Performance Based Communication and Surveillance (PBCS) merges two important concepts: Performance Based Communication (PBC) and Performance Based Surveillance (PBS). These terms describe communication and surveillance based on specific performance standards used in air traffic services. The North Atlantic (NAT) airspace faces challenges due to increasing traffic, making it a capacity bottleneck. To address this, new technologies and procedures, including PBCS, aim to reduce the minimum lateral and longitudinal separation between aircraft, ultimately enhancing NAT airspace capacity.
In the NAT High Level Airspace (HLA), PBCS follows RCP 240 and RSP 180 specifications. This allows for reduced separation minima of 55.5 km (30 nm), 93 km (50 nm), and 5-minute longitudinal separations, as well as a 42.6 km (23 nm) lateral separation minimum. To maintain safety and efficiency in ATM operations within the NAT HLA, performance-based operations and monitoring protocols have been put in place. The previous Reduce Lateral Separation and Reduced Longitudinal Separation trials are now replaced by PBCS criteria.
Monitoring includes the performance of FANS 1/A (and equivalent), Controller Pilot Data Link Communications (CPDLC), and Automatic Dependent Surveillance – Contract (ADS-C) in the NAT HLA. These are evaluated against the Required Communications Performance (RCP) 240 and Required Surveillance Performance (RSP) 180 standards. As of March 2018, flights must indicate compliance with these specifications to qualify for reduced separation minima. Currently, this program is limited to reduced separation tracks at the center of the Organised Track System (OTS), but plans to expand it across the entire NAT HLA are underway. Future compliance with RCP and RSP is anticipated in other airspaces as well.
The RCP 240 and RSP 180 specifications are crucial for PBCS in the NAT HLA. RCP specifications outline the communication performance requirements assigned to system components based on the needs of specific operations within a given airspace concept. Key requirements include maximum transaction time, continuity, availability, and integrity. For RCP 240, the requirements are a maximum transaction time of 240 seconds, 99.9% continuity, 99.99% availability, and an integrity of 10^-5.
Similarly, RSP specifications define the surveillance performance needed for system components. These include a maximum data delivery time of 180 seconds, 99% continuity, 99.99% availability, and an integrity of 10^-5.
Requirements for obtaining National Aviation Authority (NAA) approval for operations in PBCS airspace can differ among regulators. Generally, the following criteria apply:
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Aircraft: The RCP 240 and RSP 180 Special Authorization is unique to each airframe. Aircraft manufacturers or suppliers must demonstrate compliance with RCP 240 and RSP 180 according to ICAO’s Performance-based Communications and Surveillance Manual (Doc 9869). They also need to show that the aircraft meets the time, continuity, availability, and integrity criteria, provide alerts for system failures, and list PBCS capabilities in the master minimum equipment list (MMEL).
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Operator: Operators must ensure that flight crews are trained in PBCS operations, including normal and alert-related procedures. They must confirm that the aircraft system is approved for use under RCP 240 and RSP 180 standards and that proper maintenance is conducted.
