Classification of Airspace

Description

ATS airspace is classified and designated in accordance with the following:

Class A. IFR flights only are permitted, all flights are provided with air traffic control service and are separated from each other.

Class B. IFR and VFR flights are permitted, all flights are provided with air traffic control service and are separated from each other.

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.

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.

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.

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.

Class G. IFR and VFR flights are permitted and receive flight information service if requested.

(ICAO Annex 11: Air Traffic Services, Chapter 2, Section 2.6)

The services provided and flight requirements for different classes of airspace are shown in the table below.

 

ClassType of flightSeparation ProvidedService ProvidedSpeed limitation*Radio communication requirementSubject to an ATC clearance
AIFR onlyAll aircraftAir traffic control serviceNot applicableContinuous two-wayYes
BIFRAll aircraftAir traffic control serviceNot applicableContinuous two-wayYes
VFRAll aircraftAir traffic control serviceNot applicableContinuous two-wayYes
CIFRIFR from IFR

IFR from VFR

Air traffic control serviceNot applicableContinuous two-wayYes
VFRVFR from IFR1) Air traffic control service for separation from IFR

2) VFR/VFR traffic information service (and traffic avoidance advice on request)

250 kts IAS below 10000 ft amslContinuous two-wayYes
D (1)IFRIFR from IFRAir traffic control service, traffic information about VFR flights (and traffic avoidance advice on request)250 kts IAS below 10000 ft amslContinuous two-wayYes
VFRNilIFR/VFR and VFR/VFR traffic information (and traffic avoidance advice on request)250 kts IAS below 10000 ft amslContinuous two-wayYes
E (2)IFRIFR from IFRAir traffic control service and, as far as practical traffic information about VFR flights250 kts IAS below 10000 ft amslContinuous two-wayYes
VFRNilTraffic information as far as practical250 kts IAS below 10000 ft amslNoNo
FIFRIFR from IFR as far as practicalAir traffic advisory service; flight information service250 kts IAS below 10000 ft amslContinuous two-wayNo
VFRNilFlight information service250 kts IAS below 10000 ft amslNoNo
GIFRNilFlight information service250 kts IAS below 10000 ft amslContinuous two-wayNo
VFRNilFlight information service250 kts IAS below 10000 ft amslNoNo
* When the height of the transition altitude is lower than 10,000 ft amsl, FL100 should be used in lieu of 10000 ft

(ICAO Annex 11: Air Traffic Services, Chapter 2, Appendix 4)

Important Notes:

(1): In Class D airspace, both IFR and VFR traffic are required to follow ATC clearances; however, ATC are only responsible for IFR against IFR separation.

(2): In Class E airspace, ATC does not provide separation between IFR and VFR traffic; IFR traffic shares responsibility for separation from uncontrolled VFR traffic with that traffic.

Related Articles

Further Reading

ICAO Annex 11 Chapter 2 and Appendix 4

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