Note: This post is written from a Hungarian perspective. References to registration platforms, authorities, and procedures reflect Hungarian practice. The EU open category rules themselves apply across all EU member states, but national implementations may vary - check your local aviation authority for country-specific details.

EU drone regulations are full of terms that aren’t explained anywhere obvious. This is a plain reference - what each term means, why it matters, and how it connects to what you can actually do.

Classes Link to heading

C0 Link to heading

Max. 250 g - the most permissive class

The lightest category. Low enough collision energy that it can fly over individual people (never over crowds). No Remote ID required. Camera drones still require operator registration. The A1/A3 online test is recommended but not mandatory.

C1 Link to heading

Max. 900 g - near people, with Remote ID

Can fly near people in A1 but should avoid flying directly over them. Remote ID and operator registration are always required, regardless of camera. A1/A3 online test required. FPV flight requires a visual observer.

C2 Link to heading

Max. 4 kg - the only class that enters A2

The only class permitted to fly close to people in the A2 zone. Requires A1/A3 test plus the paid A2 CoC exam. Must have a slow mode (max. 3 m/s). Remote ID and registration always required.

C3 Link to heading

Max. 25 kg - uninhabited areas only

Restricted to A3 operations. Must stay at least 150 m from any residential, commercial, industrial, or recreational area. Remote ID required. A1/A3 test required. Max. dimension 3 m in any direction.

C4 Link to heading

Max. 25 kg - traditional RC and FPV racing

Traditional radio-controlled model aircraft and GPS-free FPV racing drones. No Remote ID required. Automated flight modes (GPS hold, follow-me, waypoints) are prohibited - stabilisation only. A3 zone only.

Operational zones Link to heading

A1 Link to heading

Over or near people - small drones only

C0 can fly over individuals (not assembled crowds). C1 can fly near people but should avoid direct overflight. No fixed minimum distance, but intentional overflight of uninvolved people is not permitted for C1.

A2 Link to heading

Close to people - C2 drones only

Minimum 30 m horizontal separation from uninvolved people in normal mode. In slow mode (max. 3 m/s) this reduces to 5 m, but never less than the current flight altitude. A2 CoC required on top of A1/A3 test.

A3 Link to heading

Away from people - all open category drones

At least 150 m from any residential, commercial, industrial, or recreational area. All open category classes can operate here. Least restrictive in terms of proximity, but requires genuinely uninhabited surroundings.

Certification and registration Link to heading

A1/A3 online test Link to heading

Free, no exam centre, valid indefinitely

An open-book online test covering basic airspace rules, safety, and regulation. No time limit, no fee. Required for C1, C2, C3, C4. In Hungary available at mydronespace.hu.

A2 CoC (Certificate of Competency) Link to heading

Paid exam, required for A2 operations

A proctored exam at a certified test centre. Covers meteorology, drone performance, technical knowledge, and risk assessment. ~30 questions. Cost typically €50–150. Prerequisite: valid A1/A3 test. Required to fly C2 drones in the A2 zone. Valid indefinitely.

Operator registration Link to heading

Required for most drones

Registering yourself as the drone operator with the national aviation authority. Gives you an operator ID that must be marked on the drone and broadcast via Remote ID during flight. Required for all C1+ drones and for any C0 drone with a camera.

Technical terms Link to heading

MTOM (Maximum Take-Off Mass) Link to heading

Total weight at takeoff, everything included

Battery, camera, payload, accessories - all of it. This is the number that determines your drone’s class or legacy weight band. The spec sheet weight is usually without accessories. Weigh it as you actually fly it.

Remote ID Link to heading

In-flight identity broadcast

Transmits the drone’s position, altitude, and operator registration number via radio during flight. Conceptually similar to ADS-B on manned aircraft. Required on C1, C2, C3. Allows authorities to identify what’s flying and who operates it.

Geo-awareness Link to heading

Airspace restriction awareness built into the drone

The drone uses GPS to compare its position against a database of airspace restrictions - no-fly zones, altitude limits, CTR/ATZ boundaries. Required on C1, C2, C3. Does not automatically prevent flight but must alert the pilot and require deliberate override to enter restricted areas.

Slow mode Link to heading

Speed-limited mode on C2 drones

Caps horizontal speed at 3 m/s. When active, the minimum separation from people in A2 drops from 30 m to 5 m (never less than flight altitude). Must be a built-in hardware/software feature - manually flying slowly does not count.

Uninvolved person Link to heading

Anyone not part of the operation

Anyone who hasn’t consented to being overflown and isn’t participating in the drone activity. The key figure in determining which zone applies. Random pedestrians are uninvolved. People at your organised shoot who signed consent forms are involved.

Assembled crowd Link to heading

Prohibited overflight in every class and zone

A group where individuals cannot freely move away - concerts, festivals, demonstrations, stadium events. Flying over an assembled crowd is prohibited without exception across all open category classes and zones. Not a distance question, not a height question.

Visual observer Link to heading

Required for FPV flight

A person who maintains direct visual line of sight on the drone while the pilot flies FPV. Not a co-pilot - they don’t control anything. Their job is to watch the airspace and alert the pilot to hazards. Must be physically present and attentive. Required for FPV operations in C1 and above.

Flight rules Link to heading

VLOS (Visual Line of Sight) Link to heading

You must be able to see your drone with your own eyes

Direct, unaided visual contact with the drone at all times - enough to judge its orientation, altitude, and flight path. FPV goggles alone do not satisfy this requirement. A visual observer watching the drone while you fly FPV does satisfy it.

FPV (First Person View) Link to heading

Camera feed in goggles - legal but requires an observer

Flying with video goggles showing the drone’s camera feed. Legal under open category rules, but since you can’t see the drone while wearing goggles, a visual observer is required to maintain VLOS. The observer needs no licence but must be present and watching.

AGL (Above Ground Level) Link to heading

Altitude measured from the ground below, not sea level

The open category ceiling is 120 m AGL. This means from the surface directly below the drone, not from sea level. Flying over a building: your 120 m starts from the roof. Flying over a hill: from the hilltop. Check terrain before planning altitude.

Airspace Link to heading

ATZ (Aerodrome Traffic Zone) Link to heading

Controlled airspace around smaller aerodromes

Typically extends 2.5 NM from the aerodrome centre, up to a defined altitude. Drone flight inside ATZ requires prior coordination with the aerodrome. Boundaries visible in MyDroneSpace.

CTR (Control Zone) Link to heading

Controlled airspace around major airports

Extends further than ATZ, often reaching to ground level. Flying in CTR without authorisation is prohibited. Common around major cities with nearby airports.

P / R / D zones Link to heading

Zone Name Meaning
P Prohibited Flight completely forbidden at all times. Military areas, critical infrastructure.
R Restricted Flight restricted, may be permitted under specific conditions or time windows. Check MyDroneSpace.
D Dangerous Hazardous activities in the area (firing ranges, parachute zones). Not automatically prohibited but requires awareness.

NOTAM (Notice to Airmen) Link to heading

Temporary airspace change - check before every flight

Issued by aviation authorities to announce temporary restrictions: military exercises, events, construction near aerodromes. A normally clear area may be restricted on a specific day. Available through official authority portals and most airspace apps.