11:11 am

Quoting skyhawkmatthew (Reply 6):
Quoting blueflyer (Reply 5):
I'm guessing ATC has been made aware of the reason behind the use of the letters then?

I expect ATC sequencing is the whole reason behind the use of the letters: they're not used in any public-facing communication.

Seems a bit redundant to me. The aircraft type is already part of the flight plan.
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skyhawkmatthew
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RE: Letters In Call Signs

Mon Sep 17, 2012 11:29 am

Quoting Goldenshield (Reply 8):
Seems a bit redundant to me. The aircraft type is already part of the flight plan.

Yes, but if you're busy dealing with large amounts of traffic (and a lot of 'Qlink' aircraft about: QantasLink makes up around 40% of Qantas group flights), it's a more obvious cue that that aircraft is much faster than the rest. IIRC the Q400 is in a heavier wake turbulence class as well.
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Goldenshield
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RE: Letters In Call Signs

Mon Sep 17, 2012 12:52 pm

Quoting skyhawkmatthew (Reply 9):

Yes, but if you're busy dealing with large amounts of traffic (and a lot of 'Qlink' aircraft about: QantasLink makes up around 40% of Qantas group flights), it's a more obvious cue that that aircraft is much faster than the rest. IIRC the Q400 is in a heavier wake turbulence class as well.

In the enroute portion, I guess it'd make sense, but in the terminal environment, it's not going to be as obvious; everyone's going the same speeds. (At least, here in the States they are. I don't know about Oz.)

I'll go ask Los Angeles Center how they feel about something like this.  
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Viscount724
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RE: Letters In Call Signs

Mon Sep 17, 2012 10:48 pm

KLM has 2 daily flights AMS-YYZ. They're booked as KL691 and KL695. For operational purposes KL691 uses the callsign KLM31. The other flight retains its actual flight number and operates as KLM695.
 
fxra
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RE: Letters In Call Signs

Tue Sep 18, 2012 4:53 am

Back a while back, FDX used to use a lot of letters on int'l flights for traffic rights and regauging of aircraft. FOr example (I'm pulling these numbers out of the air) There used to be a FX19 that was IND-ANC-NRT on say an MD-11, then an A300 would operate 19K NRT-ICN and and noather airbus would operate 19M NRT-HKG. I asked once why the letters and was told that often is was due to traffic rigths requirements.
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