Airspace Users Research Articles

Learning With Confidence the Likelihood of Flight Diversion Due to Adverse Weather at Destination

When an aircraft is unable to land at its original destination airport, it is diverted to an alternate airport. This event has economic and operational implications for airspace users and airports, as well as negative environmental consequences. Diversions are triggered by many reasons, including adverse weather (e.g., low visibility) or medical emergencies. While the latter are certainly unpredictable, the former could be learned from observed diversions, given the weather at the estimated time of arrival and the landing capabilities of the aircraft and airport. Unfortunately, only airspace users are aware of the reason for the observed diversions. This implies that some (unknown) diversion in the historical data should not be learned by the model because they were triggered by reasons different from adverse weather. This paper presents a gradient boosted decision trees model that learned the likelihood of diversions due to adverse weather from noisy labels using confident learning. Results indicate that this method is effective in pruning of diversions caused by reasons other than adverse weather, and that diversions could be predicted with high precision and moderate recall.

A Comparison of Airport Risks: Unmanned Aircraft Systems (UAS) Sightings, Wildlife Strikes, and Runway Incursions

To provide a context for the potential threat of unmanned aircraft systems (UAS) sightings on airport operations, this paper compares the characteristics of UAS sightings with two common airport threats: wildlife strikes and runway incursions. This study analyzed over 60,000 events in a three-year period (September 2016 to August 2019), including 6,551 UAS sightings from the Federal Aviation Administration (FAA) UAS Sightings Report database, 47,574 wildlife strikes from the FAA Wildlife Strike database, and 6,041 runway incursions from the FAA Runway Safety database. The results suggest both similarities and differences among the airport threats. Both UAS sightings and wildlife strikes vary by time of year and time of day. UAS sightings and wildlife strikes farther from the airport occur at higher altitudes than sightings and strikes occurring close to the airport. However, UAS sightings are reported at higher altitudes than wildlife strikes, and the distance of UAS sightings from the airport is farther than that of wildlife strikes, in general. The severities of UAS sightings and runway incursions are similar. Pilots take evasive actions in three percent of UAS sightings, and runway incursions of severity A and B are also rare. Pilots of general aviation (GA) aircraft reported the most UAS sightings, and GA operations are also involved in more runway incursions. Considering the kind of airport affected, UAS sightings and wildlife strikes are more common at primary airports, notably large and medium hub airports, whereas runway incursions are more common at reliever airports. Generally, UAS have had a minimal impact on airport operations despite their growing prevalence, which reflects the overall success of integrating this new airspace user into the national airspace system.

DATA MANAGEMENT FROM MOBILE METEOROLOGICAL STATIONS FOR GENERAL AVIATION AND STATE INTEGRATED RESCUE SYSTEM

The article deals with the problem of obtaining objective meteorological information for general aviation, which also includes the aviation component of the Integrated Rescue System of the Slovak Republic. The article aims to present a possible solution to the insufficient meteorological coverage of various parts of Slovakia, which would be inexpensive, and easy to install, with the possibility of subsequent sharing of data for the needs of the decision-making process in the environment of crisis management in emergencies, and at the same time would provide relevant data in normal aviation practice. The article identifies the specific needs of general aviation meteorological assurance based on the prevailing mode of flying in this segment of aviation. Based on this analysis, the article's authors describe the meteorological system used for educational purposes at the Aviation Faculty of the Technical University in Košice and propose a system for processing and further managing meteorological data obtained from this type of meteorological station. At the same time, the article mentions data-flow management, which ensures the sharing of data with other airspace users, which adds socio-economic benefits to the entire system in the form of increasing the level of flight safety and more efficient planning of flight routes. The article also deals with the case of providing crisis management, and metrological information from critical places, namely the operational deployment of mobile meteorological devices in areas with a declared emergency.

