MTOM: the mass that decides everything, including the 250 g line
What MTOM covers, why it is not the bare weight of the drone, and the thresholds it triggers.
MTOM — Maximum Take-Off Mass — is the highest mass at which the aircraft can be operated, as declared by the manufacturer.
Manned aviation often says MTOW, Maximum Take-Off Weight. The two mean the same thing; European drone regulation uses MTOM.
It is not the weight of the drone on the scales
This is the mistake that costs most, because it is discovered during a check.
MTOM includes everything that leaves the ground:
- the aircraft itself;
- the battery fitted;
- the payload — camera, gimbal, sensor, release mechanism;
- any accessory attached: propeller guards, floats, lighting.
An aircraft advertised at 249 g without propeller guards can cross 250 g with them. The threshold does not negotiate.
The thresholds it triggers
In Europe, mass drives most of the applicable framework:
| threshold | what changes |
|---|---|
| 250 g | above it, the operator must register; a remote pilot attestation becomes required |
| 900 g | upper limit of subcategory A1, which allows incidental overflight of people |
| 4 kg | limit of subcategory A2, flight close to people |
| 25 kg | upper limit of the Open category |
⚠️ These thresholds are European. The UK, outside the Union's framework, applies its own — registration starts at 250 g there, but from 100 g if the aircraft carries a camera.
The special case of 250 g
It is the best-known threshold and the least well understood. In Europe a camera is enough to trigger the registration duty whatever the mass, as soon as it can collect personal data — except for aircraft falling under the toy directive.
In other words: going under 250 g lightens the obligations, it does not remove them.
Going further
- Drone regulations in France — the thresholds in their national context.
- Flying a drone in the United Kingdom — different thresholds, and the country's number-one trap.