C-DRONE GUIDE · 4 SEPTEMBER 2026
Airspace classes A to G, CTR, TMA, LTA: reading an aeronautical chart before a drone mission
Any professional remote pilot preparing a mission eventually runs into the vocabulary of manned aviation: they are told the site is "inside the CTR", that there is "a class D TMA overhead", or a client worries about a class C airspace spotted on a chart. These acronyms are not decorative, but they do not translate mechanically into a rule applicable to a drone: the ICAO classification describes the services air traffic control provides to aircraft — who must request a clearance, who must be on the radio, who is separated from whom. An open-category drone flying below 120 metres above ground, in contact with nobody, falls under none of those procedures. Its real constraint comes from elsewhere: the UAS geographical zones defined by France under EU regulation and shown as capped heights on the official restriction map. Understanding both systems, and knowing which one applies, avoids two symmetrical mistakes: giving up on a perfectly legal mission, or taking off inside a volume where you have no business being. Here is the vocabulary and the method.
Published on 4 September 2026, reviewed on 4 September 2026 — regulations in force as of September 2026.
What an airspace class describes — and what it does not
The classification comes from Annex 11 to the Chicago Convention, published by the International Civil Aviation Organization. It defines seven classes, A to G. Classes A to E are controlled airspace: an air traffic control service is provided there. Classes F and G are uncontrolled: only flight information and alerting services are available.
What each letter sets is a set of answers to four questions: which flights are admitted (instrument, visual, or both)? who is separated from whom by ATC? is a clearance — an explicit authorisation from control — required to enter the volume? is radio contact mandatory? In class A, visual flight is prohibited unless the authority grants an express waiver, clearance and radio are mandatory, and all flights are separated from each other. At the other end, in class E, a visual flight enters freely as long as visual meteorological conditions are met, with no clearance and no mandatory radio contact. Class G, finally, is the residual class: everything that has not been carved out as controlled airspace.
The key point for a drone operator: an airspace class is not a ban. It describes the level of service and the communication obligations imposed on aircraft circulating there. None of those obligations — clearance, radio, flight plan — makes sense for a 2 kg multirotor flying 60 metres above an industrial building. That is exactly why drone regulation built a parallel system, described below.
CTR, TMA, LTA, UTA, FIR: the vocabulary of volumes, and where they start
Classes qualify volumes, each carrying its own acronym. Telling them apart resolves most mission-planning worries on its own, because their floor differs radically.
- FIR (flight information region): the broadest division. Mainland France has five — Paris, Brest, Bordeaux, Marseille and Reims. It is a framework for providing information and alerting services, not a flight constraint.
- CTR (control zone): the volume protecting arrivals and departures at a controlled aerodrome. It is the only controlled airspace that starts at the surface and rises to a published level. In France a CTR is generally class D — but class A in the Paris region, where visual flight is prohibited except by waiver. This is the volume that genuinely concerns a drone, because it is the only one that touches the ground.
- TMA (terminal control area): covers one or several aerodromes, often stepped above and around the CTR. Its floor is never at ground level — around 700 ft at the lowest. Mostly class D in France, with class A, C or E TMAs depending on instrument traffic density.
- LTA (Lower Traffic Area): the lower airspace, from the higher of FL115 or 3,000 ft above the surface up to FL195. Class D, except above the Alps, the Pyrenees and the Verdon, and beyond 12 NM from the coast, where it is class E.
- UTA (Upper Traffic Area): the upper airspace, FL195 to FL660, class C, reserved for instrument flight.
Comparing the orders of magnitude settles the matter: an open-category drone is capped at 120 metres above ground, roughly 400 ft. FL115 is close to 3,500 metres, FL195 close to 6,000 metres. In other words, the LTA, the UTA and almost every TMA are out of a drone's reach: reading "class D TMA" on a chart says strictly nothing about a flight planned 60 metres above a roof. The only volume to worry about is the one reaching the ground: the CTR, whose practical handling — control unit agreement, protocol, lead times — is covered in our guide to drone missions inside an aerodrome CTR.
