Jeffrey Homola

Toward Automated Air Traffic Control—Investigating a Fundamental Paradigm Shift in Human/Systems Interaction

Predicted air traffic increases over the next 25 years may create a significant capacity problem that the United States National Airspace System will be unable to accommodate. The concept of introducing automated separation assurance was proposed to help solve this problem. However, the introduction of such a concept involves a fundamental paradigm shift in which automation is allowed to perform safety-critical tasks that today are strictly the air traffic controllers domain. Moving toward automated air traffic control, therefore, requires a careful and thorough investigation. As part of an ongoing series, three human-in-the-loop simulation studies were conducted at the NASA Ames Research Center with the overarching goal of determining whether the automated separation assurance concept can be integrated into air traffic control operations in an acceptable and safe manner. These studies investigated a range of issues including the proper levels of automation for given capacity targets, off-nominal operations from both air and ground perspectives, and sustained near-full mission operations with many tasks allocated to the automation in the presence of convective weather and scheduling constraints. Overall, it was found that the concept has the potential to solve the envisioned airspace capacity problem. The automation was largely effective and robust, and the function allocation of tasks between controllers and automation was generally acceptable. However, feedback and results also showed that further technological development is necessary to improve trajectory prediction and conflict detection accuracy. The need for further procedural development to govern controller/automation and air/ground interactions was also highlighted. These and other considerations are addressed as the automated separation assurance concept is further tested and pursued through subsequent studies. This article not subject to US copyright law.

A Human-in-the Loop Exploration of the Dynamic Airspace Configuration Concept

An exploratory human-in-the-loop study was conducted to better understand the impact of Dynamic Airspace Configuration (DAC) on air traffic controllers. To do so, a range of three progressively more aggressive algorithmic approaches to sectorizations were chosen. Sectorizations from these algorithms were used to test and quantify the range of impact on the controller and traffic. Results show that traffic count was more equitably distributed between the four test sectors and duration of counts over MAP were progressively lower as the magnitude of boundary change increased. However, taskload and workload were also shown to increase with the increase in aggressiveness and acceptability of the boundary changes decreased. Overall, simulated operations of the DAC concept did not appear to compromise safety. Feedback from the participants highlighted the importance of limiting some aspects of boundary changes such as amount of volume gained or lost and the extent of change relative to the initial airspace design.

Effect of Dynamic Sector Boundary Changes on Air Traffic Controllers

The effect of dynamic sector boundary changes on air traffic controller workload was investigated with data from a human-in-the-loop simulation. Multiple boundary changes were made during simulated operations, and controller rating of workload was recorded. Analysis of these data showed an increase of 16.9% in controller workload due to boundary changes. This increased workload was correlated with the number of aircraft handoffs and change in sector volume. There was also a 12.7% increase in average workload due to the changed sector design after boundary changes. This increase was correlated to traffic flow crossing points getting closer to sector boundaries and an increase in the number of flights with short dwell time in a sector. This study has identified some of the factors that affect controller workload when sector boundaries are changed, but more research is needed to better understand their relationships.

Sector Design and Boundary Change Considerations for Flexible Airspace Management

In Next Generation Air Transportation System (NextGen) operations, we expect that the demand-capacity balance can be achieved by selectively managing the airspace capacity in conjunction with managing the traffic demand. In Flexible Airspace Management (FAM), the airspace complexity can be assessed a few hours ahead in order to identify sectors that could exceed their defined traffic threshold as well as sectors that are under-utilized. Using various airspace optimization algorithms, airspace can be reconfigured to manage the existing traffic demand without moving aircraft away from their original user-preferred routes. A human-in-the-loop simulation study was conducted in 2009 to assess the impact of airspace reconfiguration on the controllers. The results from the objective data found that the acceptability of the boundary change and the associated workload were mainly affected by airspace volume change and aircraft that changed ownership. However, observations and subjective feedback have suggested that other cognitively-driven factors, such as spatial relationships between upstream/downstream sectors, may also play a role, especially in traffic situations where the airspace has only a few aircraft that change ownership but still has a high degree of airspace complexity associated with the reconfiguration. In this paper, we identify these factors and discuss the human factors issues that should be considered in designing the airspace and airspace transitions.

Multifactor interactions and the air traffic controller: the interaction of situation awareness and workload in association with automation

Abstract Air traffic controllers must maintain a consistently high level of human performance in order to maintain flight safety and efficiency. In current control environments, performance-influencing factors such as workload, fatigue and situation awareness can co-occur and interact to affect performance. However, multifactor influences and the association with performance are under-researched. This study utilised a high-fidelity, human-in-the-loop, en route air traffic control simulation to investigate the relationship between workload, situation awareness and controller performance. The current study aimed to replicate Edwards et al.’s (in: Proceedings of the 4th AHFE international conference, 21–25th July, San Francisco, USA, 2012) previous finding that factors known to be associated with controller performance do co-vary and can interact, which is associated with a compound influence on performance. In addition, the current study aimed to extend Edwards et al.’s (2012) study by engaging retired controllers as participants and comparing multifactor relationships across four levels of automation. Results suggest that workload and situation awareness may interact to produce a compound (as opposed to cumulative) impact on controller performance. In addition, the effect of the interaction on performance may be dependent on the context and level of automation. Findings have implications for human–automation teaming in air traffic control, and the potential prediction of performance-influencing situations, supporting controller performance in the operational environment.

