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Item type:Publication, Access status: without files , Wind-optimal ats route redesign: A methodology and its application to route a461 in china(2016-06); ; ; ; Due to airspace restrictions and limited availability of navigational aids, ideal direct Air Traffic Services (ATS) routes are usually difficult to achieve in real operations. Moreover, aviation is a fast growing industrial sector causing congestion of the airspace. Hence, in order to improve the flight efficiency and approximate the optimal performance, the redesign and optimization of the ATS route network is required. Route optimization on a tactical level taking into account wind, as one of the most influencing factors, has been broadly discussed in the literature. In contrast, here we present a methodology, which aims at redesigning ATS routes on a strategic level, considering wind situations of a whole year. To achieve this, the average air distance, e.g. the distance corrected by wind effects, along the route has to be minimized. The methodology is then applied to a segment of the Chinese ATS route A461. Since there are several different aircraft types operating on this route, the fleet mix is analyzed to determine typical cruise flight conditions on that route. For the optimization, graph theory based techniques are applied in which a high resolution graph is modeled as search space for the optimization. Assuming mean altitude and mean cruise speed, the air distances between all nodes of the graph are computed for every day of the year 2014 based on wind data from the ECMWF. The air distances of each connections are then averaged and used as cost function within a Dijkstra Algorithm, which is applied in order to obtain annually and quarterly optimized routes. Subsequently, the efficiency increase of the resulting tracks is compared to the theoretical average potential of a tactical daily-based route optimization scenario. Furthermore it is examined, whether the obtained tracks optimizing the year 2014 would have offered efficiency increases for the years 2012 and 2013 as well, in order to estimate a possible long-term feasibility. Finally, an analysis of the tracks in the terms of flight performance is carried out to quantify possible fuel savings.Publicationtype: Conference Paper81 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Cost-benefit assessment of 2D and 3D climate and weather optimized trajectoriesClimate optimized flight trajectories are considered to be a promising measure to mitigate non-CO2 emissions’ environmental impact, which is highly sensitive to locus and time of emission. Within this study, optimal control techniques are applied in order to determine 2D (lateral) and 3D (lateral and vertical) cost-optimized flight trajectories while mitigating their climate impact by minimizing emissions and flight time in highly climate sensitive regions. Therefore, monetary and 4D-climate cost functions, describing the climate sensitivity in dependency of the emission location, altitude, time and weather situation, are integrated into the optimization algorithm. For both, 2D- and 3D-optimization, the cost-benefit potential (climate impact mitigation vs. rise in operating costs) is investigated for nine fictitious North Atlantic routes for eastbound and westbound directions in the presence of winds. The conducted study shows large potential for both measures as the reduction of climate sensitivities along the trajectory often predominates the additional emissions caused by headwinds, additional climb-and descent phases, additional flight distance, and off-design altitudes. Flight trajectories optimized within the horizontal plane can reduce the average temperature response (ATR) by approximately 15 % for a two percent increase in cash operating costs (COC). This mitigation potential is significantly improved by superposition of lateral and vertical optimization. 3D-optimized trajectories which are comparable in cost increase achieve a 20-35 % higher ATR reduction than their 2D-optimized counterparts. Further, they reduce global warming more efficiently (higher ATR reduction per unit cost increment) and to a higher extent. However, achieving maximum climate impact mitigation is linked with an disproportional rise of cash operating costs in both cases. Therefore, a careful consideration of the required climate impact savings as well as the accepted surcharges is necessary.Publicationtype: Conference Paper87 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Are climate restricted areas a viable interim climate mitigation option over the north atlantic?In order to achieve global environmental goals like the 2-degree-target, as well as to reduce longer-term emission levels, mitigation measures have to be introduced, preferably as early as possible. In aviation, the implementation of the most promising mitigation strategies, e.g. climate optimized routing, is linked with several technical challenges. An early introduction of interim mitigation strategies, which bridges the time period until most auspicious approaches reach market maturity, may pave the way for a prompt reduction of aviation’s induced global warming. Within this study, climate restricted airspaces (CRA) are defined in analogy to military exclusion zones. Climate cost functions (CCF) characterize the environmental impact caused by an aircraft emission at a certain location and time. To estimate the monthly climate sensitivity of an area, CCFs are derived with the climate-response model AirClim. Within this study, we close regions with climate sensitivities greater than a threshold value for a period of time (e.g. a month) and affected flight trajectories are re-routed cost optimally around them. The evaluation of the climate impact mitigation potential of climate restricted areas is performed based on optimal control techniques. Monetary costs are integrated into the cost functional of the Trajectory Optimization Module (TOM). Further, high penalties are introduced within restricted airspaces in order to ensure the avoidance of CRA. The cost-benefit potential (climate impact mitigation vs. rise in operating costs) for this interim mitigation concept is investigated for varying threshold values for the closure of airspace and compared with climate optimized trajectories (COT) for different routes and seasons of the year.Publicationtype: Conference Paper56