P, R and D zones and the very-low-altitude network: what is not an airspace class
A frequent mission-planning mistake: confusing classes with special-status zones. P (prohibited), R (restricted) and D (danger) zones are not airspace classes; they are volumes superimposed on the classification, with their own logic. The French order of 3 December 2020 on the use of airspace by unmanned aircraft deals with them explicitly in Article 4: overflight is prohibited in prohibited zones unless authorised, and in restricted or danger zones without the zone manager's agreement. The same article requires staying clear of the landing and take-off infrastructure listed in its Annex I, unless the air traffic control unit agrees.
A P zone can sit in class G — uncontrolled airspace, therefore "free" for manned aviation — and still be entirely closed to overflight. Conversely, a site in class D on the edge of a CTR can be perfectly flyable if a capped height is respected. Class and zone status are read independently.
A French specificity: the defence forces' very-low-altitude network, published as R zones and crossing the southern Alps, the Pyrenees, the Massif Central and the Vosges. Its geography appears on the map, but its activation changes daily and must be checked on the aeronautical information service's AZBA charts; our guide to flying over military zones covers this. Annex II of the same order adds a specific requirement: for certain airspace portions published in the French AIP (ENR 5.3.1.3) and for a list of eighteen military CTRs — Avord, Bricy, Hyères among others — an aircraft over 900 g flying within visual line of sight while the portion is active is subject to prior notification. Those portions are active Monday to Friday excluding public holidays, which is why a flight that is impossible on a Tuesday becomes possible on a Saturday.
These zones serve a concrete safety purpose: they keep drones away from flight paths where a pilot cannot rely on their eyes. A study published in 2019 in the International Journal of Aviation, Aeronautics, and Aerospace by Ryan J. Wallace, Jon M. Loffi and co-authors measured how well aeroplane pilots visually acquire a small drone on final approach: detection occurred in only 30 % of approaches — just 13.6 % when the drone was stationary — and successful detections clustered within 5° laterally and 10° vertically of the line of sight (see the study on Google Scholar). In other words: on approach, "see and avoid" does not protect a drone. The capped height published on the map does.
Why the rule that applies to your drone is not the airspace class
Implementing Regulation (EU) 2019/947 created, in its Article 15, a legal object distinct from the ICAO classification: UAS geographical zones. Each Member State defines them for safety, security, privacy or environmental reasons, may prohibit, restrict or condition flights there, and must make that information — including its period of validity — publicly available in a common, unique digital format. This mechanism, and this one alone, produces the restrictions enforceable against a drone.
In France, those zones take the form of the "Restrictions UAS catégorie Ouverte et Aéromodélisme" layer produced by the DGAC, available on the IGN's Géoportail and on cartes.gouv.fr. It shows, in simplified form and across mainland France, zones between 0 and 120 metres: the value read on the map — 0, 30, 50, 60, 100 or 120 m — is a height above ground level at the drone's position. It already incorporates, as concentric rings, the effect of CTRs, of P, R and D zones and of non-aeronautical restrictions. In other words: the translation work between the world of classes and the world of drones has already been done by the administration, and the output is a height in metres. Our guide to reading the Géoportail drone zone map covers its colour code and its limits, and our guide to the 120-metre maximum height deals with exemptions, notably obstacle following.
Two important caveats. First, this map only covers the open category and model aircraft: an operation in the specific category, under a standard scenario and with a protocol, obeys different conditions — sometimes more permissive, sometimes stricter. Second, it is static: the day's temporary restrictions must be read in the aeronautical information service's publications, as explained in our guide to NOTAMs and temporary restricted zones.
This decoupling between the classic classification and drone-dedicated volumes is not a transitional patch: it is the direction Europe has taken. The reference article on the U-space concept of operations, published in 2020 in the journal Aerospace by Cristina Barrado, Enric Pastor and co-authors from the European CORUS project, describes an architecture of very-low-altitude volumes with graduated services, designed to open airspace to emerging operations without forcing classic air traffic control categories onto them (see the study on Google Scholar). We set out the practical consequences for operators in our guide to U-space and digital airspace.