Human/automation response strategies in tactical conflict situations

A human-in-the-loop simulation was conducted that examined off-nominal and tactical conflict situations in an advanced Next Generation Air Transportation System (NextGen) environment. Traffic levels were set at two times (2X) and three times (3X) current day levels and the handling of tactical conflict situations was done either with or without support from Tactical Separation Assisted Flight Environment (TSAFE) automation. Strategic conflicts and all routine tasks performed in todays system were handled by ground-based automation. This paper focuses on the response strategies observed in two scripted tactical conflict situations and how they differed according to whether or not automated resolution support was provided by TSAFE. An examination of the two situations revealed that when TSAFE automation was active, participants tended to provide additional, complementary maneuvers to supplement the tactical vector issued by TSAFE. This also included a greater tendency to use both aircraft in a conflict pair. When TSAFE support was not available, participants tended to use single vector or altitude maneuvers and were more likely to attempt resolutions using a single aircraft as well. Some issues that arose through the operations simulated in this study related to the need for the Air Navigation Service Provider (ANSP) to be able to have final authority over the issuance of TSAFE maneuvers as well as the importance of having awareness of the immediate traffic situation in making effective and safe time-critical decisions.

Investigating the complexity of transitioning separation assurance tools into nextgen air traffic control

In a study, that introduced ground-based separation assurance automation through a series of envisioned transitional phases of concept maturity, it was found that subjective responses to scales of workload, situation awareness, and acceptability in a post run questionnaire revealed as-predicted results for three of the four study conditions but not for the third, Moderate condition. The trend continued for losses of separation (LOS) where the number of LOS events were far greater than expected in the Moderate condition. To offer an account of why the Moderate condition was perceived to be more difficult to manage than predicted, researchers examined the increase in amount and complexity of traffic, increase in communication load, and increased complexities as a result of the simulations mix of aircraft equipage. Further analysis compared the tools presented through the phases, finding that controllers took advantage of the informational properties of the tools presented but shied away from using their decision support capabilities. Taking into account similar findings from other studies, it is suggested that the Moderate condition represented the first step into a “shared control” environment, which requires the controller to use the automation as a decision making partner rather than just a provider of information. Viewed in this light, the combination of tools offered in the Moderate condition was reviewed and some tradeoffs that may offset the identified complexities were suggested.

Human-in-the-Loop Investigation of Airspace Design

A part-task, human-in-the-loop study on Flexible Airspace Management (FAM) was conducted to explore the role of algorithm-generated airspace designs, human-centered design practices, and the potential benefits of FAM within these contexts. Participants were independently exposed to 4and 7-sector traffic scenarios that involved sector load imbalances due to reroutes around convective weather. Peak sector loads were well above the imposed threshold of 22 aircraft and required active management in each of the following conditions: No Boundary Change (No BC) in which traffic load imbalances were addressed through reroutes alone, Manual BC in which participants modified the existing airspace boundaries to reduce and redistribute load imbalances followed by reroutes for the remaining excess, and Algorithm + Manual BC in which sets of algorithm-generated boundary configurations were available for selection and further modification followed by reroutes to reduce remaining excess traffic load. Overall, results showed that FAM operations in the Manual and Algorithm + Manual BC conditions required fewer reroutes and managed peak sector loads better than the No BC condition. Furthermore, algorithmgenerated airspace designs and the support they provided in the Algorithm + Manual BC condition resulted in consistent benefits in terms of fewer reroutes and better peak management than in the Manual BC condition. Feedback from participants also highlighted the beneficial role of airspace optimization algorithms in FAM by providing a means of developing more acceptable and effective airspace designs and overall solutions to the problems presented.

Unmanned Aircraft Systems (UAS) Traffic Management (UTM) National Campaign II

The Unmanned Aircraft System (UAS) Traffic Management (UTM) effort at NASA aims to enable access to low-altitude airspace for small UAS. This goal is being pursued partly through partnerships that NASA has developed with the UAS stakeholder community, the FAA, other government agencies, and the designated FAA UAS Test Sites. By partnering with the FAA UAS Test Sites, NASA’s UTM project has performed a geographically diverse, simultaneous set of UAS operations at locations in six states. The demonstrations used an architecture that was developed by NASA in partnership with the FAA to safely coordinate such operations. These demonstrations—the second or “Technical Capability Level (TCL 2)” National Campaign of UTM testing—was performed from May 15 through June 9, 2017. Multiple UAS operations occurred during the testing at sites located in Alaska, Nevada, Texas, North Dakota, Virginia, and New York with multiple organizations serving as UAS Service Suppliers and/or UAS Operators per the specifications provided by NASA. By engaging various members of the UAS community in development and operational roles, this campaign provided initial validation of different aspects of the UTM concept including: UAS Service Supplier technologies and procedures; geofencing technologies/conformance monitoring; groundbased surveillance/sense and avoid; airborne sense and avoid; communication, navigation, surveillance; and human factors related to UTM data creation and display. Additionally, measures of performance were defined and calculated from the flight data to establish quantitative bases for comparing flight test activities and to provide potential metrics that might be routinely monitored in future operational UTM systems.

Technical capability level 2 unmanned aircraft system traffic management (UTM) flight demonstration: Description and analysis

NASAs UAS Traffic Management (UTM) project concluded its second flight demonstration activity in late October 2016. This activity demonstrated the capabilities and functionality incorporated into its Technical Capability Level 2 (TCL 2) concept, which envisions future operations that are low density, capable of being performed over sparsely populated areas, and allow for a concurrent mix of longer duration, beyond visual-line-of-sight flights and shorter flights within visual-line-of-sight (VLOS). To incorporate these features into a flight demonstration, a scenario-based approach was taken to address different aspects of the TCL 2 environment and to meet defined objectives. This paper will describe elements of how the flight activity was conducted and present analyses regarding UTM operations, system messages, and alerting as they pertained to meeting the demonstration objectives and shedding light on research questions and lessons learned.