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11 papers found

Paper 10 -- Statistical Performance Evaluation Between Linear And Nonlinear Designs For Aircraft Relative Guidance

Over the last few years, several concepts concerning the delegation to the flight crew of some tasks currently performed by the air traffic controllers have emerged. Among these new ideas, relative guidance has appeared to be capable to contribute to the enhancement of air traffic capacity though it raises difficult technical challenges. Indeed, this kind of maneuver appears difficult to perform manually, and may induce an excessive increase in flight crew workload, thus requiring new on-board automated functions. Some linear and nonlinear techniques have already been applied to design a feedback loop which performs automatically merging maneuvers and maintains station keeping behind a designated aircraft. The main contributions of the paper consist in a new nonlinear design of the feedback control loop and in the comparison between a linear design and the proposed nonlinear design, namely a proportional/derivative design and the proposed backstepping design. The comparison is based on Monte Carlo simulations, and promotes the nonlinear design. Indeed, a touch of complexity in the design process allows for better performances: backstepping fosters quick achievement of merging and station keeping maneuvers.
Theme: Innovative ATM Concepts
Posted by: Thierry MIQUEL / Other authors: Jean Marc LOSCOS

Paper 17 -- Air And Ground Simulation Of Terminal-Area Fms Arrivals With Airborne Spacing And Merging

A combined air and ground simulation of terminal-area arrival operations was conducted at NASA Ames Research Center to evaluate Distributed Air Ground Traffic Management (DAG-TM) project Concept Element 11 (CE 11): Terminal Arrival: Self-Spacing for Merging and In-trail Separation. The simulation was the final DAG-TM study conducted at NASA Ames with funding from the NASA Airspace Systems Program Advanced Air Transportation Technologies (AATT) project. The study evaluated the feasibility and potential benefits of using pilot and controller decision support tools (DSTs) to support time-based airborne spacing and merging in terminal radar approach control (TRACON) airspace. Sixteen simulation trials were conducted in each treatment combination of a 2x2 repeated measures design. In trials with ground tools, air traffic controller participants managed traffic using sequencing and spacing DSTs. In trials with air tools seventy-five percent of aircraft assigned to the primary landing runway were equipped for airborne spacing and merging, including flight simulators equipped with an enhanced cockpit display of traffic information (CDTI) flown by commercial pilots. In all trials controllers were responsible for separation and issued clearances by voice. All aircraft were equipped with Flight Management Systems (FMSs) and ADS-B and entered TRACON airspace on charted FMS routes. Routes to the primary landing runway merged. Each scenario began with a traffic flow that was well coordinated for merging and spacing and ended with an uncoordinated flow. This paper presents the simulation and results of from an air traffic management (ATM) perspective. The results indicate that airborne spacing improves spacing accuracy and is feasible for FMS operations and mixed spacing equipage. Airborne spacing capabilities and the degree of flow coordination affect clearance selection. Controllers and pilots can manage spacing clearances that contain two callsigns without difficulty. For best effect, both DSTs and spacing guidance should exhibit consistently predictable performance.
Theme: Undefined
Posted by: Todd Callantine / Other authors: Paul Lee

Paper 78 -- Human Factors Implications Of Continuous Descent Approach Procedures For Noise Abatement In Air Traffic Control

Continuous Descent Approach (CDA) procedures can be effective at reducing aircraft noise around airports. The human factors implications for the air traffic controller of transitioning from conventional to CDA procedures are addressed in this paper. Different types of CDA procedures are introduced and models are developed of the controller tasks undertaken during current approach operations. The models are used to perform cognitive difference analyses to highlight the implications of using CDA procedures, particularly with respect to differences in intent, controllability and structure-based abstractions in the lateral, vertical and speed domains. An experiment is described to probe the cognitive implications of one of the key differences between the procedures: removal of periods of constant speed. All of the findings are summarized to provide CDA design guidance in order to ease transition and controller acceptance of their use.
Theme: Environmental Impacts and Mitigation
Posted by: Hayley Davison Reynolds / Other authors: Tom Reynolds

Paper 100 -- User Request Evaluation Tool (Uret) Adoption And Adaptation; Three Center Case Study

