To overcome the disadvantages of radar vectors and to improve efficiency and safety of terminal airspace operations, EUROCONTROL has proposed the so-called Point Merge System (PMS) technique for merging inbound traffic flows. As the PMS provides better predictability, it can potentially offer significant fuel and environmental benefits as well as a considerable reduction of inbound delays.
The main goal of this project is to explore the potential benefits/drawbacks (environmental impact, capacity, delay, fuel efficiency and safety) of implementing PMS-based arrival management at Amsterdam Airport Schiphol (AAS).
In this research, a PMS route network is designed for two runway configurations at AAS. Using Mixed Integer Linear Programming (MILP) , an optimal PMS scheduling model has been designed. A case study is performed using current flight data to demonstrate the performance of the scheduling model and to find the potential advantages of implementing PMS-based arrival management at AAS. ... Read more

Multiple concepts for hybrid vehicles capable of both road and flight transport are becoming a reality. However, through incorporation of both flight and road hardware into one vehicle these designs become inefficient. The aim of this project is to design an alternative strategy for realising optimised hybrid vehicles. The objective of this project is to "Develop a personal transport vehicle suitable for commuter use on which flight hardware can be attached within 5 minutes, by 10 students within 10 weeks". This was derived from the mission statement which was to "Develop a faster and cheaper personal transport vehicle for the European market with detachable flight/road hardware that combines the advantages of road transport with flight capability". From this objective, the three most key requirements are that the vehicle shall have a road and flight configuration, that the flight hardware shall be separable from the road hardware and that the flight hardware shall be attached/detached from the road hardware within 5 minutes. When analysing the performance of the vehicle, typical flight stages and stalling configurations were investigated in terms of speed and power setting. At cruise speed, the 12 DEP (Distributed Electric Propulsion) propellers in the midsection of the wing are turned off and folded . However, for take-off and landing configuration, all the propellers are switched on. For fuel use two options are present. E10 gasoline for maximum range, or E85 for decent range, but a 70% lower eco-impact. 122 kW of power is supplied to the 6 outboard motors during cruise. The take-off distance is 450 m and the landing distance is 462 m. Two different propellers were designed and optimized for DEP and cruise conditions. To verify the noise requirements, a propeller noise analysis of the vehicle was carried out, since that is the largest contributer to overall vehicle noise. From that analysis it was concluded that the propeller noise level of the vehicle is 52.3 dBA at 1000 ft, which is low compared to other general aviation aircraft. The airfoil of the wing was selected using the design lift coefficient of 0.56. The airfoils chosen for the wing and tail are, respectively, theNACA4418 andNACA0012. Thewingwas designed to have an aspect ratio of 17, a surface area of 8.414 m2 and a span of 11.96 m. Using these values, the induced drag and pitching moment coefficients were determined. To investigate the overall efficiency of the aerodynamics of the wing, the lift over drag ratio (L/D) was calculated for each configuration. For cruise, landing and take-off, the L/D is 12.93, 7.74 and 9.48, respectively. The packaging of the vehicle resulted in the centre of gravity of the operative empty weight of the full configuration to act at 37.4% of the fuselage length at an empty mass of 1174.7 kg. The longitudinal and lateral stability and control of the vehicle were assessed. Due to the large downwash caused by the DEP propellers of the wing, a T-tail configuration was designed to move the tail away from the downwash and make it more effective. A fully-movable horizontal tail was necessary to counter the large lift coefficient and, consequently, the moment created by distributed electrical propulsion. The horizontal and vertical stabiliser were designed with a surface area of 2.42m2 and 1.1m2 respectively. After analysing the strengths and manufacturing methods of several materials it was found that the wingbox would be made using aluminium (AL7075-T6) with taper in the sheet thickness. Due to the slender wing, the weight of the wing became relatively high at 200 kg. For the skin, the most suitable material was polyester with glass fibres for its specific strength, price and compatibility with a foam or balsa core. For the linkage system, the location where the linkage is established needed to be considered. After investigating this, it was determined that the best place for the linkage would be the rear of the road hardware and the front of the flight hardware. For the linkage the Scharfenberg train coupling was used together with safety pins. The Scharfenberg connection was scaled down to suit the vehicle as it was originally designed for trains. After the final design is concluded, it is necessary to plan for future research in order to make this concept a reality. There are still uncertainties in how DEP affects the performance and aerodynamics of the concept. Therefore, it is recommended to conduct more lowspeed tests to properly establish those effects. Computational FluidDynamics (CFD) and wing tunnel testing is also recommended to visualise and analyse the fluid flow of the wing. A structural analysis using the finite elementmethod and full scale tests of themajor components are also recommended. As the coupling mechanism has never been used in aerospace application, further research into the adaptability and the integration of this mechanism should be performed. As a single-engine Private Pilot License is preferred, recommendations were also made on tests that need to be performed in order to make a case for the airworthiness authorities. ... Read more

