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I.C. Metz

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14 records found

Journal article (2021) - I.C. Metz, J. Ellerbroek, Thorsten Mühlhausen, Dirk Kügler, J.M. Hoekstra
Bird strike prevention in civil aviation has traditionally focused on the airport perimeter. Since the risk of especially damaging bird strikes outside the airport boundaries is rising, this paper investigates the safety potential of operational bird strike prevention involving pilots and controllers. In such a concept, controllers would be equipped with a bird strike advisory system, allowing them to delay departures which are most vulnerable to the consequences of bird strikes in case of high bird strike risk. An initial study has shown the strong potential of the concept to prevent bird strikes in case of perfect bird movement prediction. This paper takes the research to the next level by taking into account the limited predictability of bird tracks. As such, the collision avoidance algorithm is extended to a bird strike risk algorithm. The risk of bird strikes is calculated for birds expected to cross the extended runway center line and to cause aircraft damage upon impact. By specifically targeting these birds and excluding birds lingering on the runway which are taken care of by the local wildlife control, capacity reductions should be limited, and the implementation remain feasible. The extrapolation of bird tracks is performed by simple linear regression based on the bird positions known at the intended take-off times. To calculate the probability of collision, uncertainties resulting from variability in bird velocity and track are included. The study demonstrates the necessity to limit alerts to potentially damaging strikes with birds crossing the extended runway center line to keep the imposed delays tolerable for airports operating at their capacity limits. It is shown that predicting bird movements based on simple linear regression without considering individual bird behavior is insufficient to achieve a safety-effect. Hence, in-depth studies of multi-year bird data to develop bird behavior models and reliable predictions are recommended for future research. This is expected to facilitate the implementation of a bird strike advisory system satisfying both safety and capacity aspects. ...
Journal article (2021) - I.C. Metz, J. Ellerbroek, Thorsten Mühlhausen, Dirk Kügler, Stefan Kern, J.M. Hoekstra
Involving air traffic controllers and pilots into the bird strike prevention process is considered an essential step to increase aviation and avian safety. Prior to implementing operational measures such as real-time warning systems, it is vital to evaluate their feasibility. This paper studies the efficacy of a bird strike advisory system for air traffic control. In addition to the potential safety benefit, the possible impact on airport operations is analyzed. To this end, a previously developed collision avoidance algorithm underlying the system was tested in fast-time Monte Carlo simulations involving various air traffic and bird densities to obtain representative conclusions for different operational conditions. The results demonstrate the strong safety potential of operational bird strike prevention in case of precise bird movement prediction. Unless airports operate close to their capacity limits while bird abundance is high, the induced delays remain tolerable. Prioritization of hazardous strikes involving large individuals as well as flocks of birds are expected to support operational feasibility in all conditions ...
Doctoral thesis (2021) - I.C. Metz
Bird strike prevention in civil aviation has traditionally focused on the airport perimeter. Since the risk of especially damaging bird strikes outside the airport boundaries is rising, this PhD thesis researches the safety potential of operational bird strike prevention involving pilots and controllers. In such a concept, controllers would be equipped with a bird strike advisory system, allowing them to delay departures which are most vulnerable to the consequences of bird strikes. However, the introduction of take-off delays reduces the maximum capacity of a runway. This PhD thesis investigates the feasibility of a bird strike advisory system with regard to safety and capacity by performing fast-time simulations including different air traffic intensities and bird abundance. In a first step, a system assuming perfect predictability of bird movement is developed, demonstrating a strong safety potential. However, when preventing all bird strikes, the induced delays can exceed tolerable limits for high air traffic intensities. In a second step, the system includes the limited predictability of bird movement. Bird tracks are predicted based on a simple linear regression model, considering variability of velocity and heading. To limit the negative effects on runway capacity, delays are only imposed on aircraft, for which strikes are predicted with a high probability and a damaging potential. The number and duration of delays remains reasonable even for airports operating at their capacity limits. However, linear regression proves insufficient to suitably evaluate the risk of collisions. To achieve reliable predictions, in-depth studies of multi-year bird movement data from various sensor types are recommended to develop site- and species-specific bird models. As such, the concept of a bird strike advisory system can be further developed to exploit the entire safety potential demonstrated by the initial study of the thesis. ...
