An unmanned combat aerial vehicle (UCAV),[https://technoview2016.wordpress.com/2016/01/22/drone-warfare/] also known as a combat drone or drone, is an unmanned aerial vehicle (UAV) that is usually armed (aircraft ordnance), such as with missiles. Aircraft of this type have no onboard human pilot. These drones are usually under real-time human control, with "the human's role in UCAV system [varying] according to levels of autonomy of UCAV and data communication requirement[s]".