I was just browsing Flightaware and I noticed that DL has flights 407 and 408 departing from JFK only seven minutes apart and actually today because of weather the flights departed three minutes apart. Both flights are on 763s and both are to western Europe.
I was surprised to see two flights with such similar call signs, equipment and routes departing so close together from the same airport; I would think it could cause confusion for ATC. Are there any airlines that avoid clumping similar flight numbers together to prevent confusion with the controllers/flight crews?


http://flightaware.com/live/flight/DAL408

http://flightaware.com/live/flight/DAL407

Quoting AviationAddict (Thread starter): I was surprised to see two flights with such similar call signs, equipment and routes departing so close together from the same airport; I would think it could cause confusion for ATC. Are there any airlines that avoid clumping similar flight numbers together to prevent confusion with the controllers/flight crews? http://flightaware.com/live/flight/DAL408 http://flightaware.com/live/flight/DAL407

I wouldn't call these two "similar callsigns". There's enough differentiation between the words "seven" and "eight" to keep the confusion to a minimum. Similar callsigns would be DAL407 and DAL447.

Some of the regionals use alpha-numeric callsigns for flights into a hub (i.e., SKW89D) due to possibility of similarities because of the limited number of flight numbers in their major carrier-assigned flight number range. Some major airlines also do this for stub-amended and broken through-flights.

[Edited 2014-07-28 18:00:55]

Quoting AviationAddict (Thread starter): I was just browsing Flightaware and I noticed that DL has flights 407 and 408 departing from JFK only seven minutes apart and actually today because of weather the flights departed three minutes apart. Both flights are on 763s and both are to western Europe. I was surprised to see two flights with such similar call signs, equipment and routes departing so close together from the same airport; I would think it could cause confusion for ATC. Are there any airlines that avoid clumping similar flight numbers together to prevent confusion with the controllers/flight crews?

For years, the airlines cooperated with each other on avoiding similar call signs scheduled at the same time. That went out the window quite awhile back.

Confusing for everyone, as controllers often inadvertently transpose numbers in similar sounding flights. Then we have to divine whether or not ATC actually meant us, so we ask for clarification. Half the time they don't realize they called us by the wrong number and act irritated.

I'm not bitching about controllers, who I have tremendous respect for. It's the system that allows similar call signs to exist.

UA 686 PDX-ORD at 10:40
AS 686 PDX-ORD at 10:40 aswell

I remember reading a story on here about how US and AA both had flight 1776 into PHL near the same time

Quoting AviationAddict (Thread starter): I was surprised to see two flights with such similar call signs, equipment and routes departing so close together from the same airport; I would think it could cause confusion for ATC.

407 and 408 aren't really a problem. 408 and 48 would be a problem (because they sound similar on the radio), and 408 and 804 would be a problem (potential transposition error), as would Delta 408 and American 408 (same flight number).

-Mir

As a controller, this has always been one of my biggest pet peeves. I notice it a lot with DL and US. Seems to be a lot of the Caribbean flights all have similar call signs. I'm sure there is some logic behind it, but from our standpoint it just adds greater risk for aircraft taking others clearances.

Once upon a time VS200 9HKG-SYD) and DJ200 (BNE-SYD) would arrive in SYD at around the same time, and of course at that time Virgin Australia was using the callsign 'Virgin' (this was well before the 'Velocity' days)... pretty sure it was for that reason the BNE-SYD-BNE flight numbers changed from 2xx to 9xx.

Quoting maverickTTT (Reply 1): There's enough differentiation between the words "seven" and "eight" to

Quoting Mir (Reply 4): 407 and 408 aren't really a problem. 408 and 48

Points taken; I was thinking more along the lines of the controllers watching their screens and seeing two DL 767s heading east on nearly identical flight paths and both with flight numbers that start with 40...could see where it might cause confusion if one was busy and JFK during the evening international departures is about as busy as it gets.

[Edited 2014-07-28 20:04:29]

Quoting AviationAddict (Reply 7): Points taken; I was thinking more along the lines of the controllers watching their screens and seeing two DL 767s heading east on nearly identical flight paths and both with flight numbers that start with 40...could see where it might cause confusion if one was busy and JFK during the evening international departures is about as busy as it gets.

Yeah, 407/408 wouldn't be a problem at all. When it is a problem is when two airlines share the same numbers (as referenced above, e.g. UAL670 and DAL670) or when numbers are similar enough to cause confusion (e.g. DAL1122 and DAL2211, but numbers that are just sequential are easily distinguished from one another.

It's more likely to happen with general aviation aircraft, in which case it might require the controller to use the full callsign every time with both aircraft (e.g. there could be two aircraft abbreviated to November-six-two-foxtrott, so they'd have to be referred to as November-seven-three-six-two-foxtrott and November-two-one-six-two-foxtrott). Controllers normally utilize the abbreviated version that after the initial call, so using the full tail number is cumbersome. Even if one is a Cessna and the other a Piper, they'd still need to use the full callsign to eliminate any possibility for confusion. That gets tricky and it's actually not all that uncommon.

