Safe Flight 21 Human Factors
Updated:02:58 PM March 20, 2009
The Safe Flight 21 program is developing and evaluating the use of Automatic Dependent Surveillance – Broadcast (ADS-B) capabilities for providing highly accurate aircraft location, identification, and status (e.g., altitude, ground speed, heading) to air traffic controllers on their radar displays and to other pilots via a Cockpit Display of Traffic Information (CDTI). Since 1999, the Human Factors Team-Atlantic City has been collaborating with other organizations in the design and operational evaluation of the controller and pilot displays and procedures utilizing ADS-B.
In 1999, we participated in Operational Evaluation 1 (OpEval 1) at the Airborne Express airport in Wilmington, Ohio. Eight Cargo Airlines Association aircraft equipped with CDTIs flew instrument approaches to the parallel runways while using their CDTIs to acquire and monitor other traffic on approximately 2/3 of the approachs. The CDTIs were covered on the remaining approaches to serve as a baseline measure. Four more aircraft flew extended en route patterns while using their CDTIs for station keeping and in-trail climbs and descents. The controllers at Dayton TRACON had no additional displays, but we observed their operations and collected data about their workload and perceptions of pilot use of the CDTI. Both pilots and controllers thought the CDTI could be beneficial in terms of increased safety and efficiency, but they identified several potential problems, such as display clutter and excessive pilot head-down time.
In 2000, we participated in OpEval 2 at Louisville’s Standiford Airport, the hub for United Parcel Service (UPS). Seventeen aircraft equipped with CDTIs participated in multiple activities to evaluate their use for departure spacing, approach spacing, final approach runway occupancy awareness, and airport surface situation awareness. In addition, we evaluated the use of ADS-B in full and mixed equipage scenarios, the use of new procedures for including traffic-to-follow call signs in clearances, and a controller display of ADS-B information. The Human Factors Team-Atlantic City activities were focused on the terminal controllers, but we were also involved in planning and analysis from the pilot and tower controller viewpoints. Both pilots and controllers thought the use of the CDTI was beneficial for some applications and conditions, but it increased pilot workload on final approach. They agreed that the communication procedures needed improvement and that the mixed equipage environment increased the controller’s workload and limited the utility of the CDTI for the pilots. Finally, the controllers indicated the ADS-B display was an improvement over their current radar display, but some elements of the available information and functionality were not acceptable.
Since OpEval 2, we have consulted with other elements of the SF21 program working on the use of ADS-B data and CDTIs in Alaska (known as the Capstone project), on developing guidelines for moving map displays, and on evaluating additional applications for ADS-B data, in particular the CDTI Enhanced Flight Rules (CEFR) application. In CEFR, pilots can remain on a visual clearance by following a lead aircraft on their CDTI once visual contact is made out the window. This application is most useful when maintaining visual contact is difficult because of haze, sun glare, and at night, when leading aircraft lights become lost in other airport or nearby city lights. We have led efforts to develop a computer-human interface (CHI) for integrating ADS-B data into the controller radar display in a mixed equipage environment. We have used our rapid prototyping capabilities to work with the Surveillance Integration Team (SIT) to explore display options and the associated functionality needed for controllers to use the data effectively. Some of the issues included target shape, size, and color; frequency of display updating; synchronization of updates with radar targets; and the use of ADS-B inhibition and display suppression functions. We have completed the specifications for the Common Automated Radar Terminal System so that the system can be built and used for operational evaluation at Louisville airport with equipped UPS aircraft.
Products
- Surveillance Integration Team. (2003). Thinspecs for ADS-B on Common ARTS.
