Distinguishing a drone from a model aircraft
The Explanatory Note on UAS Prototype Commission Regulation on Unmanned Aircraft Operations express the difficulty of distinguishing "drones" from model aircraft, as both indeed are Unmanned Aircraft.
Have you considered defining "drones" based on their autonomous flight capabilities?
For example, an UA which can fly autonomously (i.e. without active control input from the remote pilot) is a drone. A civil UA without autonomous flight capabilities is a model aircraft.
Extending this example, logic says that the type of drone which is a potential danger to public airspace safety, is the drone which anyone can buy and fly.
Model aircraft such as airplanes, helicopters and even multirotors have been available for most people to buy for many years. Yet, without the right knowledge and skills it is not possible to keep a model aircraft airborne long enough to pose a threat to anyone. In the process of gaining the necessary knowledge and skills to fly, a person will inevitably also learn the rules and regulations associated with model flying. The model flying associations has done an invaluable job here.
There are two criteria which together identify the civil UA in need of new regulations:
- the UA can fly autonomously, i.e. without active control input
- the UA is available for consumers to buy in a ready-to-fly package (or requiring no advanced assembly)
If either of these criteria are not met, the UA does not have any higher risk of endangering public airspace than any of the model aircraft which have been available for the past 70 years.