In the year 2050, global anthropogenic radiative forcing from aircraft emissions are projected to increase significantly. Recent studies have considered climate optimized flight trajectories to be a promising measure to mitigate non-CO2 emissions’ environmental impact, which is highly sensitive to locus and time of emissions. Estimating the maximum mitigation potential from these trajectories requires accounting of air traffic regulations. As designing regulated climate optimal trajectories necessitates solving a hybrid optimal control system with unknown mode sequence and associated switching times, there is a need to build an efficient and systematic control technique. In this thesis, a bi-level optimal control algorithm is proposed for designing climate optimal cruise trajectories, the lower level calculates the optimal switching times and control
inputs of a fixed mode sequence and, the upper level updates the mode sequence with mode insertion which lower the cost locally. The problem for trajectory optimization is formulated here as a hybrid optimal control problem with a switched system and with a variable mode sequence, where step-climb and descent modes are included in the mode sequence. Optimal Control problems for minimizing operating cost and climate cost with fictitious climate cost functions (CCF), varying with altitude, are solved to study the performance of the algorithm. The algorithm is implemented within the Trajectory Optimization Module (TOM) by building a bi-level framework. The framework was validated by solving the operating cost optimal control problem. The maximum error between the cost reduction estimated by the algorithm and the actual cost reduction was found to be less than 15%. With high probability it can be stated that the bi-level framework is able to calculate an optimal mode sequence as the framework allow for zero entry modes in the mode sequence i.e. modes of zero duration. Although, careful consideration is required while selecting a mode for insertion as the framework is highly dependent on the sequence of the set of modes.

Despite a satisfactory performance of the bi-level optimal control technique there are few challenges which limits the scope of this technique. The maximum error was found to increase for optimal control problems with AirClim CCFs. The dependence of the AirClim CCFs on position of the aircraft influences the locus of the trajectory at each flight level. Because of this the the trajectories calculated in each iteration of the framework are found to be inconsistent. A flight trajectory guided by waypoints is proposed as a solution for future studies to handle the inconsistency between trajectories. As future studies are expected to focus on finding optimal mode definitions for designing climate optimal trajectories, the bi-level optimal control algorithm can act as an intermediary tool with which the researchers can systematically investigate cost benefits along the trajectories. ... Read more

Preface In the wake of the economical crisis of 2008, the shipping industry changed from a very profitable industry to a struggling one, aiming to optimize vessel operations in order to survive. Theories regarding route optimization based on weather and oceanic currents exist, but only few reliable industrial applications can be found. This, together with nowadays global environmental concerns, is where the roots of this project, aiming at developing a route optimization tool for seagoing vessels, based on real-life vessel data, short-term weather forecasts and oceanic currents and monthly averaged sailing conditions can be found. Due to the huge amount of fuel burned by seagoing vessels, achieving just a fraction of fuel savings already results in a significant reduction of global greenhouse gas production. The concept of weather routing is not new, but the results that can be achieved by using it are not widely documented. In order to quantify this, a weather route optimization tool has been developed. The availability of detailed hindcast datasets made it possible to incorporate monthly averaged sailing conditions in the optimization process, influencing the decision on which route to take when weather forecasts are not available anymore. Analysis of different ratios between forecasts, monthly averaged conditions and taking the shortest path to describe the sailing environment, led to the conclusion that forecasts are more reliable than sailing according to the monthly averages or taking the shortest path, as long as these forecasts are available. When no forecasts are available, using monthly averages as reference environment is favored over taking the shortest path. While evaluating randomly selected routes, it became clear that the usage of these monthly averaged sailing conditions can reduce the fuel consumption by 0.59 %, where the total effect of applying weather route optimization is found to be approximately 3.18 %. Due to the limited number of simulations performed and the unstructured nature of the data distribution, the 95 % confidence interval of the expected fuel savings ranges from 2.54 % to 4.02 %. When assuming the achieved savings are approximating reality, application of weather route optimization on the entire CMB fleet, containing close to 100 vessels, leads to a CO2 emission reduction almost 80 thousand metric tonnes per year. This is the result of a fuel consumption reduction of 23.5 thousand tons, which would roughly saves 9.35 million US Dollar in bunker costs. ... Read more

