Although it may seem like stating the obvious, airspace is everything that exists in the open air, or in other words, everything that exists between the earth’s surface (soil or water) and the limits of the atmosphere. This is the space that, with specific exceptions, is destined to the flight of aircraft of any type.
Air traffic is possibly one of humanity’s most and best-regulated and controlled activities.
In the context of each country, as well as at the supranational level, there are organisations that are responsible for legislating and ensuring safety in this space. At any time of the day, there are tens of thousands of aircraft flying, from private drones to large commercial aircraft. Even in the case of a private estate, a garden or a privately owned enclosure, airspace is public and, therefore, under the management of the corresponding national agency.
In the specific case of RPAS or model airplanes, circumstances may arise in which they fly in completely enclosed environments (pavilions or covered stadiums). In such cases, the national air safety agencies do not have powers to legislate or sanction, and responsibility falls on the owner of the premises. However, when dealing with an area that is not covered in its entirety, or one with a retractable roof, the competence rests with the corresponding official entity.
There are three types of airspace: controlled, non-controlled and special use airspace. The type of airspace is defined in each case depending on the movement of aircraft, the purpose of the operations being carried out and the required level of safety.
The International Civil Aviation Organisation, ICAO, classifies airspace into seven types, naming them with letters ranging from A to G.
Airspaces classed as A, B, C, D and E are controlled. This is defined as those in which aircraft are subject to air traffic control provided by control units (area control centres, approach controls and airport control towers). Flights vary in type on the basis of the different classifications, as follows:
Class A. Only instrumental flights (IFR) are permitted, the air traffic control service is provided to all flights, and all flights are separated from each other.
Class B. Instrumental (IFR) and visual (VFR) flights are permitted, the air traffic control service is provided to all flights, and all flights are separated from each other.
Class C. Both IFR and VFR flights are permitted, the air traffic control service is provided to all flights, and the IFR flights are separated from other IFR and VFR flights. The VFR flights are separated from the IFR flights and receive air traffic information about other VFR flights.
Class D. Both IFR and VFR flights are permitted, and the air traffic control service is provided to all flights. The IFR flights are separated from other IFR flights and receive air traffic information about VFR flights. The VFR flights receive air traffic information about all other flights.
Class E. Both IFR and VFR flights are permitted, the air traffic control service is provided to all IFR flights and they are separated from other IFR flights. All flights receive air traffic information, to the extent practicable. Class E should not be used in control areas (ICAO recommendation).
Classes F and G correspond to non-controlled air spaces and, according to current legislation in most countries, this is where RPAS can fly. In these cases, no ATC (air traffic control) authorisation is required.
Although it may seem a bit complicated, let’s keep in mind the fact that air traffic is possibly one of humanity’s most and best-regulated and controlled activities. The aim is always the same: to keep safety at the highest level.