1.1.1. This Circular aims to inform Brazilian airspace users about DECEA's planning for the implementation of the Performance-Based Communication and Surveillance (PBCS) concept, with a view to reducing the horizontal separation minima in the Atlântico FIR (SBAO).

1.2.1. The information contained in this AIC is applicable to the Atlântico ACC (ACC-AO), the aircraft operators that evolve in the SBAO FIR and the aeronautical community of interest.

2.1.1. The PBCS concept, established by ICAO in Doc 9869, applies to air traffic control and establishes technical-operational parameters to enable the use of different communication and surveillance technologies available in aviation, according to their respective performances.

2.1.2. Performance-Based Communication and Surveillance (PBCS) is aligned to Performance-Based Navigation (PBN). While the PBN concept applies Required Navigation Performance (RNP) and Area Navigation (RNAV) specifications, the PBCS concept presents Required Communication Performance (RCP) and Required Surveillance Performance (RSP) criteria.

2.1.3. Compliance with the RCP and RSP specifications for the PBCS depends on the conformity of the various elements that make up the communication and surveillance systems involved. Figure 1 shows the performance-based CNS/ATM model.

2.2.1. Meeting PBCS requirements allows the evolution of air traffic management (ATM) operations, supports the use of new standards, procedures and the reduction of separation minima currently employed in remote regions.

2.2.2. This concept provides a framework in which all interested parties (regulators, air traffic service providers, operators, communication service providers and manufacturers) continuously collaborate in optimizing the use of airspace.

2.2.3. The technologies employed are Controller-Pilot Data Link Communication (CPDLC) and Automatic Dependent Surveillance - Contract (ADS-C).

2.2.4. In the context of PBCS, the navigation capacity (RNP) of aircraft plays an important role, as it will indicate how much the horizontal separation minima can be reduced and, thus, how much the benefits will be enhanced.

2.3.1. ACC-AO provides air traffic control, flight information and alert services in the SBAO FIR, using CPDLC and HF communications, in addition to aircraft monitoring through ADS-C.

2.3.2. The minimum longitudinal separation used in the SBAO FIR is 10 minutes or 80 NM between aircraft at the same flight level, in the same direction and at the same speed. For traffic on intersecting routes, at the same level, the longitudinal separation between aircraft is 15 minutes. The applied lateral separation is at least 50 NM.

2.3.3. In the portion of the SBAO FIR, close to the equatorial region of the globe, there is a set of airways that channel flights between Europe and South America, in both directions, known as the EUR/SAM Corridor. It is in this region where there is the largest flow of aircraft traffic, more than 73% of all AO FIR traffic.

2.3.4. The EUR/SAM Corridor crosses the Intertropical Convergence Zone (ITCZ). The corresponding airspace is periodically affected, between the months of March and May, by climate instability, clusters of Cumulonimbus (Cb), intense precipitation and areas of turbulence, causing significant route deviations.

2.3.5. The separations applied limit the capacity and flexibility of airspace and the use of routes.

3.1. To operate under the PBCS concept, the ATC system, the data link system, the aircraft systems and operators must continuously comply with functional, safety and performance requirements described in the specifications for communication and surveillance systems, according to Doc 9869 – PBCS Manual.

3.2. Performance requirements are defined in terms of RCP (Required Communication Performance) and RSP (Required Surveillance Performance). They indicate the levels of reliability, availability, latency and integrity of communications and surveillance.

3.3. Navigation requirements are defined in terms of RNP (Required Navigation Performance), which indicates the level of accuracy, integrity, continuity and functionality of navigation systems.

NOTE: Detailed information on PBCS eligibility and operational employment will be set forth in specific regulations.

3.4. The application of the PBCS concept will enable:

a) the reduction of the separation minima between aircraft and the increase in airspace capacity, the optimization of routes and the expansion of the offer of levels more adjusted to aircraft performance;
b) the increase in the flexibility and adaptability of operations in the face of meteorological impacts, allowing dynamic adjustments to air traffic;
c) the reduction of fuel consumption, pollutant emissions and operating costs, contributing to environmental and economic sustainability;
d) keeping safety levels, through monitoring processes and the use of alerts in air traffic control software; and
e) the operation of aircraft with different performances, without the need for airspace segregation, in alignment with ICAO concepts.

Note: The perception of these advantages will be enhanced as the percentage of aircraft capable of meeting communication, navigation and surveillance requirements increases.

4.1. The reduction of horizontal separations between aircraft that meet the established communication, navigation and surveillance requirements will occur in two phases in the SBAO FIR, as follows:

a) Phase 1: 5 minutes longitudinal and 50 NM lateral, starting in December 2025; and
b) Phase 2: 30 NM longitudinal and 23 NM lateral, starting in April 2026.

NOTE: In this phase, the ADS-C Climb and Descent Procedure (CDP) will also be implemented, which will allow the reduction of longitudinal separation between aircraft during route crossings, with parameters set out in ICA 100-37, item 4.3.12.13.

5.1. DECEA provides a communication channel for you to send questions, suggestions, comments, criticisms, praise and error notifications through the Citizen Service Center at the following address: http://servicos.decea.gov.br/sac/index.cfm, selecting the option CONTACT US the Area menu.

5.2. Cases not provided for shall be settled by the Head of the DECEA’s Subdepartment of Operations.

5.3. This AIC republish the AIC A 11/24.