A survey on security and privacy issues of UAVs

In the 21st century, the industry of drones, also known as Unmanned Aerial Vehicles (UAVs), has witnessed a rapid increase with its large number of airspace users. The tremendous benefits of this technology in civilian applications such as hostage rescue and parcel delivery will integrate smart cities in the future. Nowadays, the affordability of commercial drones expands their usage on a large scale. However, the development of drone technology is associated with vulnerabilities and threats due to the lack of efficient security implementations. Moreover, the complexity of UAVs in software and hardware triggers potential security and privacy issues. Thus, posing significant challenges for the industry, academia, and governments.In this paper, we extensively survey the security and privacy issues of UAVs by providing a systematic classification at four levels: Hardware-level, Software-level, Communication-level, and Sensor-level. In particular, for each level, we thoroughly investigate (1) common vulnerabilities affecting UAVs for potential attacks from malicious actors, (2) existing threats that are jeopardizing the civilian application of UAVs, (3) active and passive attacks performed by the adversaries to compromise the security and privacy of UAVs, (4) possible countermeasures and mitigation techniques to protect UAVs from such malicious activities. In addition, we summarize the takeaways that highlight lessons learned about UAVs’ security and privacy issues. Finally, we conclude our survey by presenting the critical pitfalls and suggesting promising future research directions for security and privacy of UAVs.

ATC Human Factors Involved in RPAS Contingency Management in Non-Segregated Airspace

Objectives: The overall approach towards Remotely Piloted Aerial System integration into a non-segregated airspace is that the unmanned vehicles should be able to fit into the current air traffic management system, thus meeting all the technical and regulatory requirements to be treated similar to any other airspace user. Such a requirement implies that unmanned aircraft operations should behave as close as possible to manned aviation or at least generate the most negligible possible negative impact on the system. From the air traffic management point of view, this implies that air traffic controllers should be capable of effectively handling different types of RPAS operating in a nominal state but also when suffering a potential contingency. This paper aims to analyse how air traffic controllers involved in managing unmanned aircraft integration into non-segregated airspace are impacted when an unmanned vehicle suffers a contingency. Participants: Six air traffic controllers were the test subjects, complemented by one RPAS pilot and several pseudo-pilots controlling the simulated manned traffic. The project collected real-time simulation data to develop specific indicators to determine how the controllers’ workload increases while managing complex traffic scenarios, including a single RPAS. Study Method: We conducted exhaustive traffic flight simulations, recreating complex airspace scenarios, including various RPAS types and mission-oriented trajectories. The involved RPAS were subjected to two of the most relevant contingencies: loss of the command-and-control link and engine failure. The experiments were evaluated in different operational scenarios, including using autonomous communication technologies to help air traffic controllers track the RPAS operation. Findings: The results indicate that the air traffic controller’s perception and workload are not affected beyond reason by the introduction of an unmanned aircraft as a new element into the non-segregated airspace, even when that aircraft suffers a contingency. The flight-intent technology increases situational awareness, leading to more efficient and safe airspace management. Additional simulations may need to be performed to evaluate the impact on airspace capacity, safety, and workload when various unmanned vehicles are simultaneously inserted.

Technological Setup for UAM Tactical Instrumental De-confliction and in-Flight Resolution demonstration in real environment: A case Study

Urban Air Mobility (UAM) refers to the provision of mobility services in an urban environment using air vehicles. As this important and growing domain evolves, it is clear that new operational concepts, regulations and standards will be needed, underpinned by existing and new technologies. The whole environment will need to integrate safely with manned aviation and air traffic control. This paper discusses the design of demonstration activities within the TINDAiR project (Tactical Instrumental De-confliction And in-flight Resolution), which is performing the demonstration of four UAM use cases in real environment, aimed to deliver strategic and innovative technologies that can drive competitiveness and UAM growth using an impact-oriented approach and to demonstrate the safe integration of UAM vehicles as additional airspace users.

