If you manufacture a drone for the European market, the class mark is your product's passport: a label from C0 to C6 that tells operators which rules they may fly it under. For a hardware startup it's also a design constraint set worth reading before the CAD freeze, because several requirements are architecture, not paperwork.
Where class marks sit in the framework
Regulation 2019/947 governs operations; Regulation 2019/945 governs the product. The class mark is the bridge: operators read it to know what they're allowed to do. C0–C4 map to Open-category subcategories; C5 and C6 exist for the Specific category's Standard Scenarios. It rides alongside — not instead of — regular CE obligations (EMC, radio equipment directive for your radios, safety of the battery system).
The classes at a glance
| Class | Key limits | Signature requirements | Enables (Open cat.) |
|---|---|---|---|
| C0 | <250 g, ≤19 m/s | Basic safety, max height limit setting | A1 — over people incidentally |
| C1 | <900 g or <80 J impact | Remote ID, geo-awareness, lights, no sharp edges, standards compliance | A1 — near people |
| C2 | <4 kg | C1 set + low-speed mode (3 m/s), tether option, stronger structural reqs | A2 — close to people (30 m / 5 m low-speed) |
| C3 | <25 kg, <3 m dimension | Remote ID, geo-awareness, C2-style systems, data link loss behaviour | A3 — away from people |
| C4 | <25 kg, no automation | Essentially model aircraft carve-out | A3 |
| C5 | <25 kg (C3 derivative) | + low-speed mode, enhanced containment, kill/termination capability | STS-01 (VLOS urban, controlled area) |
| C6 | <25 kg | + programmable containment, flight termination, position accuracy reqs | STS-02 (BVLOS, sparse areas) |
The requirements that are secretly architecture
- Direct Remote ID — broadcast of operator registration, position, and take-off point. A module or integrated function, with antenna placement implications on carbon airframes.
- Geo-awareness — the aircraft must ingest airspace limitation data and warn the pilot: a software feature touching your GCS, your flight controller firmware and your update pipeline.
- Low-speed mode (C2/C5) — a selectable 3 m/s cap, implemented in the flight stack, verifiable in test.
- Containment and flight termination (C5/C6) — enhanced geofencing and an independent means to end the flight; on C6, accuracy requirements that pull your GNSS architecture into the compliance story.
- Sound power limits — measured, labelled, and mostly determined by propeller choices you make in month two.
The conformity process, without the mystery
- Map your product to a class — and to a target operation: it's common to design one airframe family targeting C2 and C5/C6 variants (much hardware shared, containment features added).
- Work against harmonised/consensus standards where published (EN 4709 family): following them grants presumption of conformity, and their test methods are effectively your verification plan.
- Engage a notified body early for classes that need one — capacity is finite and lead times are real. Bring a technical file skeleton to the first meeting, not a prototype and optimism.
- Build the technical file as you engineer: design data, risk analyses, test reports (your flight test evidence does double duty), manufacturing controls, user manual. The Declaration of Conformity at the end is one page standing on that pile.
- Plan for change management: firmware updates that touch marked functions (geo-awareness, low-speed mode, containment) re-open conformity questions — version discipline is a compliance function.
Class marking makes sense when you sell aircraft as products into Open/STS operations. If you operate your own aircraft under a SORA-based authorisation — the common startup pattern — you may not need a class mark at all initially; your evidence lives in the authorisation instead. Many teams defer marking until the product and market stabilise, then mark to unlock the broader customer base. Sequence deliberately; don't pay for both regimes before either earns revenue.
Frequently asked questions
What does a C1 or C2 class mark on a drone mean?
Class marks C0–C6 certify that a drone meets the product requirements of EU Regulation 2019/945 for that class — mass/energy limits, geo-awareness, remote ID, lights, and for C2 features like low-speed mode. The mark determines which Open-category subcategories (or Standard Scenarios, for C5/C6) the aircraft may be used in.
Does my drone product need a class mark to be sold in the EU?
To be operated in the Open category to its full potential, yes — unmarked drones are restricted to the most conservative rules. Aircraft flown under a Specific-category authorisation don't need a class mark (except when using Standard Scenarios, which require C5/C6).
Can a startup self-certify a drone class mark?
For C0 (and largely C4) the manufacturer can self-assess against the requirements. Higher classes involve harmonised standards and notified-body conformity assessment — third-party involvement, testing evidence and real lead time. Budget months, not weeks.
This is independent educational content — not legal, spectrum, conformity-assessment or flight-safety advice. Rules change and differ by country. Verify current requirements with EASA, your national aviation authority, your national spectrum regulator (in Belgium, BIPT) and qualified counsel before you operate or rely on any figure here.