Category A3 is one of the subcategories of the so-called "Open" category of drone operations, which includes flights with a low level of risk to the surroundings. The main rule for operating in this category is to fly far from people and maintain a minimum horizontal distance of 150 meters from residential, commercial, industrial, or recreational areas. Category A3 includes drones with a C3, C4 class identification label, privately built unmanned systems weighing up to 25 kilograms, or older drones without a label with a maximum take-off mass of 2 to 25 kilograms. The pilot must have passed the online examination for subcategories A1/A3 and be registered as an operator. As in other subcategories of the Open category, the pilot must maintain the drone within direct visual line of sight and must not exceed a flight height of 120 meters above the ground.