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“SWISS calling” the call-sign challenge

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During the summer SWISS pilots are flying double-tracked, which poses a special challenge when operating flights for Edelweiss Air.

If you have ever wondered how pilots and air traffic controllers communicate, you might probably think “via radio, of course”. True, but how do pilots know that the controller is talking to their specific flight?

During the course of a normal flight in a passenger jet, air traffic controllers communicate vital information to the pilots, namely by assigning altitudes, clearances, directions, frequencies or traffic information.

The call sign of a flight is normally the commercial flight number, for example SWISS 632 for a flight from Zurich to Paris. Because flights operated by other airlines sometimes have very similar flight numbers, the flight numbers are altered according to the ICAO phonetic alphabet to avoid confusion. So flight 332 from Zurich to London becomes “SWISS 33J (for Juliet)”

During the summer and vacation time SWISS operates flights on behalf of Edelweiss Air, in addition to its own flights. For us pilots this presents is a very welcome chance to fly to such exotic airports as Mykonos, Rhodes, Santorini or Larnaca. As those flights operate under an Edelweiss flight number, the call sign begins with “Edelweiss” instead of “SWISS”.

During flights with these unfamiliar call signs it has become common for captains and co-pilots to engage in a small bet as to who will most often mix up the call sign by saying the more familiar “SWISS” instead of “Edelweiss” when communicating with air traffic control.

On my most recent Edelweiss flight to Palma de Mallorca I really tried hard to always say the correct call sign, but one time the flight became the “SWISS 1240” instead of “Edelweiss 1240”. The captain noticed my mistake at once and instantly said “Oh, you owe me one!” But the day was not over yet and I waited for the captain to make the same mistake, But after the second flight it became clear that he was doing a perfect job and not even once did he confuse the call signs.

Our planned night-stop was cancelled due to a schedule change, which saved me from having to pay for the captain’s drink. But I am eager to see if he remembers this the next time we fly together. Until then I am trying hard not to mix up the call signs so I won’t be in debt with every one of our captains. That could become expensive…