Review (2020) - Isabel C. Metz, Joost Ellerbroek, Thorsten Mühlhausen, Dirk Kügler, Jacco M. Hoekstra
Collisions between birds and aircraft pose a severe threat to aviation and avian safety. To understand and prevent these bird strikes, knowledge about the factors leading to these bird strikes is vital. However, even though it is a global issue, data availability strongly varies and is difficult to put into a global picture. This paper aims to close this gap by providing an in-depth review of studies and statistics to obtain a concise overview of the bird strike problem in commercial aviation on an international level. The paper illustrates the factors contributing to the occurrence and the potential consequences in terms of effect on flight and damage. This is followed by a presentation of the risk-reducing measures currently in place as well as their limitations. The paper closes with an insight into current research investigating novel methods to prevent bird strikes. ...
Conference paper (2019) - Isabel C. Metz, Thorsten Mühlhausen, Joost Ellerbroek, Dirk Kügler, Jacco M. Hoekstra
This paper presents a collision avoidance algorithm to prevent bird strikes for aircraft departing from an airport. By using trajectory-information of aircraft and birds, the algorithm predicts potential collisions. Collision avoidance is performed by delaying departing aircraft until they can follow a collision-free trajectory. An implementation of this concept has the potential to increase aviation safety by preventing bird strikes but might reduce runway capacity due to delaying aircraft. As a precursor to the feasibility, this study investigates the maximum achievable safety effect at minimum delay costs of such a system by assuming a deterministic world. Therefore, no uncertainties regarding bird and aircraft positions were considered to enable the system to prevent all bird strikes for departing traffic while causing the smallest possible delay. The anticipated effects were studied by running fast-time simulations including three air traffic intensities at a single-runway airport and bird movements from all seasons. The results imply a high potential for the increase in safety at a reasonable reduction in runway capacity. An initial cost-estimate even revealed a strong saving potential for the airlines. Based on these results, a feasibility study of implementing a bird strike advisory system including uncertainties in bird movements as well as probabilistic effects will be performed. ...
Abstract (2018) - Isabel Metz, Thorsten Muhlhausen, Joost Ellerbroek, Jacco Hoekstra
Bird strikes have the potential to cause severe damage to aircraft. Therefore, measures to reduce the risk of bird strikes are performed at airports. However, this risk is not limited to the airport but is increased in the arrival and departure corridors as well. Consequently, a significant amount of bird strikes occurs outside the direct airport area. To estimate the risk of bird strikes in this extended airport area, a fast-time simulation environment was developed, representing air traffic as well as bird movement. It was verified by performing Monte-Carlo Simulations including real flight plans, a model for realistic bird movements and a comparison to real bird strike data. In this study, the simulation results were evaluated considering the impact of bird strikes. For this purpose, the kinetic energy of the bird strikes that occurred within the simulation was calculated. Based on the international certification requirements for the impact resistance of engines, windshields and structure, the potential for severe damage was analysed. Finally, the results were compared to a long-term study of damaging bird strikes of the US aviation authorities. The results indicate that the simulation environment allows a reasonable estimation of the damaging potential of bird strikes. The simulation data derives from the Netherlands, while the real bird strike data originates from the US. For further validation and enhancement of the simulation’s bird model, European data from multiple years would be required. ...

