This month will mark a turning point from the “pioneer” phase to the mandate phase of Europe’s implementation of automatic dependent surveillance-broadcast (ADS-B) for aircraft tracking and separation.

The Single Sky Committee of the European Commission, representing member states and Eurocontrol, is expected to approve the Surveillance Performance and Interoperability Implementing Rule (SPI-IR) identifying surveillance system performance and ground and airborne interoperability requirements for ADS-B this month. The rule should be published by year-end in the Official Journal of the European Union.

The SPI-IR is a “critical point” dividing the pioneer phase, in which 18 airlines fly some 500 aircraft certified with ADS-B out functionality in non-radar airspace, and the coming ADS-B mandate, said Christos Rekkas, head of Eurocontrol’s Cascade program, which is coordinating the European implementation of ADS-B. In Europe, ADS-B capability will be required for forward-fit aircraft by January 2015, for retrofit application by December 2017. ADS-B out the broadcast of aircraft position reports to the ground, will be required in the U.S. by 2020.

ADS-B provisions of the European rule apply to aircraft with an mtow of more than 12,566 pounds (5,700 kg) or with a cruising speed of more than 250 knots, including those operated by international carriers. The mandate does not cover smaller aircraft. “This subset of the fleet can be covered by future local mandates (for example, defining parts of the local airspace where even smaller aircraft will have to comply with the rule) or perhaps a Europe-wide further rule extending the applicability of the ADS-B mandate to all aircraft or in defined airspace,” Eurocontrol stated in response to a query from AIN.

Aircraft flying IFR as general air traffic (GAT) must be equipped with mode-S transponders compliant with the updated DO260B/ED102A standard, transmitting 1090 MHz extended squitter (ES) position reports. Transponders must be integrated with a global navigation satellite system (GNSS)-based position data source. ADS-B capability adds to existing European requirements for mode-S elementary (ELS) and enhanced (EHS) capable transponders to answer secondary surveillance radar interrogations.

ADS-B will be conducted in combination with primary and secondary radar and wide area multilateration (Wam) systems, or as a sole means of surveillance as approved by the European Aviation Safety Agency.

“It doesn’t have to do with airspace segregation,” Rekkas said, outlining the SPI-IR during the ATC Global conference in March. “It speaks fundamentally about the segregation with respect to the rate or the speed of the aircraft. … It affects all aircraft flying IFR/GAT. Mode-S elementary surveillance is part of it. All these aircraft have to be Mode-S elementary surveillance-equipped. In addition, they have to be mode-S enhanced surveillance equipped and ADS-B out equipped.”

In addition to proving the airworthiness of ADS-B equipment for air traffic services, the Cascade Pioneer Airline Project supported validation of ground surveillance by participating air navigation service providers (ANSPs) under Eurocontrol’s Cristal initiative. Yet the SPI-IR does not set a date for ANSP implementation of ADS-B. “Since this aircraft implementation is going to make the fleet capable of” ADS-B out position reporting, Rekkas said at ATC Global, “the ANSPs will be in a position to select the most efficient surveillance techniques to cover their operational needs.”

According to Eurocontrol, ANSPs in Sweden, Germany, the Czech Republic, Bulgaria, Greece, Cyprus and the UK will be among the first to offer air-traffic separation services based on ADS-B. Other candidates are ANSPs in Latvia, Austria, Romania, Spain and Portugal with Wam stations, also capable of routing ADS-B position reports. “We should get closer to this [2015 ADS-B compliance] date before there would be firm commitments for operational services,” Eurocontrol told AIN. “Much will depend on the numbers of ADS-B operationally approved aircraft.”

Toward More Capable Operations

With the road paved toward ADS-B out implementation in Europe, planning has been ongoing since late 2009 to certify equipment for ADS-B in applications, involving the display and exploitation of air-traffic data in the cockpit. Five airlines–British Airways, Delta, Swiss International Airlines, US Airways and Virgin Atlantic–along with ANSPs UK Nats and Isavia of Iceland are participating in the Airborne Traffic Situational Awareness (Atsaw) Pioneer Project under the Cascade umbrella. Operational trials with 25 equipped aircraft begin this year over the North Atlantic.

The aim of the Atsaw project is to validate ADS-B in applications in revenue service conditions, eventually transitioning to regular operations. Applications targeted are enhanced airborne traffic situational awareness (AIRB), in-trail procedures (ITP), visual separation on approach (VSA) and Airport Surface (Surf) movements. According to Eurocontrol, the project marks the first operational use of Atsaw applications and paves the way for deployment of other ADS-B in applications.

Rekkas, at ATC Global, said Atsaw trials will support development of a so-called Airborne CNS Certification Specification (CS-ACNS) for ADS-B in. “We don’t yet have a date for that, but it is certainly the next big target after ADS-B out,” he said.