Low Visibility: The Fate of Air Traffic Control Privatization

This paper assesses plans to create an independent air traffic control corporation. While the plans being considered don't seem to offer the benefits that could result from privatization (the possible downsides are not being noted here), they also do not offer obvious resolutions to the problems currently faced by the air traffic control system. Since the specifics of a proposal are not currently available, it is not possible to provide a comprehensive assessment of its merits. However, any such proposal will not offer many of the benefits often claimed by advocates of privatization. There also do not appear to be any obvious fixes to the problems faced by the current system as a result of going the route of limited privatization.Notwithstanding a creditable safety record, the Federal Aviation Administration is under fire for mismanagement, particularly in the field of technology modernization. The airline trade association "Airlines for America" ("A4A") and its member carriers are calling for separation of the FAA's air traffic control ("ATC") operations into some kind of independent corporation.The chairman of the Committee on Transportation and Infrastructure of the U.S. House of Representatives, Rep. Bill Shuster (R-PA), has announced his intention to offer a plan resting on some questionable principles, to be discussed below.The appeals for reform typically reflect a yearning for system improvement, a lack of specifics, and a dearth of supporting arguments or data. Dorothy Robyn (2015) of the Brookings Institution noted that "a jaw-droppingly flawed variant on corporatization" has attracted support.It is possible a new air navigation service provider ("ANSP") could provide better service at reduced cost, but thus far no evidence for such a reform in the U.S. has been put forward, nor has any detailed plan been proposed

Key Human-Centered Transition Issues for Future Oceanic Air Traffic Control Systems

Communication, navigation, surveillance, and decision support capabilities in Oceanic air traffic control are evolving significantly. It is important to consider the effect of the changes on the controller’s task. In this paper the results from multi-disciplinary studies performed at MIT (Massachusetts Institute of Technology) and the University of Iceland are presented. At MIT, a human-centered systems analysis was used to identify key human factors issues for the future Oceanic air traffic control environment to be experimentally investigated. At the University of Iceland, a prototype for a future air traffic control display was designed and evaluated. Both studies identified three key human factors issues that require consideration. The first is a mismatch between time and space separation restrictions imposed and information support provided, requiring the controller to cognitively resolve temporal/spatial mismatches to meet restrictions. The second issue is the effects of mixed communication and surveillance equipage, which complicates the control task and requires the controller to cognitively integrate asynchronous information. The final is the importance of cultivating controller trust and understanding issues of complacency and automation disuse when implementing highly automated conflict probes that are being considered in the future Oceanic environments

Water facilities in retrospect and prospect: An illuminating tool for vehicle design

Water facilities play a fundamental role in the design of air, ground, and marine vehicles by providing a qualitative, and sometimes quantitative, description of complex flow phenomena. Water tunnels, channels, and tow tanks used as flow-diagnostic tools have experienced a renaissance in recent years in response to the increased complexity of designs suitable for advanced technology vehicles. These vehicles are frequently characterized by large regions of steady and unsteady three-dimensional flow separation and ensuing vortical flows. The visualization and interpretation of the complicated fluid motions about isolated vehicle components and complete configurations in a time and cost effective manner in hydrodynamic test facilities is a key element in the development of flow control concepts, and, hence, improved vehicle designs. A historical perspective of the role of water facilities in the vehicle design process is presented. The application of water facilities to specific aerodynamic and hydrodynamic flow problems is discussed, and the strengths and limitations of these important experimental tools are emphasized

A screening assessment of dissolved air flotation for control of nonindigenous invasive species transported in shipping ballast water

Uncontrolled discharge of ballast water by vessels has been considered one of the main mechanisms for the introduction of aquatic nuisance species (ANS). The typical size of species found ranges from 0.02 to 10,000 micrometer. This wide range of sizes consists of microorganism (protozoa, dinoflagellates, and cholera), planktonic species, plants, insects, other arthropods, worms, mollusks, and vertebrates. These species either remain suspended in ballast water or settle in ballast tank sediments. Providing treatment for ballast water is a challenging task due to space availability of ships and significant magnitude of flow rates and volumes of ballast water. Currently, open ocean ballast water exchange (BWE) is utilized for control of ANS. However, BWE has potential safety risk and it is not fully effective as a separation method for ANS. This thesis examines common ballast water control methods having potential for shore and vessel-based applications. In addition to BWE, other control methods including dissolved air flotation (DAF) are under consideration. Each control method is examined according to effectiveness, safety, capital and maintenance cost, and applicability. In addition, a screening assessment of DAF as a potential ANS separation technology is being investigated. Experimental bench-scale development of dissolved air flotation was selected and examined to evaluate the potential of DAF as a viable option for ballast water control. Freshwater (1 ppt) and saltwater (20 ppt) matrices were used with ballast water surrogates synthesized from aquaculture, fresh water, wastewater, and storm water. The samples were standardized to a similar turbidity range before application of DAF treatment. Bench-scale experimental results for ballast water surrogates based on particle number demonstrated particle removal efficiencies achieved as high as 99% and 98% for saltwater and freshwater matrix, respectively. Particle size distributions in DAF were modeled using a two-parameter power law function. From the power law model on index of the surface area concentration was obtained. Using a least-square analysis, the power law model was shown to provide a good fit (significant r-squared) for both influent and effluent particle gradations. The overall study results demonstrate the potential of DAF as a competitive and effective size-based separation technology

