Advanced Weather Displays for TRACON Controllers
Updated:02:58 PM March 20, 2009
Hazardous weather conditions affect the National Airspace System (NAS) in many ways including flight safety and system effectiveness. They create safety hazards for pilots, constrain the usable airspace for air traffic control (ATC), and reduce the overall capacity of the NAS. Providing controllers with the capability to display advanced weather information could be one way to improve the ability of the NAS to deal with adverse weather.
The architecture and evolution plans for the Standard Terminal Automation Replacement System (STARS) specifies the use of Integrated Terminal Weather System (ITWS) products for terminal ATC. However, the decision to use ITWS in terminal ATC was not based on an actual evaluation of weather tools on controller displays. No previous research has shown what types of weather information is most useful for controllers, and we have few guidelines for optimal display of weather visualizations (Ahlstrom & Della Rocco, 2003). As a consequence, there is little data available for decision makers trying to assess the risks and the cost/benefits of implementing weather information on controller displays.
To investigate the benefits and human factors issues associated with displaying weather information on controller displays, researchers from the NAS Human Factors group conducted a severe weather avoidance simulation at the Research and Development Human Factors Laboratory (RDHFL). In an initial project phase, we conducted a Cognitive Work Analysis (CWA) of the terminal domain to assess terminal controllers’ weather information needs (Ahlstrom, 2004). Included in the analysis team were six commercial airline pilots and five terminal controllers.
Next, we used the CWA analysis result to drive the development of weather display tools and a high-fidelity simulation capability. An important outcome of this effort was the development of an auxiliary Weather Information Display System for experimental use (WIDS: Ahlstrom, Keen, & Mieskolainen, 2004). Figure 1 illustrates the use of the WIDS in combination with the STARS workstation.
 Figure 1. An illustration of weather display presentations on the WIDS (top display) and the STARS workstation (bottom display). Click on image to see full-size image (89 Kb) |
In a third project phase, we conducted a human-in-the-loop weather simulation where we manipulated the display of advanced weather information (i.e., storm motion forecasts) and compared this to a control condition where controllers had no advanced weather information (current field operations). The advanced weather information (i.e., storm motion, gust front, wind shear, microburst, and echo tops) consisted of pre-recorded ITWS data and specifically developed prototypes of dynamic storm motion forecasts. A display illustration of this weather information is shown in Figure 2.
Eleven non-supervisory, full-performance level TRACON controllers volunteered as participants for the simulation. To allow an examination of the effects of advanced weather information, we included a procedure that assigned responsibility for keeping aircraft away from weather Levels 4, 5, and 6, to the controller. This procedure is not used in current TRACON field operations.
Figure 2. An illustration of a display with traffic and weather data superimposed. The illustration shows six levels of precipitation (Levels 1-3 blue shaded areas, and Levels 4-6 brown shaded areas), current storm cell position (solid blue line), extrapolated storm cell positions for 10 and 20 minutes into the future (blue dotted lines), microburst (shaded red circle), and windshear (red circle). The dynamic storm forecasts provided motion estimates by a spatial displacement of the shaded areas for Level 4-6 cells. Click on image to see full-size image (115 Kb). |
The result showed that when controllers had access to dynamic storm forecast tools at their workstation, they increased the average sector throughput by 6-10% compared to conditions where no weather information was available (Ahlstrom & Friedman-Berg, 2006a). Furthermore, because weather tools were available, controllers handled more aircraft without a corresponding increase in their ratings of cognitive workload (Ahlstrom & Friedman-Berg, 2005a). Extending our workload analysis using eye movement data, we found evidence of less efficient controller scan-path behavior and higher visuospatial workload during the use of static weather tools compared to the use of dynamic weather tools (Ahlstrom & Friedman-Berg, 2006b). We also conducted in-depth analyses of how controllers used the various weather tools in the simulation to provide guidelines for future development of tactical weather tools (Friedman-Berg & Ahlstrom, 2005b). Additionally, we analyzed controller preferences for luminance contrast in displays with traffic and weather data, and assessed possible ways to optimize the use of color in operational weather displays (Ahlstrom & Arend, 2005).
In summary, by providing controllers with enhanced weather information at the workstation, we enhanced controllers’ ability to detect approaching weather, monitor its movement, and understand its effect on future operations. This result is important in that it improves the chances for FAA to procure weather products with real operational value. Furthermore, it shows that by reducing the uncertainty about weather conditions, controllers can make better decisions that will positively affect safety and efficiency of terminal ATC operations.
Federal Aviation Administration
William J. Hughes Technical Center, Building 28
Atlantic City International Airport, NJ 08405
Phone:(609) 485-8642
Fax: (609) 485-6218
ulf.ahlstrom@faa.gov
References & Products
Ahlstrom, U. & Arend, L. (2005). Color usability on air traffic control displays. In Proceedings of the Human Factors and Ergonomics Society 49th Annual Meeting (pp. 93-97). Santa Monica, CA: Human Factors and Ergonomics Society.
Ahlstrom, U., Keen, J., & Mieskolainen, A. J. (2004). Weather Information Display System (WIDS). Journal of Air Traffic Control, 46(3), 7-14.
