Airspace classes A to G
Free lesson · Air Regulations · DGCA CPL and ATPL
Seven letters of airspace. What each one gives you, and the air traffic services behind them.
What is ATS for, and who does each job?
5 jobs, 3 services
Five objectives (a to e) are split between three services. Tap a box with + to see the parts.
- Air Traffic Services 5 objectives, 3 services ATS has five objectives (a to e), met by three services: air traffic control (a, b, c), flight information (d) and alerting (e).
- Air Traffic Control objectives a, b, c The service that accomplishes objectives a, b and c. It is divided into area, approach and aerodrome control.
- a. Prevent collisions between aircraft The first job of ATC.
- b. Prevent collisions on the manoeuvring area With other aircraft and obstructions on the ground. Only aerodrome control covers this.
- c. Expedite and keep an orderly flow Keep traffic moving efficiently.
- Three units area, approach, aerodrome ATC is split into area, approach and aerodrome control, each handling a different part of a controlled flight.
- Area control a, c ATC for controlled flights, except the parts handled by approach and aerodrome control. It achieves objectives a and c and is provided by an area control centre.
- Approach control a, c ATC for the arrival and departure parts of controlled flights. It achieves objectives a and c.
- Aerodrome control a, b, c The only unit that also covers objective b.
- Flight Information Service objective d The service that accomplishes objective d. It goes to all aircraft likely to be affected that receive ATC or are otherwise known to the ATS units.
- d. Advice and information for safe, efficient flight Includes SIGMET, volcanic and radioactive cloud, navigation aid and aerodrome information.
- ATIS broadcast, max 30 seconds Each new message takes the next letter of the spelling alphabet. Not broadcast on an ILS voice channel.
- Alerting Service objective e The service that accomplishes objective e. It covers all aircraft with ATC, others on a flight plan or known to ATS as far as practicable, and any aircraft subject to unlawful interference.
- e. Notify search and rescue Tell SAR organisations about aircraft that need help, and assist them.
- Works in 3 phases INCERFA, ALERFA, DETRESFA When an aircraft gets into trouble, ATS tells the rescue coordination centre straight away. Emergencies come in three stages: uncertainty, alert and distress.
- Air Traffic Control objectives a, b, c The service that accomplishes objectives a, b and c. It is divided into area, approach and aerodrome control.
Memory hook: CIA: Control, Inform, Alert.
Takeaway: Collisions and traffic flow belong to ATC. Advice belongs to FIS. Calling SAR belongs to Alerting.
How much protection does each airspace class give?
Classes A to G
Each step down the alphabet removes protection. * A and B are under consideration in India.
| Class | Who may fly | Who is separated | Service | Clearance needed | 250 kt below 10,000 ft | Radio |
|---|---|---|---|---|---|---|
| A* | IFR only | Everyone from everyone | ATC | Yes | Not applicable | All |
| B* | IFR and VFR | Everyone from everyone | ATC | Yes | Not applicable | All |
| C | IFR and VFR | IFR from all; VFR from IFR | ATC | Yes | VFR only | All |
| D | IFR and VFR | IFR from IFR | ATC + traffic info | Yes | All | All |
| E | IFR and VFR | IFR from IFR | ATC for IFR | IFR only | All | IFR |
| F | IFR and VFR | IFR kept apart from IFR where possible | Advisory | No | All | IFR |
| G | IFR and VFR | Nobody | Information only | No | All | IFR |
Memory hook: A to G is a ladder going down: less control on every rung.
Takeaway: A and B separate everyone. C separates VFR from IFR. D and E separate IFR from IFR only. F is advisory. G is information only.