As I’ve studied on ATC service and airspace class by referring to ICAO Annex, I have some doubts on ATC service.
According to ICAO Annex 11, Class D airspace is defined as “IFR and VFR flights are permitted and all flights are provided with air traffic control service, IFR flights are separated from other IFR flights and receive traffic information in respect of VFR flights, VFR flights receive traffic information in respect of all other flights.”
When referring to other definition such as ATS service, It is divided into ATC service, flight information service and alerting service. And I think separation and traffic information service are included to ATC service of ATS service.
So, when I read the definition of Class D airspace that IFR and VFR aircraft are provided with ATC service, I think separation and traffic information service are also provided because these are the ATC service. However, as you guys know, although ATC service is provided to all VFR and IFR in controlled airspace, separation and traffic information are selectively applied depending on airspace class.
To sum up, I want to know what ATC service includes and whether traffic information and separation are one of ATC service or not.