Dual callsigns

[maredzki]

Hello, I noticed and started wondering why there are dual call signs. I’ve seen this for years but never heard an aircraft called by the secondary callsign until recently.

Here is an example: BA294/BAW20R. I’ve heard this one called by BAW20R instead of BA294.

Here is another one: LO3/LOT3E
What’s the purpose of that?

Thanks,
Marek

[obj]

One is the retail flight number (i.e. the flight number on the ticket that passengers see), one is the callsign actually used when filing / talking to ATC / etc.

The retail flight number will use the operator’s IATA prefix while the callsign usually uses the ICAO prefix.

The main two cases where they differ futher are:

• irrops (e.g. rescheduled or heavily delayed flights)
• callsign disambiguation (especially in Europe) which tries to avoid having flights with similar callsigns in the air at the same time: Call sign similarity service (CSS) | EUROCONTROL

[maredzki]

Thank you for the explanation, and you did bring up a good point as those callsigns that I noticed are all European carriers. It didn’t matter if the flight originated in EU or US, they still had the new callsign. I’ve noticed that with LOT as they normally use low callsign numbers with intercontinental flights, i.e. LOT10, where now ATC is calling them by LOT1RK.

ATC is evolving