Condensation trails, or contrails in short, are the white lines that can often be seen trailing high-altitude jet aircraft. Due to their interference with the local energy balance of the atmosphere they contribute to anthropogenic climate change. Research has shown strategies with great contrail mitigation potential at relatively small fuel and/or time cost in free flight. This thesis attempts to quantify contrail mitigation potential in practical and realistic scenario by introducing flight planning as tool for mitigation. A tool was developed that plans and simulates flights from the Netherlands to several destinations in North America. From the results it is clear that at least 50% of contrails can be mitigated at less than 2% additional fuel through flight planning. The results have confirmed the hypothesis that large shares of contrails can be mitigates against a few percent additional fuel consumption and flight time. ... Read more

The popularity of Remotely Piloted Aircraft Systems (RPAS) is growing at an increasing rate as an alternative to manned aviation for different purposes and applications. So far, most of their operations have been of military character, but the demand for civil and commercial applications is growing exponentially. RPAS have been allowed to operate in segregated airspace by restricting other users from entering the volume associated to the operation of the RPAS. This temporary solution based on accommodating their operations on a case-by-case basis is not feasible on the long-term. Moreover, the latest forecast carried out by SESAR Joint Undertaking (SJU) reveals that by 2050 RPAS will represent 20% of the fleet. The available airspace is a scarce resource and is already saturated, which means that additional unmanned operations would not be possible
simultaneously. Integration in non-segregated airspace is the only manner in which the full benefits and capabilities of RPAS will be achieved, while maintaining the same levels of safety and efficiency as manned aviation.

In order to achieve a safe, efficient and transparent integration, a common regulatory framework and new technologies are currently under investigation. However, neither operational nor performance standards of RPAS integration have been addressed properly. For that reason, this project is focused on the development of a methodology to determine minimum operational and performance requirements by assessing the impact of RPAS operations on the Air Traffic Management (ATM) Network. The scope is limited to the en-route phase as a starting point since none of the flight phases have been analysed yet. This project is carried out in collaboration with EUROCONTROL.

RPAS are well known for presenting a wide range of performance characteristics, especially in terms of cruise speed and rate of climb. Thus, two different unmanned performance models have been chosen from the available performance models in the EUROCONTROL database: RP01 (MQ-9), which presents a similar performance to commercial aviation aircraft, and RP02 (RQ4A), which is considered a low-performance
RPAS in terms of cruise speed and rate of climb. Building on a base scenario in the Paris Control Terminal Area (CTA),Monte Carlo simulations of the air traffic have been performed in order to randomly vary the main input variable: the set of en-route flights that is substituted by unmanned aircraft. Two different scenarios have been analysed separately in order to establish the requirements: one for same-performance RPAS, and the
other for low-performance RPAS. In order to assess the impact, three different Key Performance Areas (KPAs) have been selected: capacity, efficiency and safety. These KPAs are in turn characterized by their corresponding Key Performance Indicators (KPIs), namely sector capacity, sector overload, flight time efficiency, flight path efficiency and number of potential conflicts.

Based on an analysis of the current occupancy of the flight levels, operational requirements are defined in terms of altitude segregation. RPAS are not allowed to operate in the most occupied flight levels (FL): from FL300 to FL400. Therefore, depending on their operation and performance characteristics (i.e. ceiling), they will adapt their cruise FL to operate below FL300 or above FL400. The optimal value of performance requirements for same-performance RPAS has been found to be a minimum cruise speed of 390 kts, while for low-performance RPAS this minimum cruise speed is of 280 kts. Additionally, for low-performance RPAS, it is found that the rate of climb of 1,000 fpm results in the best performing case when changes in FL are required.

The results show that the values of the key performance indicators for the base scenario are difficult to reach when RPAS are sharing the airspace. However, the establishment of minimum operational and performance requirements contributes to a significant reduction of the negative impact that the integration of RPAS operations implies.

