ENR 1.4  ATS AIRSPACE CLASSIFICATION

1.  Classification of airspaces

1.1  ATS airspaces are classified and designated in accordance with the following:

  • Class A. IFR flights are permitted only, all flights are subject to Air Traffic Control service and are separated from each other.

  • Class B. IFR and VFR flights are permitted, all flights are subject to Air Traffic Control service and are separated from each other.

  • Class C. IFR and VFR flights are permitted, all flights are subject to 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 infor mation in respect of other VFR flights.

  • Class D. IFR and VFR flights are permitted and all flights are subject to 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 informa tion in respect of all other flights.

  • Class E. IFR and VFR flights are permitted, IFR flights are subject to Air Traffic Control service and are separated from other IFR flights. ALL flights receive traffic information as far as practical.

  • 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 request.

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

1.2 Airspace classification is defined all ATS routes within Bangkok FIR are as follows:

  1. Class A from FL285 and above.

  2. Class B from Below FL285.

The requirements for the flights within each class of airspace are as shown in the table.

ATS AIRSPACE CLASSIFICATION

ClassType of flightSeparation providedService providedVMC visibility and distance from cloud minimaSpeed limitationRadio communication requirementSubject to an ATC clearance
A IFR onlyAll aircraftAir traffic control serviceNot applicableNot applicableContinuous two-wayYes
B IFR All aircraftAir traffic control serviceNot applicableNot applicableContinuous two-wayYes
VFR All aircraftAir traffic control service

8 km at and above 3 050 m (10 000 ft) AMSL

5 km below 3 050 m (10 000 ft) AMSL clear of clouds

Not applicableContinuous two-wayYes
C IFR

IFR from IFR

IFR from VFR

Air traffic control serviceNot applicableNot applicableContinuous two-wayYes
VFR

VFR from IFR

  1. Air traffic control ser vice for separation from IFR

  2. VFR traffic information (and traffic avoidance advice on request)

8 km at and above 3 050 m (10 000 ft) AMSL

5 km below 3 050 m (10 000 ft) AMSL

1 500 m horizontal; 300 m vertical distance from cloud

250 kt IAS Below 3050 m (10 000 ft) AMSLContinuous two-wayYes
D IFR IFR from IFRAir traffic control service including traffic information about VFR flight (and traffic avoidance device on request)Not applicable250 kt IAS below 3050 m (10 000 ft) AMSLContinuous two-wayYes
VFR Not providedTraffic informa tion between VFR and IFR flights (and traf fic avoidance advice on request)

8 km at and above 3 050 m(10 000 ft) AMSL

5 km below 3 050 m(10 000 ft) AMSL

1 500 m horizontal; 300 m vertical distance from cloud

250 kt IAS below 3050 m (10 000 ft) AMSL Continuous two-wayYes
E IFR IFR from IFRAir traffic control service and traf fic information about VFR flights as far as practicalNot applicable250 kt IAS below 3050 m (10 000 ft) AMSL Continuous two-wayYes
VFR Not providedTraffic informa tion as far as practical

8 km at and above 3 050 m(10 000 ft) AMSL

5 km below 3 050 m(10 000 ft) AMSL

1 500 m horizontal; 300 m vertical distance from cloud

250 kt IAS below 3050 m (10 000 ft) AMSL Not requiredNot required
F IFR IFR from IFR as far as practicalAir traffic advi sory service; flights informa tion serviceNot applicable250 kt IAS below 3050 m (10 000 ft) AMSLContinuous two-wayNot required
VFR Not providedFlight informa tion service

8 km at and above 3 050 m(10 000 ft) AMSL

5 km below 3 050 m(10 000 ft) AMSL

1 500 m horizontal; 300 m vertical distance from cloud

At and below 900 m AMSL or 300 m above terrain whichever is higher- 5 km* clear of cloud and in sight of ground of water

250 kt IAS below 3050 m (10 000 ft) AMSLNot required Not required
G IFR Not provided Flight informa tion service Not applicable 250 kt IAS below 3050 m (10 000 ft) AMSLContinuous two-wayNot required
VFR Not provided Flight informa tion service

8 km at and above 3 050 m(10 000 ft) AMSL

5 km below 3 050 m(10 000 ft) AMSL

1 500 m horizontal ; 300 m vertical distance from cloud

At and below 900 m AMSL or 300 m above terrain whichever is higher- 5 km* clear of cloud and in sight of ground of water

250 kt IAS below 3050 m (10 000 ft) AMSLNot required Not required

* When so prescribed by the appropriate ATS authority:

  1. lower flight visibilities to 1 500 m may be permitted for flights operating:

    1. at speeds that will give adequate opportunity to observe other traffic or any obstacles in time to avoid collision; or

    2. in circumstance in which the probability of encounters with other traffic would normally below e.g. in areas of low traffic volume an for aerial work at low levels;

  2. helicopters may be permitted to operate in less than 1 500 m flights visibility, if manoeuvred at the speed that will give adequate opportunity to observe other traffic or any obstacles in time to avoid collision.