Potential Operational Consequences of the Use of ACAS Xu in Controlled Airspace

抄録

A “detect-and-avoid” capability providing a “remain well-clear” function will be needed for unmanned aircraft to fly safely in uncontrolled airspace. It could also be used in controlled airspace provided that the action chosen by the pilot, based on the system suggestive guidance, is compatible with the current air traffic control clearance or an amended clearance. The study reported in this paper looks at the potential operational consequences of the interaction between a pilot and the air traffic controller in controlled airspace when a clearance amendment must be requested by the pilot using the recently standardized detect-and-avoid system, Airborne Collision Avoidance Systems Xu (ACAS Xu). Numerical simulations on a potential encounter are performed. A model of pilot behavior when faced with a remain well-clear alert (including pilot-controller communication delays) is used. An analysis of the qualitative results outlines several areas of concern: the possible confusion caused by multiple changes in remain well-clear guidance, the undesirable effects when both aircraft are equipped with ACAS Xu, and the potential interaction with short-term conflict alerts displayed at the air traffic controller’s workstation.