Airspace Classes (A–G, CTR, TMA, RMZ, TMZ)

Airspace is divided into classes from A to G, each with specific rules regarding communication, separation, visibility, and services provided. These classifications are defined by ICAO (International Civil Aviation Organization), but implementation details may vary slightly from country to country.

Controlled airspace includes Classes A to E. Class F is rarely used, and Class G is uncontrolled. In addition, certain airspace types like CTRs, TMAs, RMZs, and TMZs are layered over these classes to define specific operational environments near airports or sensitive areas.

• Only IFR flights are permitted.
• Full ATC separation is provided for all aircraft.
• Continuous two-way communication and ATC clearance required.
• Not used for VFR flights under any circumstances.

• Allows both IFR and VFR.
• All aircraft receive ATC separation.
• Requires clearance and continuous radio contact.
• Typically used around major international airports (e.g., USA).

• Both IFR and VFR allowed.
• IFR receives separation from all aircraft; VFR gets separation from IFR and traffic information on other VFR.
• Radio contact and clearance required for both.

• Both IFR and VFR allowed.
• IFR separated from IFR; VFR receives traffic information only.
• ATC clearance and two-way communication required.
• Common in CTRs (Control Zones) around regional airports.

• IFR and VFR permitted.
• IFR gets separation; VFR not separated and no clearance required.
• Radio contact not required for VFR in some countries, but highly recommended.
• Often starts at 1,000 or 2,500 ft AGL depending on region.

• Advisory airspace (rare in Europe).
• Limited ATC service.
• Not widely used or relevant for most general aviation operations.

• Uncontrolled airspace.
• Both IFR and VFR allowed, but no ATC separation provided.
• Radio use not mandatory unless in designated RMZ/TMZ.
• Pilots are responsible for their own separation.

A defined volume of controlled airspace around an airport, extending from the surface to a specified upper limit.

• Usually Class D in Europe.
• Requires ATC clearance before entry.
• Used to protect arriving and departing traffic.

A larger volume of controlled airspace above one or more CTRs.

• Designed for handling arriving and departing IFR flights.
• Usually Class C or D.
• Often layered in complex configurations.

Airspace where radio communication is mandatory for all flights, even though it may be Class G.

• Designed to increase situational awareness and traffic coordination.
• No ATC clearance required, but pilots must make position and intention calls.

All aircraft must operate a functioning transponder (usually Mode S).

• No ATC clearance required unless within controlled airspace.
• Often overlaps with RMZs or busy Class G corridors.

• VFR pilots must be aware of the airspace class they are operating in and comply with the respective requirements.
• Entering controlled airspace (A–D) without clearance is a violation and may lead to enforcement actions.
• Airspace classes are depicted on aeronautical charts and should be reviewed thoroughly during flight planning.