Annex 11 — Air Traffic Services
184.108.40.206.1.1 Those portions of controlled airspace wherein it is determined that air traffic control service will also be provided to VFR flights shall be designated as Classes B, C, or D airspace.
2.6.3 The requirements for flights within each class of airspace shall be as shown in the table in Appendix 4. Note.— Where the ATS airspaces adjoin vertically, i.e. one above the other, flights at a common level would comply with requirements of, and be given services applicable to, the less restrictive class of airspace. In applying these criteria, Class B airspace is therefore considered less restrictive than Class A airspace; Class C airspace less restrictive than Class B airspace, etc.
220.127.116.11.2 Where designated within a flight information region, control areas and control zones shall form part of that flight information region. 18.104.22.168 Controlled aerodromes. Those aerodromes where it is determined that air traffic control service will be provided to aerodrome traffic shall be designated as controlled aerodromes.
Classification of airspaces
Required navigation performance (RNP) for en-route operations
2.6.1 ATS airspaces shall be classified and designated in accordance with the following:
2.7.1 RNP types shall be prescribed by States. When applicable, the RNP type(s) for designated areas, tracks or ATS routes shall be prescribed on the basis of regional air navigation agreements.
Class A. IFR flights only are permitted, all flights are provided with air traffic control service and are separated from each other.
2.7.2 Recommendation.— For the en-route phase of flight, RNP types RNP 1, RNP 4, RNP 10, RNP 12.6 and RNP 20 should be implemented as soon as practicable.
Class B. IFR and VFR flights are permitted, all flights are provided with air traffic control service and are separated from each other.
2.7.3 The prescribed RNP type shall be appropriate to the level of communications, navigation and air traffic services provided in the airspace concerned.
Class C. IFR and VFR flights are permitted, all flights are provided with air traffic control service and IFR flights are separated from other IFR flights and from VFR flights. VFR flights are separated from IFR flights and receive traffic information in respect of other VFR flights.
Note.— Applicable RNP types and associated procedures are published in the Manual on Required Navigation Performance (RNP) (Doc 9613).
Class D. 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.
Establishment and designation of the units providing air traffic services
The air traffic services shall be provided by units established and designated as follows:
Class E. IFR and VFR flights are permitted, IFR flights are provided with air traffic control service and are separated from other IFR flights. All flights receive traffic information as far as is practical. Class E shall not be used for control zones.
2.8.1 Flight information centres shall be established to provide flight information service and alerting service within flight information regions, unless the responsibility of providing such services within a flight information region is assigned to an air traffic control unit having adequate facilities for the discharge of such responsibility.
Class F. IFR and VFR flights are permitted, all participating IFR flights receive an air traffic advisory service and all flights receive flight information service if requested.
Note.— This does not preclude delegating to other units the function of providing certain elements of the flight information service.
Note.— Where air traffic advisory service is implemented, this is considered normally as a temporary measure only until such time as it can be replaced by air traffic control. (See also PANS-ATM, Chapter 9.) Class G. IFR and VFR flights are permitted and receive flight information service if requested.
2.8.2 Air traffic control units shall be established to provide air traffic control service, flight information service and alerting service within control areas, control zones and at controlled aerodromes.
2.6.2 States shall select those airspace classes appropriate to their needs.
Note.— The services to be provided by various air traffic control units are indicated in 3.2. 2-3