Publications

The Runway Status Light System (RSLS), developed under the FAA's Airport Surface Traffic Automation (ASTA) program, is intended to help reduce the incidence of runway incursions and airport surface accidents. It will do so by providing a preventive, back-up system of automatically controlled lights on the airport surface that inform pilots when runways are unsafe for entry or takeoff, and by providing controllers with enhanced surface radar displays. This report documents a proof-of-concept evaluation of the RSLS at Boston's Logan Airport. It details the methods used to provide the necessary surface surveillance and safety logic to allow a computer to operate the runway status lights and associated controller displays without human assistance. The system was installed and tested off-line at Boston's Logan Airport using an inexpensive commercial marine radar as a primary surveillance source. The system operated live and in real time but the runway status lights were not physically installed. They were displayed on a scale model of Logan Airport located in a demonstration room that had a good view of the airport. This allowed visual comparison between the actual aircraft and the resulting lights and displays. In addition to providing a convincing demonstration of the system, real-timing viewing of the aircraft movement was an important aid in the development of the surveillance processing and safety logic software. Surveillance performance and runway status light operational performance were evaluated quantitatively. The probability of tracking an aircraft in movement areas with line-of-sight coverage was better than 98%. The false track rate was about four per hour, and the surveillance jitter was about 1 meter rms. From an operational point of view, had there been real lights on the field, it appears that they would have provided the intended safety back-up with little impact on airport capacity or controller and pilot workload, Only once in 15 minutes would the pilot population have observed a light in an incorrect state for more than four seconds. From the point of view of a specific cockpit crew, only once in 36 operations would a runway status light have been seen in an incorrect state for more than four seconds, and, furthermore, only once in 50 operations would light illuminations have interfered with normal, safe traffic flow. These are encouraging results for a system in an early demonstration phase because significant improvement is possible in all of these performance measures. Specific suggestions for improvement are included in this document.

"Runway incursions are a persistent problem in airport ground-movement operations. Numerous critical conflicts and several fatal accidents have occurred as a result of unauthorized or otherwise inappropriate entry of aircraft or surface vehicles onto an active runway. Many of these conflicts developed quickly, leaving little time for effective intervention by either the controller or the pilots involved. A reliable system of automatic runway-status lights would be an effective way to prevent such time-critical incursions. The runway-status light system (RSLS) at Boston's Logan International Airport is an off-line proof-of-concept technology-demonstration system designed to show that automatically operated runway-status lights can promptly and reliably transmit runway-status information to pilots and surface-vehicle operators, thereby preventing unsafe runway entry or unsafe takeoff. The demonstration system does not include actual lights on the airport surface but has relied instead on an illuminated airport model board, which has allowed system development to proceed in a realistic operating environment of live airport traffic without interfering with airport operations. The results of an initial proof-of-concept assessment indicate that the system performs well, even though it is an early prototype. Missed-detection and false-alarm rates are low, and interference with normal airport operations promises to be negligible. The demonstration has shown the technical feasibility of a system of automatic runway-status lights.
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