Summary table and preparation method
The table below summarises what each class implies for manned aviation, and its actual bearing on an open-category drone flight below 120 metres.
| Class | Flights admitted and obligations (manned aviation) | Use in France | Bearing on an open-category drone |
| A | Instrument only; visual flight prohibited except by waiver. Clearance and radio mandatory, all flights separated. | Paris region (airspace associated with Roissy, Orly, Villacoublay) | No direct obligation: the map's capped height applies — often 0 m in these areas |
| B | Instrument and visual; all flights separated from each other. Clearance and radio mandatory. | Not used | Not applicable |
| C | Instrument and visual; visual flight is controlled, clearance and radio mandatory. | UTA (FL195 to FL660) and the core of some major airports | None: volumes out of reach, except the controlled lower part of a major aerodrome |
| D | Instrument and visual; clearance and radio mandatory, traffic information between flights. | Most CTRs and TMAs, LTA | Only the CTR matters: it starts at the surface and imposes reduced heights in rings |
| E | Instrument and visual; visual flight enters without clearance or mandatory radio, in VMC. | LTA above the Alps, the Pyrenees and beyond 12 NM from the coast; some TMAs | None: floor far above 120 m |
| F | Instrument and visual; advisory service, no clearance. | Not used | Not applicable |
| G | Uncontrolled: flight information and alerting only, no clearance. | Residual class — the most extensive | No aeronautical obligation, but P, R and D zones and local restrictions may be superimposed |
The method that follows from this table comes down to four steps, in order. One: open the UAS restriction map and note the capped height at the exact mission point, keeping a dated screenshot. Two: identify the zone status (CTR, P, R, D) shown on click, and where relevant trigger the agreement request or prior notification — the military CTRs in Annex II of the order require that notification from 900 g upwards. Three: the day before the flight, check the day's publications — temporary restrictions and, in rural areas crossed by the very-low-altitude network, AZBA charts. Four: check ground-level law, which appears on no aeronautical chart: property, privacy, municipal orders, site rules.
Ranges observed in France in 2026 for the preparation work, excluding VAT and excluding the cost of the flight itself:
| Preparation service | Range (excl. VAT, 2026) |
| Aeronautical feasibility study for a site (map, publications, written note) | €150 to €400 |
| Preparing and following up an agreement request or aerodrome protocol | €300 to €800 |
| Specific-category operations file (standard scenario, declaration) | €800 to €2,000 |
| Multi-site study for an inspection campaign (per batch of sites) | on quotation, depending on geographic spread |
The regulatory information on this page reflects the rules in force in September 2026; classes, volumes and zones change with the aeronautical publication cycle and should be re-checked at the time of the mission. For a company, a local authority or an engineering firm unsure whether a flight over a specific site is feasible, request a quote stating the exact address, the intended flight height and the desired date: chart reading is part of the preliminary study.
Frequently asked questions
Can an open-category drone fly in class D airspace?
Yes, in the vast majority of cases — class D in itself prohibits nothing for a drone. The ICAO classification sets obligations (clearance, radio contact, separation) aimed at aircraft handled by air traffic control, not at a drone flying below 120 metres. What matters is the capped height shown at the flight point on the Géoportail "Restrictions UAS catégorie Ouverte et Aéromodélisme" layer. If that point falls inside a class D CTR, the map typically shows a reduced height there, or even 0 m in the immediate vicinity of the runways: that value is what counts, not the letter.
What is the difference between a CTR and a TMA when planning a drone flight?
The floor. A CTR is a control zone starting at the surface and rising to a published level: it is the only controlled airspace a drone can genuinely enter, and it is what generates the reduced-height rings around an aerodrome. A TMA is a terminal control area whose floor is never at ground level — around 700 ft at the lowest, often much higher. A flight at 60 metres beneath a TMA does not enter the TMA. In practice: if the map shows no restriction at ground level, the presence of a TMA overhead changes nothing in your planning.
Does flying in class G mean no formalities are required?
No. Class G is uncontrolled airspace for manned aviation, but it can be overlaid with special-status zones that do bind a drone: prohibited P zones, restricted R zones — including the defence forces' very-low-altitude corridors, activated on certain days and checkable on the AZBA charts —, danger D zones, environmental restrictions around nature reserves, and hospital helipads. Added to these are the military CTRs listed in Annex II of the order of 3 December 2020, which require prior notification for any aircraft over 900 g while active, plus all ground-level law (property, privacy, local by-laws) that appears on no aeronautical chart.