ATS B2 ADS-C

Automatic Dependent Surveillance Contract (ATS-B2)

MUAC starts operational use of ATN Automatic Dependent Surveillance-Contract

ATS B2 Automatic Dependent Surveillance - Contract (ADS-C) has been operational at EUROCONTROL’s Maastricht Upper Area Control Centre (MUAC) since 30 May 2022. It is a datalink-based technology which allows different types of information to be obtained directly from the aircraft’s flight management system, without pilot interaction.

It enables aircraft to automatically establish an ADS-C connection and downlink key aircraft intent to the MUAC system, such as:

  • extended projected profile;
  • aircraft position;
  • altitude;
  • speed;
  • elements of navigational intent; and
  • meteorological data.

This is then displayed on air traffic controllers’ screens, and enables MUAC to offer aircraft operators enhanced air navigation services thanks to improved flight predictability.

ADS-C is a major step towards trajectory-based operations, offering controllers a clearer picture of aircraft intentions and sector loads. It is one of the first steps towards future automation, with reduced fuel costs, fewer emissions, improved safety and more efficient air navigation services.

The benefits of ADS-C are far-reaching and are felt by a broad range of actors, from individual aircraft operators to air traffic controllers, as well as by the network as a whole.

ADS-C puts MUAC in a better position to make accurate and earlier predictions, resulting in smoother, safer, more sustainable and more efficient flights. Furthermore, with ADS-C, aircraft operators’ preferred trajectories are taken into account. Air navigation efficiency is improved through greater awareness of flight plan trajectories beyond MUAC’s airspace boundaries, flight plan changes, top of climb and top of descent indications, and cruising level indications at the most optimal times.

Improved air navigation efficiency

Using ADS-C, MUAC can therefore better predict traffic loads, which improves the efficiency of operational planning and reduces the need for flow management procedures.

It provides a greater awareness of flight plan changes, even those not received in advance by the system.

Optimised climb and descent profiles: automatic top of climb and top of descent indicators may result in smoother, managed mode climb and descent. In the event of a lateral discrepancy between the air and ground-predicted trajectories, automated warnings are displayed.

Screenshot showing an example ToC climb performance estimation
Screenshot showing an HMI EPP example descend latvert

Airlines are more likely to receive earlier direct routeings and requested levels, cruising level adjustments at the most optimal times (as pilots do not need to request them), and fewer speed restrictions on conversion thanks to the controller’s knowledge of their planned speed.

Enhanced safety

Thanks to the ADS-C information, the ground system can automatically check the trajectories and flag discrepancies, saving time on the radio frequency and helping to reduce the likelihood of a mistake. Downlinked routes are automatically checked against what is expected on the ground side, and in the event of discrepancy, a 2D discrepancy warning is displayed. This provides protection against certain human errors, like misinterpretation of a route clearance.

FMS loadable complex clearances have more clarity, which helps reduce human error.

Future plans include medium-term conflict detection which will also be fed with ADS-C values for improved safety.

Reduced fuel consumption

ADS-C reduces fuel consumption by helping controllers chose the most efficient route, providing information (on request) of the earliest time over a fix. This can help the aircraft stay on a direct track even if a military area becomes active in the meantime. System support showing exit times from military areas, top of descent displays, and descend when ready CPDLC clearances can help aircraft fly the shortest, greenest and most efficient route for as long as possible.

Top of climb displays allow controllers to better estimate climb performance, possibly resulting in earlier direct routeings, fewer miles flown and earlier clearances to the requested level.

Top of descent displays enable aircraft to start their descent later than usual, increasing the number of minutes spent at the cruising level and (depending on the traffic), resulting in more continuous descents.

Cross point at time CPDLC clearances could improve initial sequencing (cross-border arrival management or XMAN), reducing fuel consumption.

Better predictions of runway occupancy time

The data collected by ADS-C helps improve the cross-border arrival management (XMAN) algorithm for high-density aerodromes, improving the accuracy of time-over-point and speeds.

Increased accuracy of time-over-point and speeds, and extended XMAN and AMAN operations provide much higher en-route delay absorptions whilst at the same time reducing fuel usage and CO2 emissions.

Greater synergies between aircraft operators and air traffic control

As the aircraft intent is automatically downlinked to the MUAC system, fewer requests and interventions are needed by the pilot, resulting in more efficient and seamless communication.

Cruising level adjustments are sent automatically, with no need for the pilots to request them.

By using trajectory-based operations and the 2D discrepancy indicator, ADS-C improves situational awareness, reduces human error and increases air navigation efficiency. Air traffic controllers receive a more accurate picture of aircraft intentions, while visual displays of top of descent, top of climb, and cross-over speeds help refine air traffic management, in particular flight predictability.

Reduced human error

ADS-C helps to prevent human mistakes from going unnoticed – for example, owing to a wrongly implemented route clearance – whilst also saving time and improving overall efficiency.

Automated warnings are displayed when a 2D discrepancy is detected between the air and ground predicted trajectories. ADS-C can also help in the event that a flight can exit a military area before it becomes active, enabling pilots to confidently take the shortest route.

Improved situational awareness and safety

Thanks to the display of the aircraft’s extended projected profile (EPP) trajectory as well as the 2D discrepancy indicator, air traffic controllers have a more accurate picture of aircraft intentions and sector loads.

Better air traffic management

The display of the top of climb and top of descent allows air traffic controllers to facilitate continuous descent operations when traffic allows it.

Screenshot showing an example ToC climb performance estimation
Screenshot showing an HMI EPP example descend latvert

This enables the descent to be undertaken in fewer steps, increasing the number of minutes spent at cruising level, as well as the number of step descents.

Greater synergies between aircraft operators and air traffic control

As the aircraft intent is automatically downlinked to the MUAC system, fewer requests and interventions are needed by the pilot, resulting in more efficient and seamless communication.

Cruising level adjustments are sent automatically, with no need for the pilots to request them.

Implementation of ATS B2 ADS-C

ADS-C has been in operation at MUAC since May 2022, enhancing air navigation services for aircraft operators which are:

  • ATS B2-equipped: CPDLC v2 and ADS-C;
  • registered on the EUROCONTROL log-on list for CPDLC and on the list of ADS-C usage in the MUAC area of responsibility.

The higher the number of aircraft equipped with ADS-C, the broader the benefits – both at an individual and network level.

Contact us

For further information on ADS-C operations please contact us at [email protected].