Measuring Behavior 2005: Prinzo

Terminal radar approach control: Measures of voice communication system performance

O.V. Prinzo

FAA Civil Aerospace Medical Institute, Oklahoma City, Oklahoma, USA

Communications in the National Airspace System (NAS) are an essential safety component to successful air travel. As the NAS migrates from its current ground infrastructure and voice communications system to one that encompasses both ground and airborne systems, digital data transmissions may become the principal communication medium. When technological advances lead to innovations in communications system development, these emerging systems may be evaluated against the existing legacy system’s performance parameters such as setup delay, voice streaming, pause duration and message propagation. The data presented here are but a first step in providing objective and quantifiable communications system performance metrics that may prove valuable to communications systems developers and personnel charged with the evaluation, certification, and deployment of the next generation of communications systems. Nearly 8000 transmissions were analyzed, using the NiceLogger™ Digital Voice Reproducer System and Adobe Audition™ 1.5 audio software. These transmissions represented the busiest air-ground communications from the five terminal radar approach control facilities with the highest number of operations in the contiguous United States. Typically, setup delays lasted 81 ms, voice streaming 2568 ms, pause duration 127 ms, and message propagation 73 ms for a total of 2849 ms per transmission. On average, transmissions were separated by 1736 ms of silence. Disruptions to efficient information transfer can result from blocked, stepped-on, and clipped transmissions — but they are rare events and occurred in only 1.16% of the sampled transmissions. A comparison between aircraft with and without disruptions revealed that when a disruption was present, an average of 14.54 messages were transmitted compared with an average of 9.90 messages when no disruption was present. Even so, there appears to be some type of a detection mechanism in place to alert the controller to the presence of blocked transmissions. The source is of this detection system is unclear; however, systems developers may want to exploit and expand this capability to include stepped-on and clipped transmissions.

Paper presented at Measuring Behavior 2005 , 5^th International Conference on Methods and Techniques in Behavioral Research, 30 August - 2 September 2005, Wageningen, The Netherlands.