Airborne and Ground Information for Lateral Spacing during Closely Spaced Parallel Approach Operations

The AILS (Airborne Information for Lateral Spacing) system can increase the efficiency of airports in Instrument Meteorological Conditions (IMC) by allowing independent, parallel approaches to runways as close as 2,500 feet. The proposed AILS system consists of advanced conflict detection algorithms, flight deck displays, resolution procedures, and a set of airspace procedures to assist with such closely-spaced, independent approaches to parallel runways. The goal of this research was to explore and resolve potential human factors issues that might arise if the AILS system were implemented. This study examined flight crew and ATC interactions during independent closely spaced approach operations (CSPA). Twelve B-747 flight crews conducted AILS approaches to parallel, closely spaced runways at Seattle-Tacoma airport. During 75% of the approaches an aircraft blunder and breakout was conducted. Flight crew workload and performance data were collected using both objective and subjective assessment methodologies. However, ATC performance and workload data were not collected. Data from the study suggest that with appropriate airspace and flight deck systems, closely spaced approach operations can be conducted safely. However, additional research is needed to assess conditions where crews responded slowly to AILS alerts.