• In the absence of airworthiness certification, the oversight of persons not under the control of the pilot is restricted and described in the conditions of the Permission issued by the CAA.
For UA of 20 kg and below, ANO 2009 Articles 166 and 167 define the separation distances that must be applied. For UA operations over 20 kg, the overflight of persons may be allowed subject to the assessment of the UAS Operating Safety Case and /or airworthiness certification and appropriate operational procedures such as Ballistic Recovery Systems (BRS) (e.g. parachutes).
• The safety case for the overflight of people must include an assessment of the Kinetic Energy Limits and the method of flight termination (e.g. BRS). Two crash scenarios must be considered in determining the impact kinetic energy of the UA, as follows:
⁃ a free-fall from 400 ft for all UA;
⁃ additionally, for UA capable of high forward speed, a maximum impact speed (set as 1.4 x maximum achievable steady speed in level flight).
• Assuming negligible aerodynamic drag, an object dropped from 400 ft will hit the surface at 95 kt and the kinetic energy at impact will be 95 kJ if the mass of the object is 80 kg. If the object exhibits significant aerodynamic drag (without reliance upon any on-board parachute deployment system), the impact velocity will be less and a higher mass may be permissible without exceeding a calculated 95 kJ.
• In the second scenario and with a maximum speed of 70 kt, 95 kJ equates to a mass of 75 kg. The mass can be increased up to a maximum of 150 kg, provided the maximum achievable steady level flight speed is sufficiently low that the energy limit is not exceeded (e.g. at 150 kg a maximum speed of 49 kt is permitted).