Design of a collector for sampling volcanic ash using unmanned aerial systems

Volcanic ash is an aerial hazard to both aircraft and local populations, hence efforts to monitor and quantify its presence are underway in many regions, both to protect airspace users and as a modeling tool for volcanology. One direct approach is to acquire in-situ ash samples using an unmanned vehicle, but this introduces possible bias in the samples due to the collector system, especially across the full range of ash particle sizes. This work explores an open impact type design of miniaturized airborne ash collector and quantifies the influence of the collector geometry on the measured particle size distribution. Results indicate that the distribution of sizes measured can be strongly influenced by the collector design, owing to the influence of the geometry on the aerodynamics and hence the particle trajectories. Comparisons to experimental flight data illustrate that the simulations provide a representative model, and that a design featuring a bluff fore-body separates and mixes the flow, making it more capable of capturing small particles than a planar surface in isolation.

Flight Training Syllabus Structure Impact on Proactive Planning of High-Performance Military Aircraft Pilot Training Operations in Flexible Airspace Structures

European airspace is marked by fragmentation, and from fragmentation originated congestion. As an answer to congestion, flexible use of airspace is created to fulfil all users’ requirements optimally, and at its very core lies civil-military cooperation and the coordination of airspace use. Such an approach is enabled by collaborative decision-making, which presumes timely and complete exchange of complete relevant information between airspace users. To participate in the process, the military should be transparent regarding its restrictions and capabilities of adaptation to other airspace users’ demands. Flight training syllabus structure and its specific impact on proactive planning of high-performance military aircraft pilot training operations in flexible airspace structures is the subject of this research. Significant diversity in the hourly distribution of civil traffic demand in flexible airspace structures in Zagreb FIR proves them applicable for a proactive approach to high-performance aircraft pilot training operations planning and management. Noticeable reduction in the number of civil aircraft affected by high-performance aircraft pilot training operations in flexible airspace structures at congested flight levels is corroborated. Simulations of proactive planning of high-performance aircraft pilot training operations reveal indications of flight syllabus structure’s impact on pilot flight training duration, as well as the possibility to manage its restrictions.

From Single Aircraft to Communities: A Neutral Interpretation of Air Traffic Complexity Dynamics

At present, decision-making in ATM is fragmented between different stakeholders who have different objectives. This fragmentation, in unison with competing KPAs, leads to complex interdependencies between performance indicators, which results in an imbalance, with some of these indicators being penalized to the apparent benefit of others. Therefore, it is necessary to support ATM stakeholders in systematically uncovering hidden trade-offs between KPAs. Existing literature confirms this claim, but how to solve it has not been fully addressed. In this paper, we envision air traffic complexity to be the framework through which a common understanding among stakeholders is enhanced. We introduce the concept of single aircraft complexity to determine the contribution of each aircraft to the overall complexity of air traffic. Furthermore, we describe a methodology extending this concept to define complex communities, which are groups of interdependent aircraft that contribute the majority of the complexity in a certain airspace. Through use-cases based on synthetic and real historical traffic, we first show that the algorithm can serve to formalize and improve decision-making. Further, we illustrates how the provided information can be used to increase transparency of the decision makers towards different airspace users. In order to showcase the methodology, we develop a tool that visualizes different outputs of the algorithm. Lastly, we conduct sensitivity analysis in order to systematically analyse how each input affects the methodology.

Predicting the likelihood of airspace user rerouting to mitigate air traffic flow management delay