The objective of this paper is to present findings of exploratory interviews regarding the air traffic controllers adoption and adaptation of User Request Evaluation Tool(URET). The importance of this investigation lies in better understanding of changes brought about by the use of Decision Support Tools by sector controller teams and what can be done to avoid some of the unintended consequences.The main purpose of URET is to support sector team strategic planning allowing controllers to concentrate on more user-beneficial control actions. Actual improvements depend on the way controllers use the automation tools in their work. Three things have been noticed about usage of URET: first, different sector teams use it in different ways; second, in many instances URET usage differs from what was intended; and third, the usage varies across centers. We interviewed subject matter experts to explore how controllers have adopted and/or adapted URET in three different Air Route Traffic Control Centers (ARTCC), across mentioned variations.The goal of this research is to draw lessons from the experience with URET that can inform technology deployments in the future.
Theme: Human Factors
Posted by: Tatjana Bolic / Other authors: Mark Hansen

Paper 105 -- Conflict Perception By Atcs Admits Doubt But Not Inconsistency

Though there is considerable agreement among the past studies about the great variability in conflict judgments by Air Traffic Control Specialists (ATCS), this work puts a first step forward in direction of a common core shared by controllers for perceiving conflicts. First, traffic scenarios were built from real traffic recordings, showing two converging aircraft. Three variables characterized these scenarios, respectively quantifying horizontal and vertical separations and the time when the judgment had to be formulated. The conditions created by factorial manipulation of three variables led to the design of short scenarios (about 1 min) upon which 161 controllers gave their opinion about the possible occurrence of separation loss (less than 3 NM and 1000 feet). The data, currently being analyzed, already show an important variability among experts, confirming the results of the past studies. But the way that the median values of responses are spread over the combinatory range of the scenarios appears very coherent and could prefigure a model of conflict perception by ATCS community. Further, values guaranteeing a certain level of security have been found and compared both on the horizontal plane and altitude. It shows (and quantifies) the higher efficiency, or reliability of those obtained on the plane. Considering anticipation in the judgment (variable D°A), it shows how uncertainty varies while anticipation decreases. Moreover, particular variations of uncertainty appear within responses resulting from scenarios with near minima separation values. These variations tend to evidence the line of thought of ATCSs dealing with the limits of the margin they have to set for a conflict/non-conflict classification.
Theme: Human Factors
Posted by: Philippe Averty

Paper 108 -- Quantifying Convective Delay Reduction Benefits For Weather/Atm Systems

In this paper, we discuss ongoing efforts to quantify convective weather delay reduction benefits for weather/ATM systems and recommend approaches for future assessments.This is particularly important at this time because:1. convective weather delays have become a dominant factor in the overall National Air System (NAS) delays (figure 1), and 2. Benefits quantification and NAS performance assessment have become very important in an era of significant federal government and airline budget austerity for civil aviation investmentsConvective weather events are in general not repeatable (unlike many low ceiling and visibility events) and, give rise to highly nonlinear queue driven delays in congested airspace.Hence, seemingly straightforward comparisons of delays cannot be easily carried out.In this paper, we first discuss at some length the mechanisms by which convective weather delay occurs in the NAS and highlight challenges in delay reduction assessment.We consider this to be very important since one needs to understand how the system operates if one is to design an effective, accurate performance assessment system.We then describe practical results from ongoing analysis of delay reduction for both terminal and enroute systems using user interviews, direct observations of ATM decision making in convective weather, and analysis of delay statistics.The paper concludes for recommendations for future convective weather delay reduction quantification studies.
Theme: Decision Support
Posted by: James Evans / Other authors: Michael Robinson

Paper 114 -- Modeling Delays And Cancellation Probabilities To Support Strategic Simulations

Modeling delays and cancellation probabilities is important for strategic-level decision support tools in aviation planning.In this paper, we introduce models for average delays and cancellation probabilities that distinguish between carriers but do not rely on proprietary information.The models were developed for a strategic simulation to determine the effects of congestion management schemes at LaGuardia Airport, including government regulations, administrative controls, and congestion prices.We also demonstrate the use of the models to help determine the appropriate number of hourly slots to offer in a hypothetical slot auction.
Theme: Metrics and Performance Management (System Arch)
Posted by: David Lovell / Other authors: Avijit Mukherjee

