The airspace in western Europe is one of the most complex airspaces globally. With the air space already operating near maximum capacity, innovations are needed to increase airspace efficiency. This research aims to design and test a debunching concept for inbound air traffic to increase the efficiency of the arrival traffic stream. A probabilistic debunching concept is created for the Initial Approach Fix using Probability Density Functions fitted on the errors in predicted arrival times provided by the EUROCONTROL Enhanced Tactical Flow Management System Flight Data messages (EFD). A bunching probability is detected when two or more aircraft have a probability of arriving at the Initial Approach fix simultaneously or within the required Wake Category Separation. A debuncher is created using a Constrained Genetic Algorithm that decreases the bunching probability by imposing en-route delay on arriving air traffic. The results show that the bunching probability increases with shorter prediction horizons as the uncertainty in the arrival estimates decreases. It is shown that with the probabilistic debunching method, it is possible to decrease the delay in the Arrival Manager by imposing delay en-route. However, at prediction ranges before 40 minutes before arrival at the IAF, the decrease in the AMAN delay is not consistent, indicating that the trajectory prediction uncertainty at this range is too high. Furthermore, the decrease in the AMAN delay is often lower than the imposed delay by the debuncher, showing that the decrease in AMAN delay comes at the cost of extra delay en-route. It is concluded that when the uncertainty in the trajectory predictions is decreased, the effectiveness of the debuncher increases and the effect on the Arrival Manager is improved, indicating improved arrival efficiency.

Major delivery companies such as DHL, UPS or Amazon have been developing small drones to deliver packages. This alternative to truck delivery is expected to start operating in the near future. The advantages of it are its speed, price, safety and sustainability: parcels would not be subjected to traffic and they would be delivered within an hour, it is 10% less expensive and it means a 73% reduction in CO2 emissions when compared to truck delivery, as well as a relieve in the road traffic network. The only drawback is that the noise produced by current drones is deemed by humans as more annoying than car noise due to its high frequency. The mission of the Silent Delivery Drone project is to provide a drone delivery system that is faster, less expensive and has lower emissions than truck delivery while complying with Dutch noise regulations. The presented innovative configuration is a combination of a quadcopter, suitable for Vertically Taking-Off and Landing (VTOL) in densely populated regions, and a flying wing, optimized for the cruise phase. It consists of a horizontal propeller used during cruise and four vertical propellers for VTOL. The drone can carry a payload of up to 2.5 kg, which corresponds to 89% of the packages delivered yearly worldwide. Four packages can be delivered while flying the maximum range of 30 km. Thanks to the low required revolutions per minute, the absolute maximum noise caused by the drone is 58 dBA at take-off from 7.5 m and 25 dBA during cruise from a distance of 120 m. This meets the Dutch night noise regulations which stablish a peak noise level of 65 dBA and average noise level of 40 dBA. We believe that a fleet of Silentium drones would revolutionize the way we perceive package delivery and it would mark the next step towards a greener, smarter and more connected future.