These drones fall into the higher risk categories of drone operations called ‘Specific’ and ‘Certified’. As part of CAA approval, the airworthiness of the aircraft is established, as well as the nature of the operation and any hazards that could be encountered. This ensures that the risk of something going wrong on the drone is minimised and that detailed response plans are immediately available to mitigate the effects of any problems experienced. For drones in the ‘Specific’ category, the CAA considers each application by a drone operator on a case-specific basis, assessing an operator’s Operating Safety Case (OSC) and granting an Operational Approval (OA) when satisfied.
The ‘Certified’ category involves drones that are certified to the same rigorous standards as crewed aircraft (i.e., general certification of aircraft and operators, and the licensing of pilots), and therefore does not require assessments on a case-specific basis.
Drones in the ’Open’ category are lower risk, and are limited by a number of factors, all of which must be met: maximum weight less than 25 kg; flown within Visual Line Of Sight (VLOS) and below 400 ft (120 m); and not flown within 150 m of residential, commercial, industrial or recreational areas, or within 50 m of uninvolved persons.
There is a further sub-category of the ‘Open’ category that is even lower risk, involving drones that weigh less than 250 g, which can be flown in residential, commercial, industrial or recreational areas near uninvolved people because the damage they can inflict is very small owing to their small mass. Toy drones would fall into this sub-category.