EASA Drone Glossary – Key Terms Explained

Operations

VLOS

Visual Line of Sight

VLOS means the remote pilot can see the drone with unaided vision (corrective lenses allowed) and maintain continuous awareness of its flight path and surroundings.

Operations

BVLOS

Beyond Visual Line of Sight

BVLOS operations take place when the remote pilot cannot maintain direct visual contact with the aircraft; they typically require specific-category authorisation, STS, or an operational authorisation.

Operations

EVLOS

Extended Visual Line of Sight

EVLOS extends VLOS using observers or technical means so the remote pilot team maintains situational awareness beyond the pilot's direct line of sight.

Operations

Remote pilot

The remote pilot is the person who directly controls the flight of the UAS or supervises an autonomous flight.

Operations

Operator

The UAS operator is the legal entity or person responsible for the operation — registration, insurance, manuals, and compliance — which may differ from the remote pilot.

Operations

UAS

Unmanned Aircraft System

A UAS includes the unmanned aircraft, remote control station, links, and any other equipment required to operate safely.

Operations

UA

Unmanned Aircraft

The UA is the flying device itself — the drone airframe and its installed systems — without the ground control components.

Operations

UAV

Unmanned Aerial Vehicle

UAV is a common synonym for unmanned aircraft; in EASA rules the preferred term is UA within a UAS.

Operations

Payload

Payload is any equipment carried by the drone that is not required for flight, such as cameras or sensors.

Operations

Flight geography

Flight geography describes the planned operational area, including ground risk buffers and contingency volumes around the flight path.

Licences

A1/A3 certificate

The A1/A3 certificate of competency covers subcategories A1 and A3 in the open category — the baseline remote pilot qualification for most consumer drones.

Licences

A2 certificate of competency

The A2 certificate allows closer operations to uninvolved persons with C2-class drones under defined conditions, including low-speed mode.

Licences

STS

Standard Scenario

An STS is a pre-defined specific-category operation published by EASA with standard mitigations, allowing a lighter authorisation path than a full operational authorisation.

Licences

Remote pilot certificate

The remote pilot certificate of competency proves you passed the relevant theoretical exam (A1/A3, A2, or STS) for a defined scope.

Licences

LUC

Light UAS Operator Certificate

A LUC lets an organisation self-authorise certain operations after demonstrating safety management capabilities to the NAA.

Regulatory

NAA

National Aviation Authority

Each EASA member state designates an NAA to implement drone rules nationally — exams, registrations, and zone publications.

Regulatory

EASA

European Union Aviation Safety Agency

EASA develops harmonised aviation rules for EU member states, including the drone regulatory framework in Regulations 2019/947 and 2019/945.

Licences

Open category

The open category covers low-risk drone operations without prior operational authorisation, split into subcategories A1, A2, and A3 by risk.

Licences

Specific category

The specific category covers higher-risk operations requiring an operational authorisation, a declaration, or compliance with a published STS.

Licences

Certified category

The certified category applies to the highest-risk UAS operations, aligned with manned aviation certification principles.

Drone Classes

C0 class

C0-class drones are very light open-category aircraft under 250g with defined safety requirements under EU 2019/945.

Drone Classes

C1 class

C1-class drones are open-category aircraft under 900g with technical mitigations such as noise and altitude limits.

Drone Classes

C2 class

C2-class drones weigh up to 4kg and are designed for A2 subcategory operations with low-speed mode and remote ID.

Drone Classes

C3 class

C3-class drones are larger open-category aircraft operated mainly under A3 rules, away from residential areas.

Drone Classes

C4 class

C4-class drones are legacy-format aircraft up to 25kg operated under A3 limitations in the open category.

Drone Classes

Legacy drone

Legacy drones are aircraft placed on the market before C-class rules without a class label, operated under transitional open-category limits.

Drone Classes

Private build UAS

A privately built UAS is assembled by an individual for personal use, with specific mass limits and operational restrictions.

Airspace

CTR

Control Zone

A CTR is controlled airspace established around an aerodrome where ATC provides separation services — drone operations are heavily restricted.

Airspace

ATZ

Aerodrome Traffic Zone

An ATZ is airspace around an aerodrome where traffic patterns form; drone flights typically need clearance or are prohibited.

Airspace

UAS geographical zone

UAS geographical zones are published areas where drone operations are restricted or require conditions, shown on national geo-awareness maps.

Airspace

No-fly zone

A no-fly zone prohibits or severely restricts drone flights, often around airports, critical infrastructure, or events.

Airspace

Restricted airspace

Restricted airspace limits entry to protect national security, public order, or sensitive activities; drone access usually needs permission.

Airspace

U-space

U-space is a set of services supporting safe, efficient drone access to airspace, including registration, geofencing, and traffic information.

Airspace

ATC

Air Traffic Control

ATC provides air traffic services in controlled airspace; coordination may be required for certain drone operations near aerodromes.

Airspace

NOTAM

Notice to Airmen

A NOTAM is a notice distributing time-sensitive information about hazards or restrictions, including temporary drone no-fly areas.

Airspace

AGL

Above Ground Level

AGL measures altitude relative to the surface directly below the aircraft; the standard open-category height limit is 120m AGL.

Operations

Remote ID

Remote ID broadcasts identification and position data so authorities and other airspace users can detect compliant drones.

Operations

Geofencing

Geofencing uses GPS or geo-awareness data to prevent drones entering restricted zones, often via manufacturer fly-safe databases.

Operations

Ground risk

Ground risk is the risk of a person on the ground being struck by the aircraft or its parts.

Operations

Air risk

Air risk is the risk of collision with other airspace users, including manned aircraft.

Regulatory

75% pass threshold

EASA theoretical exams require at least 75% correct answers — for the A2 exam that means 23 of 30 questions.

Operations

Uninvolved person

An uninvolved person is someone not participating in or aware of the drone operation; open-category distance rules protect them.

Operations

Populated area

A populated area has a concentration of people not directly involved in the flight; A3 operations must stay away from them.

Operations

Low-speed mode

Low-speed mode is a C2 drone function limiting speed so the remote pilot may reduce horizontal distance to uninvolved persons to 5m under A2.