Early warning systems in Europe and the Middle East prevent collisions between birds and aircraft

Journal article (2018) - Hans van Gasteren, Karen L. Krijgsveld, Nadine Klauke, Yossi Leshem, Isabel Metz, Micha Skakuj, Serge Sorbi, Inbal Schekler, Judy Shamoun‐Baranes
The aerosphere is utilized by billions of birds, moving for different reasons and from short to great distances spanning tens of thousands of kilometres. The aerosphere, however, is also utilized by aviation which leads to increasing conflicts in and around airfields as well as en‐route. Collisions between birds and aircraft cost billions of euros annually and, in some cases, result in the loss of human lives. Simultaneously, aviation has diverse negative impacts on wildlife. During avian migration, due to the sheer numbers of birds in the air, the risk of bird strikes becomes particularly acute for low‐flying aircraft, especially during military training flights. Over the last few decades, air forces across Europe and the Middle East have been developing solutions that integrate ecological research and aviation policy to reduce mutual negative interactions between birds and aircraft. In this paper we 1) provide a brief overview of the systems currently used in military aviation to monitor bird migration movements in the aerosphere, 2) provide a brief overview of the impact of bird strikes on military low‐level operations, and 3) estimate the effectiveness of migration monitoring systems in bird strike avoidance. We compare systems from the Netherlands, Belgium, Germany, Poland and Israel, which are all areas that Palearctic migrants cross twice a year in huge numbers. We show that the en‐route bird strikes have decreased considerably in countries where avoidance systems have been implemented, and that consequently bird strikes are on average 45% less frequent in countries with implemented avoidance systems in place. We conclude by showing the roles of operational weather radar networks, forecast models and international and interdisciplinary collaboration to create safer skies for aviation and birds. ...
Journal article (2018) - Isabel Metz, Thorsten Muhlhausen, Joost Ellerbroek, Dirk Kügler, Hans van Gasteren, Jan Kraemer, Jacco Hoekstra
Annually, thousands of birds collide with aircraft. The impact usually has lethal
consequences for the bird, the involved aircraft can experience severe damage. The highest bird strike risk occurs at low altitudes. Therefore, aircraft within the airport area as well as the adjacent approach and departure corridors are especially vulnerable to collisions with birds. To analyse risk-reducing measures in these areas, a fast-time bird strike simulation environment was developed. An open-source Air Traffic Management simulator was enhanced with a model to represent bird movements and to recognize bird strikes. To confirm the reproducibility of the outcome, Monte Carlo simulations were performed. They included bird movement data from one year and air traffic flight plans for various air traffic volumes. The number of strikes and near misses showed an expected variance within the individual replications. The results indicate that the predictability of the number of strikes and near misses increases with rising number of birds, and rising air traffic intensity. Thus, by considering simulation scenarios including bird movement information from all seasons and a sufficient air traffic volume, the described set-up leads to stable results. ...
Conference paper (2017) - Isabel Metz, Joost Ellerbroek, Thorsten Muhlhausen, D. Kügler, Jacco Hoekstra
This paper presents a fast-time simulation environment for assessing the risk of bird strikes in aviation. An existing air traffic simulator was enhanced in order to simulate air and bird traffic simultaneously and to recognize collisions between birds and aircraft. Furthermore, a method was developed to generate bird movement information from different radar sources. The resulting set-up represents the first simulation environment to perform fast-time simulations including air traffic and bird movements. A verification with real data revealed that approximately thrice as many bird strikes occur in the simulation as in reality. When considering bird reaction to approaching aircraft, which is not covered in the simulation as well as unreported strikes, this implies an adequate result. For this reason, the simulator can serve as valuable tool to analyse the risk of bird strikes and to evaluate new Air Traffic Management concepts to reduce the number of these events. ...