Numerical Simulation of Fluidic Actuators for Flow Control Applications

Active flow control technology is finding increasing use in aerospace applications to control flow separation and improve aerodynamic performance. In this paper we examine the characteristics of a class of fluidic actuators that are being considered for active flow control applications for a variety of practical problems. Based on recent experimental work, such actuators have been found to be more efficient for controlling flow separation in terms of mass flow requirements compared to constant blowing and suction or even synthetic jet actuators. The fluidic actuators produce spanwise oscillating jets, and therefore are also known as sweeping jets. The frequency and spanwise sweeping extent depend on the geometric parameters and mass flow rate entering the actuators through the inlet section. The flow physics associated with these actuators is quite complex and not fully understood at this time. The unsteady flow generated by such actuators is simulated using the lattice Boltzmann based solver PowerFLOW R . Computed mean and standard deviation of velocity profiles generated by a family of fluidic actuators in quiescent air are compared with experimental data. Simulated results replicate the experimentally observed trends with parametric variation of geometry and inflow conditions

Pilot and Controller Evaluations of Separation Function Allocation in Air Traffic Management

Two human-in-the-loop simulation experiments were conducted in coordinated fashion to investigate the allocation of separation assurance functions between ground and air and between humans and automation. The experiments modeled a mixed-operations concept in which aircraft receiving ground-based separation services shared the airspace with aircraft providing their own separation service (i.e., self-separation). Ground-based separation was provided by air traffic controllers without automation tools, with tools, or by ground-based automation with controllers in a managing role. Airborne self-separation was provided by airline pilots using self-separation automation enabled by airborne surveillance technology. The two experiments, one pilot-focused and the other controller-focused, addressed selected key issues of mixed operations, assuming the starting point of current-day operations and modeling an emergence of NextGen technologies and procedures. In the controller-focused experiment, the impact of mixed operations on controller performance was assessed at four stages of NextGen implementation. In the pilot-focused experiment, the limits to which pilots with automation tools could take full responsibility for separation from ground-controlled aircraft were tested. Results indicate that the presence of self-separating aircraft had little impact on the controllers' ability to provide separation services for ground-controlled aircraft. Overall performance was best in the most automated environment in which all aircraft were data communications equipped, ground-based separation was highly automated, and self-separating aircraft had access to trajectory intent information for all aircraft. In this environment, safe, efficient, and highly acceptable operations could be achieved for twice today's peak airspace throughput. In less automated environments, reduced trajectory intent exchange and manual air traffic control limited the safely achievable airspace throughput and negatively impacted the maneuver efficiency of self-separating aircraft through high-density airspace. In a test of scripted conflicts with ground-managed aircraft, flight crews of self-separating aircraft prevented separation loss in all conflicts with detection time greater than one minute. In debrief, pilots indicated a preference for at least five minute's alerting notice and trajectory intent information on all aircraft. When intent information on ground-managed aircraft was available, self-separating aircraft benefited from fewer conflict alerts and fewer required deviations from trajectory-based operations

Full‐size experimental assessment of the aerodynamic sealing of low velocity air curtains

Funding Information: The need of separating different environment zones (limiting heat and mass transfer) is normally addressed using walls and doors. However, in recent decades, the technology of air curtains has emerged as being capable of providing sufficient separation without impairing the movement of people. Air curtains have been used with several objectives, such as Heating, Ventilation and Air Conditioning (HVAC) [1–3], smoke control in pas‐ sageways [4,5] and airborne pollutant and biological control [6–8]. Regarding the need to avoid the contaminant spreading, several developments and applications have been re‐ ported, namely, in operating rooms [7,9–14], for tobacco smoke control [15,16], for protec‐ tion of art works in museums and of cultural heritage [17,18], in open refrigerated display cabinets [19–21], in offices [22], in personalized air curtains [23] and in public transporta‐ tion [24]. These studies show that air curtains have the potential to reduce the pollutants transferred from one compartment to another. The Nanoguard2ar project (European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska‐Curie grant agreement N 690968) had, as its main objectives, the goal of developing, designing, testing, validating and demonstrating an innovative nanomaterial‐based ‘microbial free’ engineering solution to ensure indoor air quality in buildings,. The development of this engineering solution required not only an advanced nanomaterial‐based oxidation process to kill bacteria in the air in a compart‐ ment, but also an air curtain to provide a separation between the spaces that were to be kept free of cross contamination. The development of the nanomaterial‐based technologyVertical air curtains are often used to separate two different zones to reduce contaminant transfer or even to provide aerodynamic sealing from one zone to the other. In this isothermal full-size experimental research work, the contaminant transfer between zones is reduced using an air extraction from the “contaminated” compartment and an air curtain. This work correlates the min-imum exhaust air flow rate required to reach the aerodynamic sealing at the opening connecting two different zones with the jet nozzle velocity for small nozzle thicknesses (5 mm, 10 mm and 16 mm), particularly for Reynolds numbers below 3800. Following the experimental study, a general physical law that relates the jet parameters (angle, nozzle thickness and jet velocity at the nozzle) with the average velocity through the opening (for the condition of acceptable contaminant tight-ness) was obtained. The results showed that the average velocity of the flow across a door protected by an air curtain required to keep the aerodynamic sealing varies linearly with Re. The slope, how-ever, is different below and above Re = 3820.publishersversionpublishe

