Improving Surveillance of Clearances in Future Air Traffic Control Systems

Abstract

*† ‡ § Analysis of Air Traffic Control (ATC) system processes has identified the importance of accurate information regarding the active clearances for individual aircraft. The development, communication and execution of clearances involves many different agents that reside in the system, including controllers, ground automation systems, flight crews and aircraft automation systems. Inconsistencies between any of these agents in the understanding of the clearance for any given aircraft can lead to adverse safety, security or efficiency implications. For example, conflict detection and resolution tools require an accurate representation of the trajectory to be flown by each aircraft within the system. Additionally, improving conformance monitoring in ATC to enhance safety and security relies on accurate information of the clearances making up any given aircraft's Conformance Basis. Examples of clearance inconsistencies observed in the ATC system are presented. Models are developed to describe the different types and causes of inconsistencies that can occur, including temporal mismatch, insufficient or incorrect data entry into automation systems and voice communication misunderstandings. The occurrence of these inconsistencies can be reduced by employing advanced technologies such as improved human/machine interfaces, use of datalink and voice recognition technologies that enhance the “surveillance” of clearances and automate the sharing of data among systems. Some of these technologies are already being implemented through the continuing evolution of the ATC system. Upgrades to the sector Display System Replacement (DSR) and the deployment of the User Request Evaluation Tool (URET) promote the entry of clearance information into the ATC system through interfaces that rely on interactive menus rather than keystroke entries, thereby reducing data entry workload. The scheduled implementation of the En Route Automation Modernization (ERAM) architecture along with a system wide information management system will facilitate the use of common data across subsystems within the ATC system. Controller Pilot Data Link Communications (CPDLC) coupled with other ATC decision support systems should further reduce controller data entry workload and voice communication misunderstandings through clearance uplink capabilities. In the longer term, the exchange of intent data between the aircraft and the ATC system offer the possibility of achieving still greater information accuracy, while the use of automated speech recognition technologies may reduce workload and improve clearance capture still further. Each of these approaches is described in detail.