| H1 | UAV infringes separation limits from another aircraft. |
| H2 | UAV exceeds the flight envelope, such as speed and roll angle. |
| H3 | UAV exceeds the operation envelope, such as vertical and horizontal limits. |
| H4 | UAV fly over populated or sensible areas, such as military, nuclear plant, forest with fire. |
| H5 | UAV is unable to continue flying due to internal health or weather. |