Abstract
<div class="section abstract"><div class="htmlview paragraph">The flight area of drones and other unmanned aerial vehicles (UAVs) had been highly restricted but has been relaxing, including flights beyond the scope of sight. Deregulation without aircraft-reliability improvement increases the risk of accidents. However, demanding high reliability for all aircraft leads to an increase in the price of the aircraft. Therefore, if airspace restrictions are relaxed for more reliable aircraft, the cost of higher reliability and its benefits can be balanced. This will improve efficiency and optimize cost-effectiveness. The purpose of this proposal is to balance the cost of aircraft-reliability improvement (which allows flight to continue in the event of a failure) and its advantages. Specifically, the author proposes rules that apply more relaxed airspace restrictions to UAVs with higher FCLs (Flight Continuity Possibility Levels) and stricter airspace restrictions to those with lower FCLs. The FCL does not only refer to the distance or time that can be flown but also includes the ability to reduce the descent rate or lessen the impact on landing using the remaining flight resources at the time of failure. Technological development has also been underway to ensure that automobile powertrain systems and electric power-steering systems continue to operate in the event of failure, and by using these technologies, it is possible to increase the FCL at lower cost.</div></div>