If the controller is worried about the possibility of confusion in any case, they can use phraseology specified in the FAA's air traffic "bible" (Order JO 7110.65V), which in effect cautions all aircraft to be aware that similar sounding callsigns are on frequency, and then listing the two (or more) aircraft it pertains to. Even if there's only a remote possibility for confusion like in your sequential numbers scenario, there's absolutely no harm in the controller making those on frequency aware so that pilots can listen carefully for their callsign.

If it really does create the potential for problems, the controller will notify his/her supervisor on duty of the similar callsigns, and they will investigate. If it's a one-off occurrence, then no further action will likely be taken. If it has become a regular thing due to the release of a new schedule for example (which is not unusual), the supervisor will contact the airline(s) involved to correct the issue. More often than not, the issues are resolved within days, because if the callsigns really are similar, it is a definite safety issue that airlines also take seriously.

Hope that helps answer your question!

Some airlines assign different flight numbers for operational and ATC purposes than the flight number used for reservations and booking purposes. I expect part of the reason could be to avoid confusion with other similar flight numbers.

For example, one of KL's YYZ-AMS flights uses flight number KL692 for marketing/reservations purposes but it operates as KLM32.
http://flightaware.com/live/flight/KLM32

Quoting Viscount724 (Reply 9): Some airlines assign different flight numbers for operational and ATC purposes than the flight number used for reservations and booking purposes. I expect part of the reason could be to avoid confusion with other similar flight numbers.

Usually when I've noticed this, it's because that same number is being used twice in the system. Both BA and UA used to do it quite often, there they'd market the flight as BAW288, but it would operate as BAW288J. Since the same number can't operate in the system for two flights, they have to differentiate them. The other time I've seen this is from Great Lakes, for example -- they market with the UA codeshare flight number (e.g. GLA6128), but they'll fly as Lakes Air 128.

I'm not sure if I've ever paid enough attention to see how airlines market and operate to see if they change numbers entirely, like in your example from 692 --> 32. As I said in my previous post, I know that the FAA (or applicable agency elsewhere) will contact the airlines involved if there is some kind of numbering confusion or conflict, and it's almost always worked out within days. The details after that are unknown to me, but it could be that they continue marketing the flight under the conflicted number, but operate under the new number. I've never investigated enough to see the end rest of those conflicts, but it would be understandable since they wouldn't want to swap flight numbers on people with confirmed tickets, so it makes sense.

Quoting atcsundevil (Reply 10): Quoting Viscount724 (Reply 9): Some airlines assign different flight numbers for operational and ATC purposes than the flight number used for reservations and booking purposes. I expect part of the reason could be to avoid confusion with other similar flight numbers. Usually when I've noticed this, it's because that same number is being used twice in the system. Both BA and UA used to do it quite often, there they'd market the flight as BAW288, but it would operate as BAW288J. Since the same number can't operate in the system for two flights, they have to differentiate them.

That wouldn't be the case in the KL example as that flight from YYZ has been using the KLM32 flight number quite a while and there wouldn't be two flights with the KLM692 number in the air simultaneously, unless there was a very long delay and the flight didn't leave until the following day when the regular flight for that day was also operating and in the air at the same time. They they would of course have to change the operating number to avoid duplication.

My guess is that with so many KL flights having fairly similar flight numbers and some probably taking almost the same route across the Atlantic at similar times, and several probably approaching AMS at about the same time, an ATC agency may have asked them to change a few of the operating flight numbers to avoid potential ATC confusion.

For example, KL marketing flight numbers eastbound from North America to AMS are as follows (may have missed one or two) and most if not all of those flights will probably be in the air simultaneously:

602 - LAX
604 - LAX
606 - SFO
612 - ORD
622 - ATL
640- JFK
642 - JFK
644 - JFK
652 - IAD
662 - IAH
670 - DFW
672 -YUL
678 - YYC
682 - YVR
686 - MEX
692 - YYZ
696 - YYZ

Quoting atcsundevil (Reply 10): I'm not sure if I've ever paid enough attention to see how airlines market and operate to see if they change numbers entirely

Lufthansa is one of the carriers that has the most flights operating under a call sign that is not the flight number. Most of their intra-European flights don't use the flight number at all. For example Lufthansa 7PL instead of 902 (FRA-LHR), 3H for 925 (LHR-FRA) or 5CT instead of 988 (FRA-AMS).
British Airways does it too, across the entire fleet unlike Lufthansa, but not as frequently. For example, flight 208 from MIA is Speedbird 34N.

[Edited 2014-07-31 01:11:15]

BA also has a separate call sign for their domestic flights “Shuttle” is still used with the number being the to / from destination.