The development of this methodology and its application to the characteristics of each airspace sector will contribute to the full integration of RPAS in non-segregated airspace. ... Read more

Remotely Piloted Aircraft Systems (RPAS) are becoming more and more popular with an increasing number of companies using them in the fields of precision agriculture, emergency delivery of medical aid and preventive maintenance. Trials are being made to extend their use to public safety, monitoring traffic, providing internet and even air taxi services. These RPAS operations are currently handled on a case-by-case basis and operated in segregated airspace by creating temporary restricted areas for other traffic. With the SESAR Joint Undertaking (SJU) estimating that in the next 30 years 20% of the traffic will be remotely piloted, the option of airspace segregation will no longer be feasible. Therefore, integrating RPAS with current manned operations will be required. In doing so, however, the current levels of safety and efficiency should not be compromised. The command and control link (C2), which connects the remotely piloted aircraft and the remote pilot station, plays a pivotal role in the controllability of the aircraft, ATC communication and conflict detection and avoidance systems (CD&A). This project, which is conducted between Delft University of Technology and EUROCONTROL, aims at establishing a methodology of determining how different percentages of flights that are remotely piloted and different C2 link failure rates influence the number of separation losses (blind encounters). For this, fast time simulations of a 24-hour period of the Dutch airspace are performed in AirTOp. This study will contribute to the integration of RPAS in non-segregated airspace and will serve as an input for the regulatory bodies which are yet to set performance standards on RPAS, particularly the C2 link. Replacing between 10 - 50% of the flights in the Dutch airspace by RPAS with failure rates of the C2 link of 0.01 - 0.001 resulted in 1 - 15 flights being replaced by an RPAS with C2 link failure. This generated an additional number of blind encounters between 1.8 - 23.6, or an increase of 0.09 - 1.18% compared to the baseline situation (same traffic, no RPAS). Also, a linear relationship was found between the number of RPAS experiencing a failure of the C2 link and the number of blind encounters. The project also investigates how an RPAS that experiences a failure of the C2 link right at the moment when it enters an ATC sector in Langen FIR (EDGGPHHM) penalizes key ATM performance indicators. The considered KPIs are: number of potential conflicts, air traffic controller task load, sector occupancy, distance flown, flight time, fuel consumption and altitude deviation. The scope is limited to en-route operations above 500 ft and the contingency strategy followed by the RPAS once it loses the C2 link is to proceed to its destination along its originally submitted flight plan. At the same time, air traffic controllers would enforce a separation bubble around the RPAS, such that a buffer is created for the situations in which the remotely piloted aircraft might deviate from it route or behave erratically. Two RPAS performance models are considered: MQ-9 Reaper, a turboprop with a lower cruise speed and climb/descent performance than current civil aircraft and RQ-4A Global Hawk, a turbofan with a cruise speed close to that of civil aircraft and a rate of climb slightly higher. The results of the Monte Carlo tests are analyzed using ANOVA and MANOVA tests. Increasing the size of the separation bubble around the RPAS with C2 link failure by 20%, 40% and 60% resulted in an increase in the number of potential conflicts of 8.3%, 9.2% and 12.0% when a MQ-9 was used. The impact on controller task load was found to be small (increase of 0.4%) and not affected by the size of the separation bubble. Similarly the other KPIs were not affected by a separation increases of up to 60%. Switching 10-30% of the flights to RPAS and using even larger sizes of the separation bubble (twice or three times as large as the minimum ICAO standards) increased the number of potential conflicts by up to 72.9%, sector occupancy by 11.2% and the additional time spent in the sector by 1.4%. Based on the separation requirements which will be enforced around RPAS, the methodology used in the report can be used to assess the impact of experiencing a C2 link loss on the ATM environment. ... Read more

Airports around the world continue to face issues related to the environmental impact of aviation. Mitigation measures have therefore been implemented at many of these airports. Attaining an optimal combination of these mitigation measures is a complex process and because of these complexities, this process does not always result in the most efficient solution in terms of environmental impact.
It is expected that some of the inefficiencies of mitigation measures can be eliminated by using a process that is based on three main principles: to use mathematical optimisation in order to select the best mitigation options, to evaluate multiple performance areas simultaneously, and to evaluate multiple mitigation options at multiple levels of aggregation simultaneously. These three principles have therefore been implemented as capabilities in an integrated decision support system, to determine whether such a system could help improve the airport environmental management process.
Based on the results obtained with the developed support system, the benefits resulting from each of the three capabilities are demonstrated. But ultimately, it is shown that especially the combination of these three capabilities, integrated into a single support system, contributes to improving the airport environmental management process. ... Read more