Why do some airlines use alphanumeric callsigns in the flightplan when the flight number printed on the ticket consists of only numbers?

For example, the flight TK871 uses callsign THY4JT.


1 Answer 1


when flight delays cause a duplication of a flight number- there is a suffix added. For example- flight 1423 DFW/OKC is also operating as OKC to DFW. Normally a turn of equipment- however, DFW/OKC delayed significantly- equipment and crew is available to operate 1423 OKC/DFW. These 2 could be in route simultaneously- one is usually designated as a suffix- 1423J Call sign American 1 4 2 3 Juliette

  • 2
    $\begingroup$ Welcome to Aviation.SE! Please read the help center to see what makes a good question / answer. Also have a read of other answers on questions for examples of what makes a good answer. Generally well formatted answers with references do best. $\endgroup$
    – Notts90
    Aug 2, 2017 at 20:08
  • $\begingroup$ The question is regarding completely changing the number from 871 to 4JT, not just adding a letter at the end. $\endgroup$
    – fooot
    Aug 2, 2017 at 22:22

Not the answer you're looking for? Browse other questions tagged .