Aircraft-to-aircraft separation based on reinforcement learning

Air traffic has been increasing and with it the workload of air traffic controllers. Despite the pandemic, the latest figures show a rapid recovery and forecast exponential growth. This indicates the need to modernise air traffic control and the technology used, which is already being developed and implemented by organisations like SESAR, like applying AI to air traffic control (DART). A support tool with automatic conflict avoidance would be a great step to address the problem of possible overcapacity of air traffic controllers. This document describes two possible implementations of a conflict avoidance tool. The approach is to use Deep Reinforcement Learning to select actions that avoid conflict and help the air traffic controllers to take faster and better decisions. The basis for both approaches is a simple 2D airspace simulator and the same policy applied to all the aircraft. The first proposal is a stand-alone DQN algorithm (DRL) that has a 7.06% improvement in the number of simultaneous conflicts compared to the original environment without applying a policy. The second approach is a DQN algorithm that incorporates transfer learning of the rules of the air, and it is called by the acronym DRLT. It resulted in a degradation compared to the original environment, with a 6% increase in unremembered conflicts. Nevertheless, Deep Reinforcement Learning has shown a decrease in decision time and the idea of reusing the same strategy for all aircraft has solved the problem of unpredictability issue that some reinforcement learning solutions had. The proposal could be a good start for a self-separation tool for unmanned aircraft but still needs future improvements in results. It is not suitable for air traffic controllers or piloted vehicles due to the increased workload it would suppose

Design and Integration Analysis of Cryogenic Air Separation Unit

Industrial Gas market is expected to grow to $106 billion from$76 billion by 2022 parallel to the global energy and chemical production sector growth. Air separation is one of the major technologies utilized within this industry to supply Nitrogen, Oxygen and Inert gasses for various industrial applications. Cryogenic separation has emerged as a technology of choice for high capacity and high purity units, but it is also known for its high energy intensive characteristic. Cryogenic air separation units (CASU) utilize electricity to produce refrigeration for liquefaction and separation of air components, operating near temperatures as low as 78 K and consuming around 200kWh/ton oxygen product. Even 1% increase in efficiency can result in millions of dollars of energy savings annually. CASU technology inherits tight heat integration with approach temperatures of up to ~1oC in the heat exchangers due to refrigeration at very low temperatures. This work is intended to systematically study and analyze the dependence of energy usage of this technology on process design, utilize the insights of this analysis to develop a framework for design improvement and operation of the plant, and develop heat integration map of the unit operations. Benchmarking of this heat integration is performed using pinch analysis. As part of the work, sensitivity analysis of the complex thermally coupled sequential distillation system is also presented. Well established benchmarking and targeting techniques pioneered by Dr. El- Halwagi are used to investigate the ‘big picture’ without getting into heat exchanger network details. The novel insight presented by this research is the dependence of enthalpy flow into the separation section on the product recoveries. A unique way to assess heat flow by dissecting the process into smaller control volume helps in overall enthalpy balance which helps in estimating important process parameters. This helps in reducing the handles available for process modification. Finally, a case study is presented where the implementation of control volume approach and resultant process improvement is demonstrated

Opening Autonomous Airspace–a Prologue

The proliferation of Unmanned Aerial Vehicles (UAV), and in particular small Unmanned Aerial Systems (sUAS), has significant operational implications for the Air Traffic Control (ATC) system of the future. Integrating unmanned aircraft safely presents long-standing challenges, especially during the lengthy transition period when unmanned vehicles will be mixed with piloted vehicles. Integration of dissimilar systems is not an easy, straight-forward task and in this case is complicated by the difficulty to truly know what is present in the airspace. Additionally, there are significant technology, security and liability issues that will need resolution to ensure property and life are protected and in loss, indemnified. The future of air traffic will be a fully networked environment, where the absence of participation on the network could connote a potential intruder and threat. This article explores a potential airspace structure, and conceptual air traffic management philosophy of self-separation that is inclusive of all participants. Additionally, the article acknowledges the significant cyber security, technological, societal trust, employment, policy, and liability implications of transition to a fully autonomous air transportation system. Each subject is described at a macro, operations analysis level verses a more detailed systems engineering level. The objective and potential value of such a treatment is to encourage industry dialog about possibilities and more importantly a focus toward workable future air traffic solutions