Abstract (2017) - Isabel Metz, Thorsten Muhlhausen, Joost Ellerbroek, Jacco Hoekstra, D. Kügler
The presented research evaluates the concept of providing an airport’s Air Traffic Control with a bird strike advisory system. Such a system informs the controller about current and predicted bird movements in the arrival and departure corridors. Based on this information, the controller can decide to delay or reroute air traffic in order to prevent collisions with birds. To evaluate the resulting effects on the airport’s safety and capacity, fast-time simulations merging air traffic and bird movements, will be performed. To represent realistic bird movements, inputs from two different radar types are combined. For the close airport environment, historic bird tracks from avian radar installed at the considered airport serve as source. To cover the arrival and departure corridors up to 3000ft, the altitude up to which the largest majority of bird strikes occur, data from weather radar is used: based on bird densities and speed directions, bird tracks are generated for different altitude bands. The obtained tracks from avian and weather radar are combined in order to retrieve the overall image of bird movements in the close and extended airport area. This paper describes the methods for extracting, generating and finally combining the inputs from the two radar sources, in order to generate realistic bird movements. These will serve as a key input parameter for evaluating the effects of a bird strike advisory system with fast-time simulations. ...
Poster (2016) - Isabel Metz, Joost Ellerbroek, T Mühlhausen, D. Kügler, Jacco Hoekstra
Conference paper (2016) - Isabel Metz, M. Freese, T. Pett, S. Schier
The calibration of Angular Accelerometers requires a controlled test with a known accel- eration pro_le. However, current turn-tables have been designed primarily for generating a constant rotational velocity. To generate a pro_le with varying angular acceleration we propose using constant rotational velocity on the two axes of a 2-axes motion simulator. The proposed sequence was developed to obtain the required rotational acceleration signal quality using only rotational velocity input. The identi_ed pattern is applied to an enve- lope of test conditions, resulting in test matrix. This method provides an alternative means to generate inputs that can be used to calibrate angular accelerometers using calibration hardware that is not primarily designed to provide accurate acceleration inputs. ...
Conference paper (2016) - Isabel Metz, Jacco Hoekstra, Joost Ellerbroek, D. Kugler
The BlueSky Open Air Tra_c Simulator developed by the Control & Simulation section of TU Delft aims at supporting research for analysing Air Tra_c Management concepts by providing an open source simulation platform. The goal of this study was to complement BlueSky with aircraft performance models in order to enable performance- related Air Tra_c Management studies. The aircraft performance model developed within this work consists of a kinetic Flight Dynamics Model, which stores the required performance characteristics in a database with type-speci_c aircraft and engine coe_- cients. Currently, sixteen commercial turbofan and turboprop aircraft from di_erent range and weight categories are represented. To evaluate the quality of the aircraft per- formance model, its outputs were compared to results from literature as well as from real ights. It was found that the applied methodologies for the determination of air- craft performance accurately model high-speed drag polars as well as fuel consumption for cruising and taxiing aircraft. The fuel consumption model of climbing and descend- ing aircraft, however, leaves room for improvement. Possible strategies for obtaining a more precise estimation of fuel burn over the entire ight are recommended based on the results of this study. With this work, the BlueSky Open Air Tra_c Simulator considers individual aircraft performance. This is an important step in the creation of an open simulation platform for Air Tra_c Management research. ...
Conference paper (2016) - Isabel Metz, T Mühlhausen, Joost Ellerbroek, Jacco Hoekstra
Bird strikes have operational impacts and cause economic loss to the aviation industry. In the worst case, the damages resulting from bird strikes lead to crashes. The highest risk for bird strikes lies in the area below 3000 ft and thus mainly in airport environments. Despite intense efforts from the airports in controlling the local bird populations, the number of bird strikes in these environments is still very high. Usually, Air Traffic Control is neither integrated into the process for reducing bird strikes nor do the controllers receive any specific information about the current bird traffic situation at the airport. For the project described in this paper, we assume a different situation: Air Traffic Control is provided with a tool supporting the controller with advisories to prevent bird strikes. The advisories are based on the current and predicted bird movements and the anticipated risk for air traffic. Potential advisories include rerouting or delaying of traffic. Especially when applying the latter, a reduced runway capacity could result. However, the effects of a bird strike advisory systems for Air Traffic Control have never been studied. The project in this paper therefore aims at investigating the consequences on an airport's safety and capacity when implementing such a system. For this purpose, fast-time simulations including varying conditions considering bird densities and air traffic volume will be performed. This paper describes the proposed research concept and the chosen simulation environment. ...