What the letter tells you
ICAO defines seven airspace classes, A to G. In the EU, the classes and their rules are set by the Standardised European Rules of the Air (SERA, Regulation (EU) No 923/2012): SERA.6001 defines the classes, and SERA.5001 sets the VFR visibility and distance-from-cloud minima.
Classes A to E are controlled airspace; F and G are uncontrolled. Each state chooses which classes it uses and where. The same letter carries the same baseline SERA rules in every SERA state, subject to national options published in the AIP, but the same kind of structure, a TMA for example, can be class C in one country and class D or E in the next.
The classes at a glance
The table summarises SERA.6001 from a VFR pilot's point of view.
| Class | Flights | Separation and service | VFR clearance | VFR radio | 250 kt IAS below 10 000 ft AMSL |
|---|---|---|---|---|---|
| A | IFR only | All flights receive ATC service and are separated from each other. | VFR not permitted | Not applicable | Not applicable |
| B | IFR and VFR | All flights receive ATC service and are separated from each other. | Required | Continuous two-way | No |
| C | IFR and VFR | IFR is separated from IFR and VFR. VFR is separated from IFR and gets traffic information on other VFR, with avoidance advice on request. | Required | Continuous two-way | VFR flights |
| D | IFR and VFR | IFR is separated from IFR. VFR is not separated but gets traffic information on all other flights, with avoidance advice on request. | Required | Continuous two-way | All flights |
| E | IFR and VFR | IFR receives ATC service and is separated from IFR. All flights get traffic information as far as practical. | Not required | Not required by the class | All flights |
| F | IFR and VFR | Participating IFR gets an air traffic advisory service; all flights get flight information service on request. | Not required | Not required by the class | All flights |
| G | IFR and VFR | Flight information service on request. | Not required | Not required by the class | All flights |
The competent authority can waive the 250 kt limit for aircraft types that cannot keep to it for technical or safety reasons. SERA treats class F as a temporary measure until it can be replaced by another classification, and it does not allow class E for control zones. An RMZ or TMZ can add radio or transponder requirements in any class where the table says "not required"; see TMZ and RMZ explained.
What changes for VFR pilots, class by class
In practice, a VFR pilot meets the classes like this:
- Class A: closed to VFR flights.
- Class B: rarely used in Europe. Where it exists, VFR flights are cleared and separated from all other traffic.
- Class C: clearance and two-way radio required. ATC separates you from IFR traffic and gives traffic information on other VFR flights. SERA classifies all airspace above FL195 as class C.
- Class D: clearance and two-way radio required. ATC does not separate VFR flights but gives traffic information on all other flights. Many European control zones (CTRs) are class D.
- Class E: no clearance and no radio required for VFR by the class itself, while IFR flights are controlled around you. Watch for RMZ and TMZ overlays.
- Class F: uncontrolled, with an advisory service for participating IFR flights. Few European states still use it.
- Class G: uncontrolled; flight information service is available on request.
SERA VMC minima
SERA.5001 sets the minimum flight visibility and distance from cloud for VFR flight. The bands depend on altitude as well as class:
| Altitude band | Classes | Flight visibility | Distance from cloud |
|---|---|---|---|
| At and above 10 000 ft AMSL (3 050 m) | A*, B, C, D, E, F, G | 8 km | 1 500 m horizontally; 1 000 ft (300 m) vertically |
| Below 10 000 ft AMSL and above 3 000 ft AMSL (900 m) or 1 000 ft (300 m) above terrain, whichever is higher | A*, B, C, D, E, F, G | 5 km | 1 500 m horizontally; 1 000 ft (300 m) vertically |
| At and below 3 000 ft AMSL or 1 000 ft above terrain, whichever is higher | A*, B, C, D, E | 5 km | 1 500 m horizontally; 1 000 ft (300 m) vertically |
| At and below 3 000 ft AMSL or 1 000 ft above terrain, whichever is higher | F, G | 5 km** | Clear of cloud and with the surface in sight |
* Class A minima are guidance for pilots only; they do not mean VFR flights are accepted in class A. Where the transition altitude is lower than 10 000 ft AMSL, FL100 is used instead of 10 000 ft.
** When the competent authority prescribes it, flight visibility may be reduced to not less than 1 500 m for flights at 140 kt IAS or less, or where encounters with other traffic are normally unlikely, such as low-level aerial work in low-traffic areas. Helicopters may be permitted down to 800 m if flown at a speed that gives adequate opportunity to see and avoid other traffic and obstacles.
These are the SERA minima. Night VFR, special VFR in control zones and national additions have their own rules; check the state's AIP, section ENR 1.2.
States differ: check the AIP
SERA lets each state designate the classes that suit its airspace, as long as airspace above FL195 is class C. The result is a patchwork: many states use no class B at all, class F has largely disappeared, and a terminal area can be class C, D or E depending on the country.
Two sections of each national AIP settle it: ENR 1.4 for the airspace classification and ENR 1.2 for the visual flight rules. The chart and the live map show the class of each volume; the AIP gives the national additions. Start from the FIR pages for the national AIS of each country, and see TMA and ATZ for structures you will meet in several classes.
Worked example: a VFR climb out of class G
Illustrative scenario: a VFR pilot departs an uncontrolled airfield in class G, climbs into class E and then routes into a class D control zone at a neighbouring airport. The airspace layout is generic, not a real location.
- Class G, below 3 000 ft AMSL: 5 km flight visibility, clear of cloud and with the surface in sight. No clearance; flight information service on request.
- Class E, above 3 000 ft AMSL: 5 km visibility and 1 500 m horizontally and 1 000 ft vertically from cloud. Still no clearance for VFR, but IFR traffic is under control around you. An RMZ or TMZ on the chart would add a radio call or a transponder requirement.
- Before the class D CTR boundary: call the tower, obtain a clearance and keep a continuous listening watch. Below 3 000 ft AMSL the class D minima remain 5 km and 1 500 m / 1 000 ft from cloud; the class G "clear of cloud" rule does not apply there.
- Throughout, below 10 000 ft AMSL: no more than 250 kt IAS.
Before your next flight
Turn the class rules into a plan:
- Trace your route on the live map and note each class change, including the vertical ones.
- Check for RMZ and TMZ overlays and plan your calls; see TMZ and RMZ explained.
- Run a route briefing: NOTAMs can activate part-time CTRs and temporary restricted areas that change the picture.
- Look up any unfamiliar term in the NOTAM and airspace glossary.