Paper 116 -- Response Mechanisms For Dynamic Air Traffic Flow Management

Dealing with uncertainty and changing conditions represents a major challenge in air traffic flow management (ATFM).We use the newly developed slot credit substitution (SCS) mechanism as a prototypical example to understand how fast-response, dynamic mechanisms can improve ATFM performance.We develop a quantitative model that estimates the difference in impact of a batch-oriented periodic process and a fast-response asynchronous process and describe some key properties of fast-response mechanisms derived from the SCS case.
Theme: Traffic Flow Optimization
Posted by: Michael Ball / Other authors: Robert Hoffman

Paper 119 -- The Factors Affecting Airspace Capacity In Europe: A Framework Methodology Based On Cross Sectional Time-Series Analysis Using Simulated Controller Wo

Air traffic in Europe is increasing at a rapid rate and traffic patterns no longer display pronounced daily peaks but instead exhibit peak spreading. Airspace capacity planning can no longer be for the peak period but must consider the whole day. En-route airspace capacity in the high density European air traffic network is determined by controller workload. Controller workload is primarily affected by the features of the air traffic and ATC sector and capacity is usually estimated using the simulation model, the Re-organized ATC Mathematical Simulator (RAMS) model of air traffic controller workload. This paper considers the air traffic and ATC sector factors that affect controller workload throughout the whole day and provides a framework using cross-sectional time-series analysis of the RAMS simulation output. Two simulation studies are presented in contrasting regions of European airspace to show the robustness of the method. Controller interviews are used to enhance the analysis. The results indicate that a sub-set of traffic and sector variables and their parameter estimates can be used to predict controller workload in any sector of the two regions simulated in any given hour.
Theme: Undefined
Posted by: Arnab Majumdar / Other authors: Washington Ochieng

Paper 120 -- Safety Analysis For Advanced Separation Concepts

Aviation panels have called for increasing the capacity of the air transportation system by as much as a factor of three over the next 20 years. The inherent spatial capacity of en route airspace appears able to accommodate the resulting traffic densities. But controller workload presents a more formidable obstacle to achieving such goals. New approaches to providing separation assurance are being investigated to allow airspace capacity to be fully utilized. One approach is to develop computer automation as the basis for separation-assurance processes. This would permit traffic densities that exceed the level at which human cognition and decision-making can function. One of the challenges that must be faced involves the ability of such highly automated systems to maintain safety in the presence of inevitable subsystem faults, including the complete failure of supporting computer systems. Traffic density and flow complexity will make it impossible for human service providers to safely reinitiate manual control in the event of computer failure, so the automated system must have inherent fail-soft features.This paper presents a preliminary analysis of the ability of highly automated separation assurance system to tolerate general types of faults such as nonconformance and computer outages. Safety-related design features are postulated using the Advanced Airspace Concept (AAC) as a basis. Special attention is given to the impact of a severe failure in which all computer support is terminated within a defined region. The growth and decay of risk during an outage is evaluated using fault tree methods that integrate risk over time. It is shown that when a conflict-free plan covers the region of the outage, this plan can be used to safely transition aircraft to regions where service can still be provided.
Theme: Safety
Posted by: John Andrews

Paper 134 -- Verification And Validation Results From The Operational A-Smgcs Field Trials Of The Project Beta

A-SMGCS is a modular concept defined in the ICAO Manual on A-SMGCS (Doc9830). A-SMGCS systems are aiming to provide adequate capacity and safety in relation to specific weather conditions, traffic density and aerodrome layout. With the complete concept of an A-SMGCS, ATS providers and flight crews are assisted in terms of surveillance, control, planning and guidance tasks. To facilitate the implementation of A-SMGCS and to mature the necessary technology and operating procedures, the European Commission funded the project BETA (operational Benefit Evaluation by Testing A-SMGCS) within the 5th framework programme. Two sample A-SMGCS systems were installed at the two European mid-size airports Hamburg and Prague using equipment from Industry and R&D labs. The operators were trained in simulation and on-site. The prototype A-SMGCS installations have been used to control the regular airport traffic from a separate BETA controller working position in the Tower. Appropriate testing methodologies concerning functional and operational testing were developed and fed forward to the European MAEVA validation standard. Significant progress was made with the maturation of the technical equipment. Operational issues like proper transponder switching have been tackled. The benefit categories of an A-SMGCS were identified and qualified. The paper presents the BETA approach, the main findings and results as well as the main lessons learnt.
Theme: Airport Management
Posted by: Christoph Meier

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