Use of flight numbers on ATC calls

[Hal]

I've been monitoring ATC on the web lately and I've noticed that a few flights are not using their flight numbers in there calls to ATC. For example the flight number might be Speedbird 294 but the call to ATC is Speedbird Romeo 20. Skywest seems to do this a lot. Anyone know why this is done?

Hal

[cancidas]

the callsign of a flight does not necessarely need to be the flight number. callsigns can change for many reason, schedules are one of them... but there are other. the change can happen because of a conflict with another a/c in one country's airspace but have no factor to anothers. the flight's dispatcher will generally be the one to file the callsign with ATC originally. (or the pilot in most GA aircraft)

[threeholerglory]

so how did the "Slurpee Express" end up with the tag "Pakistani 711"? Is the ATC designator a function of their dispatchers? Because if it is, that's pretty hilarious if you ask me.

[cancidas]

Slurpee Express

who?

[hiss srq]

Bwahahahahahaahah Mike, you're not right and Matt's a little slow tonight.... Matt, he was insinuating that PIA's JFK flight is more of the Employee Shuttle Bus for 711 as PIA's inbound flight number is Pakastani 711 Heavy