At present, the most common air traffic flow management measure used by the European Network Manager to solve en-route demand and capacity balance issues is to impose air traffic flow management regulations in congested airspace, which delay flights on the ground to smooth demand. The delay imposed on a regulated flight, however, has a negative operational and economic impact on the corresponding airspace user. When the impact is severe, the airspace user may reroute the flight to tactically circumvent the regulated airspace, thereby avoiding the regulation and reducing (or even eliminating) the delay. This legitimate strategy is unquestionably effective in mitigating the delay and the associated cost, but it may also increases traffic demand uncertainty due to last-minute changes as well as the environmental impact due to sub-optimal trajectories. This paper presents a gradient-boosted decision trees model that, trained on historical data, could assist in predicting the likelihood of a regulated flight rerouting to mitigate air traffic flow management delay. Specific metrics for highly imbalanced binary classification problems reveal that, while not perfect, the model outperforms a rudimentary decision tree and a dummy classifier. Furthermore, Shapley values computed with the model uncover the most important triggers for tactical rerouting from a data-driven perspective, namely the current delay, the aircraft operator, the airspace sector where the most penalising regulation is applied and the remaining time until departure. This interpretable model could be used to assist flow managers in their decision-making, as well as to accurately mimic the behaviour of flight dispatchers when facing delays in simulators.

Autonomous planning of optimal four-dimensional trajectory for real-time en-route airspace operation with solution space visualisation

One of the challenges in applying autonomous operation-based conflict detection and resolution (CD&R) techniques to practice is their functional completeness, such as the ability to simultaneously consider three-dimensional (3D) scenarios, controlled time of arrival, restricted areas, trajectory recovery, and multi-stakeholder performance preferences. Besides, the effective interaction between controllers, pilots and autonomous operating system can better support the CD&R to work in practice, where humans are able to intuitively understand the rationale for solutions given by automatic decision-making tools. To bridge the gap, a novel operational framework for four-dimensional (4D) trajectory conflict management in the context of free route airspace is proposed. Airspace discretisation based on a 3D grid is used to facilitate the consideration of restricted areas and to balance calculation speed and optimal effect. The core of this framework is a two-stage real-time autonomous 4D trajectory planning method in a restricted en-route sector with multiple flight levels enhanced by solution space visualisation. Stage one is a trajectory pre-planning model based on a visibility graph and the Dijkstra algorithm considering the conflict between aircraft and emerging restricted areas. Stage two is a real-time conflict-free and fuel-optimal 4D trajectory re-planning model. The space–time prism is employed to enable the planned trajectory to meet the controlled time of arrival and trajectory recovery requirements, where the performance preferences of both the air traffic management and airspace users are taken into account. The reachable solution space representation is applied to realise the solution space visualisation that has the potential to support the human–machine interaction and air–ground coordination. A simulation scenario is established to validate the effectiveness, efficiency, stability, and timeliness of the proposed method. Results show that in an artificial en-route sector, the average extra flight distance, average flight delay, average extra fuel consumption, and average computing time for conflict resolution were less than 0.41 km, 2.1 s, 1.5 kg, and 0.08 s in the saturated scenario, respectively, and the domino effect of the flight conflict did not show a significant rise with the increase of traffic density, which verified that the proposed autonomous trajectory operation methodology is a promising approach to facilitate autonomous air traffic management in the future.

Sharing airspace with Uncrewed Aerial Vehicles (UAVs): Views of the General Aviation (GA) community

Operations of Uncrewed Aerial Vehicles (UAVs or drones) are expanding, leading to competition for airspace with other users such as the General Aviation (GA) community, i.e., sports and leisure airspace users, particularly in uncontrolled airspace. As a result, there is an increasingly urgent need for a shared airspace resolution, whereby drones become integrated harmoniously in unsegregated operations with crewed aircraft, providing equitable airspace access for all. The purpose of the study was to engage with the GA community and elicit concerns and issues regarding the shared airspace concept as an initial step in the co-development of the future form of airspace. The method used was an online, interactive workshop with participants (n ~ 80) recruited from the GA community in the United Kingdom (UK). Data captured (verbal and written) were analysed qualitatively using thematic analysis, producing findings that summarised the issues identified on a range of different topics, grouped together under three over-arching themes: (1) operational environment; (2) technical and regulatory environment; and (3) equity and wider society. Almost a quarter of participants’ comments (27%) were related to the opinion that shared airspace would only be possible if aircraft were fitted with Detect-And-Avoid (DAA) systems for de-confliction, based on onboard Electronic Conspicuity (EC) devices. Findings suggested that airspace management policies that establish equitable regulatory and technology environments regarding shared airspace are needed, and that those policies should be inclusive, having as a key aim the involvement of the GA community (and all other stakeholders) in the development process. The study represents a first step in the involvement of the wider aviation community in the co-design of shared airspace to include drones.

