From A to G: A Guide to Understanding and Operating in Different Airspace Classes

When we study to become a drone pilot, one of the subjects is to understand and identify the type of airspace in which we are going to fly. Many times we find it difficult to understand how airspace is structured and classified, as drone pilots hardly see the differences between them. However, the drone industry is completely changing and has prepared regulations to allow UAS flights within the airspace occupied by manned aircraft in the future.

Therefore, the purpose of this article is to recover and explain those differences in the classification of airspace, both for pilots who want to refresh their knowledge, for those who are studying it now, and, of course, to start preparing for the future that we will see in the coming years.

Difference between VFR and IFR

First of all, we must differentiate and understand what VFR and IFR mean. Depending on the type of flight being performed, different rules will be applied.

If the flight is carried out following the visual flight rules, we will be flying under VFR (Visual Flight Rules), whereas if we fly according to the instrumental flight rules, we will be flying under IFR (Instrumental Flight Rules).

VFR

VFR consists of flying without the use of flight instruments, that is, looking out the window and following references on the ground to go from one point to another. In order to fly VFR, visibility is required (there are minimums covered in the regulations) and being in airspace that allows it.

IFR

IFR consists of flying using the aircraft’s flight instruments. In this case, the pilot will navigate from point A to point B following the indications of the cockpit instruments without using the visual references of VFR. Imagine a flight within the clouds without visibility or in the middle of the sea without references. The only way to navigate is through the use of instruments.

And in which category are drones?

For drones, there is no established classification, but according to a hierarchy and difficulty system, for now, drone operators would fall under the umbrella of VFR. It should be noted that all manned aircraft pilots start flying only under VFR, and only when they want to advance in their professional career, they become qualified to fly under IFR.

Controlled airspace and uncontrolled airspace

Airspace is divided into controlled or uncontrolled. The difference is quite simple: in controlled airspace, any action that is to be performed must be communicated to an air traffic controller for evaluation, and the controller’s instructions must always be followed.

On the contrary, uncontrolled airspace is one in which it is not necessary to wait for confirmation from an air traffic controller. Although flights may appear to be more free, it must be taken into account that pilots are responsible for managing their flight and do not have the “control” and security provided by Air Traffic Control.

Classification of airspace

Airspace is classified with letters depending on whether it is controlled or uncontrolled and how restrictive it may be. Therefore, for controlled airspace, we find airspace classes A, B, C, D, and E, and for uncontrolled airspace, we have classes F and G. Let’s see the most important differences between each of them:

Class A Airspace

Subject to ATC authorisation
All flights that are conducted are separated from each other to avoid collisions and organise air traffic in the area.
- It is the most restrictive of all and only allows IFR flights.

Class B Airspace

Allows both IFR and VFR flights.
Subject to ATC authorisation
All flights are separated from each other to avoid collisions and organise air traffic in the area.

Class C Airspace

Both VFR and IFR flights are allowed.
Subject to ATC authorisation
In this case, IFR flights are provided with separation service from other IFR flights and from VFR flights
VFR flights are only separated from IFR flights and are provided with information about other VFR flights.

Class D Airspace

Both VFR and IFR flights are allowed.
Subject to ATC authorisation
In this case, IFR flights are separated.
VFR flights only receive information about other IFR and VFR flights and do not have separation.

Class E Airspace

It is the least restrictive controlled airspace.
Both VFR and IFR flights are allowed.
Subject to ATC authorisation only for IFR flights
Only IFR flights receive traffic separation service from other IFR flights. It is shared responsibility for IFR flights to separate from VFR traffic.
VFR flights do not receive separation service.
Both IFR and VFR flights receive traffic information as much as possible.

Class F Airspace

No ATC authorisation is required.
Both IFR and VFR flights are allowed.
IFR flights receive separation information to ensure separation between IFR aircraft whenever possible.
VFR flights only have flight information service.

Class G Airspace

No ATC authorisation is required.
Both IFR and VFR flights are allowed.
Both IFR and VFR flights only have flight information service.

In other articles, we will study the different types of controlled and uncontrolled areas that we can find in both controlled and uncontrolled airspace. Among them, we find:

FIR and UIR (Flight Information Region and Upper Information Region)
TMA (Terminal Manoeuvring Area)
CTR (Controlled Traffic Region)
ATZ (Aerodrome Traffic Zone)