Air Traffic Service Units: Call Signs

Think of air traffic services units and most people will think exclusively of “Air Traffic Control“.  However, not all airspace is “controlled”, but you can still have radio communications with an air traffic service and in many cases the communication will sound not dissimilar to what a typical person would assume to be ‘Air Traffic Control’ (e.g. Class F airspace)……..Call signs are what differentiates the type of service you’re talking to.

Air Traffic Control Unit (ATCU): “Control”, “Radar”, “Approach”, “Director”, “Tower”, “Ground”

Aerodrome Flight Information Service (AFIS): “Information”

Aerodrome Air/Ground Communication Service (AGCS): “Radio”

Without going into detail a Control Unit has the highest qualified employees and you’ll be dealing with professional controllers who’ve passed a set of CAA exams, an ATCU is the only service which can provide a Clearance (A Permission or Instruction to act).   ‘Information’ will have you talking to someone who’s passed a few less exams and likely have less equipment, as such they can only provide ‘information’.    Finally AGCS means you’re talking to someone who has a ‘certificate of competence’, AGCS can only give information with regard to the aerodrome itself and any traffic they know about.

If ATCU’s are the only people who can tell you to do something:

  • All other actions taken are the responsibility of the Pilot In Command (PIC)
  • It’s really important to know who you’re talking to!

Because Callsigns are the only means of telling who you’re talking to:

It is an offense to use an inappropriate Callsign.

As such, if an AGCS started declaring itself to be “Tower” or “Control” (instead of “Radio”).  They would be fast tracking themselves to having their licence removed and potentially other legal actions taken against them.

It’s worth a reminder here that there is a difference between the types of “Air Traffic Services” and the types of “Air Traffic Service Units” described above.

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