The value of flexible flight-to-route assignments in pre-tactical air traffic management

In European air traffic management, there are discussions regarding the future role of the network manager (NM): in particular, should the NM be able to assign flights to specific trajectories, should airspace users be allowed to freely choose their preferred trajectory, or something in between? In this paper, we develop a modeling framework that can be adapted to these settings to assess their effect on key performance indicators.We focus on the pre-tactical stage of planning air traffic for a future departure day, meaning that airspace capacity budgets are given and incoming flight intentions need to be offered one or several ‘trajectory products’ for a (possibly dynamically determined) charge. These trajectory products differ in the amount of flexibility that they provide the NM to route the flight. Charges are set so as to reward greater flexibility of airspace users with lower charges. The airspace user chooses one of the offered trajectory products according to a choice model that reflects their preferences given, among others, the product charges. Shortly before the departure day, the NM decides simultaneously on the routing (within the limits defined by the purchased trajectory products) and on each airspace’s sector opening scheme (within the limits of the fixed capacity budgets) so as to minimize the overall displacement cost. Methodologically, the problem deviates from typical dynamic pricing problems in various major ways, e.g., featuring a boundary condition that we show to be NP-hard as well as fairness and revenue neutrality constraints. The problem is cast in the form of a dynamic program. We exploit a certain structure in the boundary condition to formulate an efficient heuristic. Based on a numerical case study, we find that the use of dynamically priced trajectory products achieves a cost performance close to the one obtained if the NM has a mandate to simply assign flights to trajectories. Therefore, this seems an attractive design for the role of the NM, giving airspace users some choice whilst achieving low overall costs.

Feasibility Study of Free Route Airspace over the North Pacific

A fast-time simulation study was conducted to examine the expansion of flexible track operations into the area occupied by the five North Pacific (NOPAC) air traffic service routes, an area of high traffic demand. In this study, user-preferred routes were created in a proposed NOPAC free route airspace (FRA) area, in which airspace users may design routes with few constraints and compared with current fixed NOPAC route structure by fast-time simulation. To reflect the effect of daily and seasonal wind variations, a clustering analysis approach was applied to select representative wind conditions for flight route generation. Fuel burn was used to evaluate the effect of the NOPAC FRA on the efficiency of flight operations, and potential loss of separation (PLOS) was examined for three minimum lateral separations to evaluate the effects of communication, navigation, and surveillance performance on airspace capacity and air traffic control workload. The simulation results show a trend of increased efficiency of individual NOPAC FRA flight routes, with potential mean fuel consumption savings of 849.2 kg for eastbound Alaska flights and 532.4 kg for westbound North America flights compared with current route configurations. Results of PLOS also show reduced overall PLOS time. This indicates that a NOPAC FRA could improve capacity and efficiency while maintaining or increasing safety.

Determination of Way Points Position on Sequencing Leg for Point Merge System

This paper aims to propose a novel approach to determination of way points position on sequencing leg for point merge system. This research uses the Base of Aircraft Data to analyze the flight efficiency. Although it is not a general rule, it can be said that there is a tendency in practice to design the waypoints in the sequencing leg at equal distances from each other. In general, essentially equidistant waypoints are designed to facilitate the adaptation of airspace users (both pilots and air traffic controllers). However, it does not seem possible to say that this tendency always gives the most appropriate and optimal results in terms of flight efficiency. A scenario that includes four different cases was ideated and was resolved to discover the potential benefits and/or drawbacks of equidistant and non-equidistant interspace of waypoints. The comparison results of equidistant and non-equidistant interspace show that the average reduction of 9,5 percent of total flight time; 12,5 percent of total flight distance in favor one of a non-equidistant interspace, which is Case-4. Moreover, the Case-4 could be a promising solution for sequencing aircraft conveniently in terms of a first come first service (FCFS) rule.

