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C-DRONE GUIDE · 4 AUGUST 2026

Flying a drone above 120 m in France: the obstacle exemption, the CERFA 15478 file and SORA for professionals

A pilot inspecting a 60 m telecom pylon, a wind turbine with a 150 m blade tip height or a 200 m industrial chimney runs almost immediately into a limit most missions never think about: the 120 m above-ground ceiling that bounds open-category flight. That ceiling is not negotiable case by case, but nor is it absolute: the regulation carries a precise exemption for tall obstacles, and a procedure for going further when it falls short. Here is exactly what the text allows without a waiver, and the steps to take when a mission exceeds that frame.

Published on 4 August 2026, reviewed on 24 August 2026 — regulations in force as of August 2026.

The 120 m ceiling, and why it catches up with inspection missions fast

Regulation (EU) 2019/947 and its French transposition, the decree of 3 December 2020 on the use of airspace by unmanned aircraft, sets the maximum open-category flight height at 120 m above ground (AGL — measured from the point on the ground directly beneath the drone, not from the take-off point). Over a flat site, a roof or a farm plot, that limit leaves a comfortable margin: the vast majority of photogrammetry, orthophoto or construction-monitoring missions fly well below it and never come close.

It becomes the first constraint to check, though, as soon as a structure exceeds roughly a hundred metres: a telecom pylon — see our guide to telecom tower inspection by drone —, a wind turbine, covered in our guide to wind turbine blade inspection, a water tower, an industrial chimney or a drying tower. The pilot then needs to know exactly where free flight stops and the paperwork starts, before even proposing a date to the client.

The obstacle exemption: up to 15 m above a pylon or turbine, no waiver needed

Article 8 of the 3 December 2020 decree carries a tolerance built precisely for these situations: within a horizontal radius of 50 m around an artificial obstacle taller than 105 m — pylon, antenna, wind turbine, chimney —, the drone may fly up to 15 m above the top of that obstacle, even where this exceeds 120 m measured from the ground. On a wind turbine with a 150 m blade-tip height, that margin is usually enough to cover the whole structure without leaving the open category.

Two conditions bound this tolerance: it waives no other rule (airspace zone, distance to third parties, subcategory A2 or A3 depending on how close ground personnel are — see our guide to the open versus specific category), and it assumes the agreement of the obstacle's owner or manager: the pylon operator, the wind farm manager, the industrial firm that owns the chimney. That point is settled upstream, alongside site access: without that written agreement, flying beyond 120 m stays out of frame, whatever the obstacle's height. A 90 m pylon, below the 105 m threshold, does not benefit from this exemption either: the ordinary 120 m ceiling then applies, which usually leaves enough margin to inspect it in full anyway.

Beyond the exemption: the CERFA 15478 file and a SORA study

When a structure far exceeds the exemption — a 250 m chimney, a survey that must cover a larger volume of airspace than the 50 m radius alone —, or when a mission needs to exceed 120 m without an eligible obstacle to justify it, the operation must move into the specific category. The request is formalised with the CERFA 15478 form, filed with the regional civil aviation safety directorate (DSAC) responsible for the flight zone: it checks the flight's compatibility with airspace organisation, particularly near an aerodrome or a controlled zone. Processing takes weeks — generally three to six — which rules out any last-minute improvisation.

Depending on how complex the flight is, the file rests on a European standard scenario (STS) or on a full risk analysis under the SORA methodology (Specific Operations Risk Assessment), developed by JARUS and adopted across European authorities: it separately assesses ground risk and air risk to set the level of rigour required. A study by Jesús Capitán and coauthors, presented at ICUAS in 2019, concretely illustrates this approach applied to a professional image-capture use case (see the study on Google Scholar): it shows that most of the work goes into precisely characterising the airspace volume overflown and the third parties exposed, not the height itself. Our guide to BVLOS, STS and SORA details this procedure for beyond-visual-line-of-sight flights, which follows a very similar logic.

What this means for the client: lead times and price

For a project owner or an operator commissioning an inspection, three habits avoid bad surprises. First, ask for the structure's exact height before setting a date: under 105 m, or simply under 120 m, the mission stays within the standard frame and can be scheduled within days. Second, supply the written agreement of the obstacle's owner or manager promptly if the pilot requests it: it is often the only document holding up an otherwise ready flight. Third, build in the processing time as soon as a CERFA 15478 file or a SORA study is needed: better to start it at quotation stage than at project handover.

On price, the gap stays modest as long as the obstacle exemption is enough — the mission is then billed like any tall-structure inspection, along the lines of our guide to telecom tower inspection by drone. It widens noticeably once a specific-category file becomes necessary: putting the file together, the wait for approval and, often, a more qualified pilot commonly add several hundred to a few thousand euros excl. VAT depending on complexity, on top of the flight itself. The contractor should be able to justify this framework point by point — it is also a good indicator of how serious they are, as our guide to professional drone liability insurance notes for the other documents worth requesting before a flight. For the general price structure, see our guide to how much a drone service costs. Request a quote, stating the height of the structure to inspect.

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