ICAO Airspace Classification
Most countries are member of the International Civil Aviation Organization (ICAO) and as such have signed the "Chicago Convention 1944" (111 pages, 2 Mb). Aviation rules and regulations in member countries are based on the recommendations of the ICAO.
ICAO Annex 11: Air Traffic Services, Chapter 2, Section 2.6 describes the classifications of airspaces classes A - G and the services the pilot may expect from air traffic control. The table below shows this in a more comprehensible form.
Airspace Separation & Services
ICAO Airspace classes A - G are listed below:
| Class | Flight Rules | Separation | Service Provided | Speed Limit | Communication Required | ATC Clearance |
| A | IFR only | All Aircraft | Air Traffic Control | Not applicable | Two way | Yes |
|---|---|---|---|---|---|---|
| B | IFR | All Aircraft | Air Traffic Control | Not applicable | Two way | Yes |
| VFR | All Aircraft | Air Traffic Control | Not applicable | Two way | Yes | |
| C | IFR | IFR from IFR, IFR from VFR | Air Traffic Control | 250 kts below 10000ft | Two way | Yes |
| VFR | VFR from IFR | ATC and Traffic Information | 250 kts below 10000ft | Two way | Yes | |
| D | IFR | IFR from IFR | Air Traffic Control, Traffic Info about VFR flights | 250 kts below 10000ft | Two way | Yes |
| VFR | nil | IFR/VFR and VFR/VFR Traffic Information | 250 kts below 10000ft | Two way | Yes | |
| E | IFR | IFR from IFR | Air Traffic Control, Traffic Info as far as practicable about VFR flights | 250 kts below 10000ft | Two way | Yes |
| VFR | nil | Traffic Information as far as practicable | 250 kts below 10000ft | No | No | |
| F | IFR | IFR from IFR as far as practicable | Air Traffic Advisory, Flight Information Service | 250 kts below 10000ft | Two way | No |
| VFR | nil | Flight Information Service | 250 kts below 10000ft | No | No | |
| G | IFR | Nil | Flight Information Service | 250 kts below 10000ft | Two way | No |
| VFR | nil | Flight Information Service | 250 kts below 10000ft | No | No |
Based on: ICAO Annex 11: Air Traffic Services, Chapter 2, Section 2.6 and Appendix 4
Remember that each country can apply changes to the ICAO classification, be sure to read the AIP.