AMSS in Europe

Nowadays, technology is developing rapidly, therefore satellite and aviation systems need to keep pace with modern trends and new technology. The paper is focused on satellite systems and aviation systems. Based on analysis of the issues it is possible to take measures against problems that may arise in the future. There is a need for satellite-based navigation system that can solve the problems of the existing systems and make the existing systems better and more efficient by providing great convenience to the airspace users for the safe, efficient, comfortable and economical realisation of flights in the future. The paper contains information about Air Communication and Navigation Systems and discusses the state of current aviation and satellite systems.

Optimizing and Visualizing Dynamic Service Performance for Airspace Users to Enable Safe and Efficient Urban Air Mobility in Dubai

Optimizing and Visualizing Dynamic Service Performance for Airspace Users to Enable Safe and Efficient Urban Air Mobility in Dubai

An agent-based model for air transportation to capture network effects in assessing delay management mechanisms

This article presents some of the results on the implementation of a decentralised delay management process that we call 4D trajectory adjustments (4DTA) obtained with Mercury, a stochastic agent-based model. The model operates within a strong agent paradigm at the level of individual flights and passengers. It includes a realistic cost model for the airlines, allowing us to have a good tactical choice model and excellent estimation of airspace user costs. Due to the inclusion of different stakeholders, including passengers, and various processes – like aircraft turnaround or passenger reaccommodation – it is able to catch European-wide network effects that are inaccessible to other models. It was used to study the 4DTA process, a blend of ‘wait for passengers and tactical speed adjustments’, which is shown to have a significant impact on the system. Thanks to the detailed output of the model, we are able to breakdown the effect for different classes of flights and passengers, and show that important trade-offs exist in terms of delays and costs. In particular, the introduction of such mechanism could be detrimental to non-connecting passengers, especially at secondary airports.

Estimating economic severity of Air Traffic Flow Management regulations

The development of trajectory-based operations and the rolling network operations plan in European air traffic management network implies a move towards more collaborative, strategic flight planning. This opens up the possibility for inclusion of additional information in the collaborative decision-making process. With that in mind, we define the indicator for the economic risk of network elements (e.g., sectors or airports) as the expected costs that the elements impose on airspace users due to Air Traffic Flow Management (ATFM) regulations. The definition of the indicator is based on the analysis of historical ATFM regulations data, that provides an indication of the risk of accruing delay. This risk of delay is translated into a monetary risk for the airspace users, creating the new metric of the economic risk of a given airspace element. We then use some machine learning techniques to find the parameters leading to this economic risk. The metric is accompanied by an indication of the accuracy of the delay–cost prediction model. Lastly, the economic risk is transformed into a qualitative economic severity classification. The economic risks and consequently economic severity can be estimated for different temporal horizons and time periods providing an indicator which can be used by Air Navigation Service Providers to identify areas which might need the implementation of strategic measures (e.g., resectorisation or capacity provision change), and by Airspace Users to consider operation of routes which use specific airspace regions.

The Next Generation Air Transportation System of the United States: Vision, Accomplishments, and Future Directions

Abstract To address concerns about anticipated increases in air traffic, leverage the capabilities of new technologies to enhance service, and accommodate new classes of airspace users, the U.S. Federal Aviation Administration and its partners embarked on a modernization effort known as the Next Generation Air Transportation System, or NextGen. NextGen encompasses a wide-range of improvements in communications, navigation, surveillance, and Air Traffic Management (ATM) automation systems. NextGen also includes many procedural improvements to leverage new technologies and advances in the science of ATM. This article describes the vision for NextGen, discusses the planning framework (including the business case for the investments), enumerates the major implementations to date, and describes the implementation challenges. Finally, the article discusses the future direction of NextGen.