Automatic Dependent Surveillance – Broadcast

To pave the way for the transformation of the European surveillance infrastructure towards the less costly and more spectrum efficient ADS-B technology, Airspace Users operating in EU airspace with airplanes of more than 5.7 tons maximum certified takeoff mass (MTOM) and maximum cruising true airspeed capability greater than 250 knots (KTAS) have been mandated by European Commission per Commission Implementing Regulation EU No 1207/2011 (SPI IR), amended by EU No 1028/2014 and EU 2017/386 to implement SPI IR compliant avionics, including ADS-B version 2 (according to EASA CS-ACNS and EUROCAE ED-102A) before June 7th 2020. The mandate applies to all GAT/IFR flights within the EU airspace, including operators whose state of registry is outside of the EU but operate into or across the EU airspace.

The European Commission tasked SESAR Deployment Manager (SDM) with the planning and execution of a coordinated and synchronized aircraft and ground implementation of ADS-B. In response to this request SDM produced the ADS-B Implementation Plan, the first edition of which was delivered and published in December 2018. SDM partnered with EUROCONTROL which supports the activity, by, amongst others, performing the operational and technical coordination, feedback from its NM performance monitoring on ADS-B as well as contributing to the preparation of the activity deliverables

On the basis of extensive surveys and interaction with EU-based operators, maintenance facilities, equipment vendors and aircraft manufacturers, the Plan showed that 70–75% equipage rate could be achieved in the EU registered, SPI-IR mandated fleet by the compliance deadline June 7th 2020.

A cursory review of the diagram above will reveal that even the best effort possible will leave a substantial proportion of the fleet not compliant with the rule on the compliance deadline June 7th, 2020.

In recognition of the complexity and the nature of the underlying causes, the European Commission tasked EASA with drafting of a commensurate transitional regime in the form of an exemptions policy and an associated application process.

The exemption policy is expected to be published in the latter half of 2019.

SESAR Deployment Manager prepared input to support the definition of the potential exemption policy. A key part was based on a survey which addressed 70 of the major EU airlines, comprising around 47% of the mandated EU fleet. The analysis was restricted to retrofits only and identified three main groups as candidates for the exemptions regime:

• The “Late implementation” group, comprising aircraft that are planned for fitment but can only reach the deadline with disproportionally high effort or are limited by Service Bulletin or STC availability, parts availability or workshop capacity and scheduling constraints. SESAR Deployment Manager estimated the magnitude of this group at approximately 17% of all EU registered airframes. A tightly ring-fenced transition period extending beyond the compliance deadline of June 7th 2020 will provide a much needed respite to operators and allow them to insert the implementation of ADS-B in their regular maintenance schedules.
• The “Phase out” group, comprising aircraft that are anticipated to cease operations in EU airspace before substantial operational use of their planned ADS-B capability by ground systems could be expected. Consequently, airlines argue that requiring their fitment violates the principle of proportionality. The estimated volume of this group is around 10% aircraft. SESAR Deployment Manager expects that some migration of aircraft will occur between these two groups as airlines continually adjust their fleet planning strategies.
• The “Onboard architecture” group, comprising odd onboard architecture configurations where the fitment of a compliant solution is financially prohibitive or technically unfeasible. In rarer cases there in no solution defined. SDM estimated the volume of this fleet at around 3% airframes and shrinking.

SESAR Deployment Manager input to the exemption policy is summarized in the figure below:

There are numerous ADS-B mandates anticipated or already in place in many parts of the world. The map below shows in green regions requiring at least ADS-B version 0, in dark blue the ones requiring ADS-B version 2, together with the anticipated date of entry-into-force, and in grey where regulatory activity is ongoing and mandates are expected in the near future. Note that the map will be regularly updated as new information becomes available.

The EU Air Navigation Service Providers (ANSPs) have reported a substantial ADS-B sensor coverage in Europe available from ground based systems; primarily from combined WAM/ADS-B systems but also ADS-B only Ground systems. ADS-B capable radars as well as space-based ADS-B coverage are expected to make a substantial contribution towards a global ADS-B coverage in the coming years.

Having secured coverage, the ANSP will next proceed to integrate ADS-B data in its surveillance chain; this integration in the EU ATM systems is currently limited, with ANSPs citing aircraft ADS-B equipage, ADS-B performance and regulatory concerns as the necessary conditions to be resolved. However, a majority of EU based national ANSPs have at least some plans in place to proceed with integration in the near future, given the availability of a sufficient aircraft equipage ratio. SDM believes that those concerns will be addressed and resolved adequately as ADS-B implementation progresses.

If the integration is properly synchronized across domains and supported by a competent programme to catalyze ground investment plans, many ANSPs indicated their willingness to commit to technical and operational integration activities that could use the ADS-B sensor coverage across the vast majority of the continental airspace as early as 2023.

The primary use-case for ADS-B in the complex and traffic heavy European airspace is that of a complementary sensor to independent surveillance. In that role, ADS-B will open up substantial rationalization potential in the very dense European network of secondary radars. The use of ADS-B as sole means will occur in specific environments, characterized by low traffic density and/or lack of independent alternatives. This use case has already been successfully deployed operationally in a number of locations; the ICAO NAT region is a prime deployment location for sole-means ADS-B.

It is evident that a strong momentum to progress with ADS-B deployment exists in both the airborne and the ground domain. A harmonized ground and air deployment programme is important to synchronize and catalyze these efforts, to ensure that substantial ADS-B operational use is commonplace in Europe from mid 2020s.