Under 250 grams
A drone under 250 grams is the lightest class the United Kingdom requirements recognise, and it is exempt from some of what heavier machines carry rather than from the rules as a whole. The 250 gram boundary is a published threshold in the Civil Aviation Authority scheme, and it is measured on the aircraft as it flies, with the battery, the propellers and anything else fitted. Below the line, the identifier that attaches to the person flying is not triggered by weight, and the separation distances are at their most permissive. Above the line, both identifiers and the fuller set of distances come into play. Almost everything else, including the height ceiling, is unchanged by weight.
What the 250 gram class actually is
The class is a mass band, not a category of machine, and it exists because kinetic energy scales with mass. An airframe of 249 grams falling from height carries a fraction of the energy of a two kilogram camera aircraft, and the requirements are graded accordingly. That is the whole logic of the boundary and it explains why manufacturers design so precisely against it: a great many popular machines are specified at just under the figure with their standard battery fitted, which is also why fitting a larger pack, propeller guards or a payload can take an aircraft over the line without the owner noticing.
Who the lightest class falls on
The lightest class falls on the aircraft, not on the person, and that is what makes it different from the identifiers around it. Weight is an attribute of the machine and it is fixed on the day: a person does not qualify for the light class, an airframe does. Two people flying the same 200 gram machine are in the same position on weight, whatever their experience.
The consequences, though, land on two different people. The flyer identifier is a question about whoever is at the controls, and weight below the boundary is what keeps it from being triggered. The operator identifier is a question about whoever is answerable for the machine, and there weight is not the only test, because a camera on board bears on it as well. So a household with one light camera drone can find that the flyer side is quiet and the operator side is not. The drone licence question sets out the two identifiers in full.
What flying in this class asks of you, in order
- Weigh the aircraft on a kitchen scale exactly as it flies, rather than trusting the figure on the box.
- Re-weigh it whenever anything changes: a larger battery, propeller guards, a lens filter or a strut.
- Check whether it carries a camera or another sensor capable of recording a person, since that is the attribute the operator side turns on.
- Register as the operator if the camera or the weight calls for it, and mark the identifier on the airframe.
- Fly to the same 400 foot ceiling and the same requirement to keep the aircraft in unaided sight that every other class works to.
- Check the airspace above the take-off point before every flight, because the light class buys no relief there.
Caution
A machine specified at just under the boundary has almost no margin. Fitting a heavier aftermarket battery to gain flight time is the commonest way of crossing the line without knowing, and it also strains a power system designed around the original pack. Weigh the aircraft after any change, and never modify a battery or its housing to make it fit.
Where the exemption does not apply, and what it never covered
The exemption does not apply beyond the identifiers and the separation distances, and a column for each side of the boundary is the clearest way to see how narrow that is.
| Attribute | Under 250 g | At or above 250 g |
|---|---|---|
| Height ceiling | 400 ft, 120 m | 400 ft, 120 m |
| Kept in unaided sight | Required | Required |
| Flight restriction zones | Apply in full | Apply in full |
| Flyer identifier | Not triggered by weight | Triggered |
| Operator identifier | Turns on whether a camera is fitted | Triggered |
| Separation from uninvolved people | Most permissive band | Larger distances, by class marking |
| Data protection for footage | Applies if a camera is fitted | Applies if a camera is fitted |
Read down the right-hand column and the pattern is plain. Weight buys relief on the identifiers and on the distances. It buys nothing at all on the ceiling, on the requirement to keep the aircraft in sight, on restricted airspace, or on what a camera records. A light machine flown into a flight restriction zone around an aerodrome is in exactly the position a heavy one would be.
The exemption stops at the airframe as well. It does not travel with the pilot, so a person who flies a light machine and then borrows a heavier one is in the heavier machine's position from the moment they take the controls. It does not survive a modification, since 249 grams plus a set of guards is not 249 grams. And it does not reach outside the United Kingdom: Canada, Australia and the European states each run their own weight boundaries and their own registration schemes, and the fact that several of them also use a 250 gram figure does not mean the consequences attached to it are the same.
It also stops at the camera. That is the single most important edge on this page. A camera on board changes the picture on the operator side even for the very lightest machines, and it brings the Information Commissioner's Office into the frame as the body that publishes guidance on recording identifiable people. A 190 gram machine with a lens is not in the same position as a 190 gram machine without one. The UK rules, in order shows how weight and camera sit alongside the other questions, and Insurance covers liability, which weight does not touch either.
The three things people get wrong about the boundary
The first thing people get wrong is that under 250 grams means outside the rules. It does not: it means outside two of them. Height, sight, airspace and data are all untouched by weight, and those four are what most enforcement is actually about. The second is that the figure on the box is the figure that counts. It is the manufacturer's specification for a standard configuration, and the aircraft in your hand may not be in that configuration. A scale settles it in ten seconds.
The third is that new rules regularly abolish or move the boundary. The class markings that came in with the current framework have changed what sits either side of the line and how the camera test is expressed, and further revision is expected as the scheme matures, but the 250 gram figure itself has been the durable part. What changes around it is the detail, which is why a page like this describes the shape of the requirement and points at the published source for the wording.
Is your own drone in the light class?
To establish whether an aircraft is in the light class, put it on a scale in flight-ready condition, with the battery in, the propellers on and anything else you fly with fitted, and read the number against 250 grams. Then look for a camera or any other sensor that can record a person. Those two facts are what the requirements are asking about, and together they decide which identifiers are in play and which band of separation distances applies.
They do not settle a particular case, and this page describes what the light class is exempt from rather than interpreting the requirements for any one aircraft or offering legal advice. The Civil Aviation Authority publishes the weight boundary, the class markings, the separation distances and the camera test, and the CAA revises them, so the version on the CAA's own pages is the one that describes the position for a flight made today.