4D trajectory management

Improving flight management through harmonised and collaborative flight trajectory definition, and sharing this information with all ATM stakeholders.

The SESAR 4D trajectory management (PJ18 4DTM) project will contribute to harmonised, global collaborative trajectory information definition/sharing (ground – ground, air – ground) in order to obtain a unique and integrated view of all flights trajectories (including military ones) for air traffic management (ATM) stakeholders.


Harmonised and global trajectory information definition/sharing, including improved negotiation mechanisms, will bring significant operational benefits to flight management.

PJ18 4DT will:

  • make for increased predictability, more efficiency, better human performance and enhanced flexibility;
  • enable the optimal use of ATM resources (human, airspace, environment);
  • lead to the faster resolution of issues with the least disruption to traffic;
  • underpin collaborative solutions;
  • provide a single/shared, updated and complete view of the ATM environment (flight trajectory, airspace, meteorological and network data).

Our role

Together with several ATM stakeholders, we are developing the operational concept and carrying out real-time simulations (RTS) to validate the associated operational elements, gathering inputs and building consensus among partners.


Trajectory revision using datalink (PJ18-2a)

The trajectory-based operations (TBO) concept consists of improved trajectory negotiation mechanisms (during the flight execution/planning phases); it entails giving more complex clearances to the aircraft before it enters a given sector or centre. The operational concept development includes defining collaborative operational procedures and operational requirements to reach harmonised/global trajectory data definition/sharing in both nominal and non-nominal ATM conditions.

The main purpose of RTS is to investigate how route clearances provided in advance by the planning controller can help reduce the executive controller’s workload and ensure that the air and ground predicted trajectories are consistent, making for a more precise picture of traffic expected. Implementing it will involve integrating the air traffic control (ATC) real-time simulator and aircraft cockpit simulators from several aircraft/cockpit manufacturers. The RTS assessment will focus mainly on:

  • the impact on air traffic control officers’ (ATCOs) tasks and workload and the impact on flight deck operations;
  • ATCO/pilot interactions with improved air/ground collaboration using controller-pilot datalink communications (CPDLC);
  • pilot working methods optimisation;
  • the feasibility of technical requirements.

Flight object interoperability (IOP - PJ18-2b)

Through the IOP solution, stakeholders will exchange a flight object (FO) and a complete set of data (e.g. flight plans, restrictions, STARs, etc.) through a unique protocol and exchange format.

IOP mechanisms have provided a continuous flow of updated information since the first FO was published. The SESAR 2020 experiments will set up a validation test bed involving five ATC Units in the core area and include major European ATC equipment manufacturers. The purpose of this validation is to confirm the feasibility of the proposed interoperability standard and to evaluate the benefits for air traffic controllers in sectors situated at the boundaries of other centres.

The target validation of the basic IOP is June 2020; deployment will take place between 2025 to 2027.

Improved aeronautical (AIM) and meteorological information (18-04a and 18-04b)

Solutions 18-04a (AIM) and 18-04b (MET) focus on improving the exchange of aeronautical and meteorological information, as well as its quality, consistency and usability.

These solutions aim to improve the provision of aeronautical and meteorological information by defining and delivering verified new or enhanced AIM and MET information services, as well as the associated system capabilities.

These services and underpinning capabilities support other relevant solutions in the SESAR 2020 industrial research programme - and trajectory operations in general - by providing the requisite AIM and MET information. They also support these solutions by demonstrating the benefit of integrating the best available fit-for-purpose AIM and MET information.

EUROCONTROL is leading these solutions to:

  • ensuring the provision of aeronautical data services for enhanced vision systems;
  • improving the digital NOTAM service through the introduction of new filtering possibilities and the inclusion of additional information from digital NOTAM, such as the list of impacted planned flights.

As part of PJ.18-04b solution, we are developing operational procedures for information generation, as well as the associated system capabilities, including the required SWIM-based information service. 

AIM and MET information service in the cockpit (18-04c)

Solution 18-04c focuses on the acquisition, processing and distribution of AIM and MET information and the representation of this information to airspace users.

Later goals include the operational validation of enhanced situational awareness, improved strategic trajectory management and improved collaborative decision-making, based on supported airspace user participation in these processes. EUROCONTROL is leading this solution to improve:

  • the flight crew’s situational awareness of the current and planned/forecasted status of infrastructure available by integrating AIM and MET information in the aircraft information domain  to increase safety and support flight efficiency;
  • flight efficiency by optimising onboard trajectory prediction by integrating high quality, up-to-date AIM and trajectory specific MET information on the flight deck.

This solution integrates enhanced aeronautical and meteorological information as well as the underpinning capabilities developed by solutions PJ 18-04a and b.

Improved trajectory predictions based on improved air/ground exchanges (18-06 & PJ31)

The main objective is to demonstrate that the trajectories computed by the aircraft’s avionics can be downlinked and used by ground ATC systems. To that end, about 100 A320 aircraft from major European airlines will be equipped with the new avionics, while various ANSPs (DFS, ENAV, MUAC and NATS) and the Experimental Centre of Brétigny (EEC) will deploy the requisite infrastructure to downlink, collect and use the trajectories.

Aircraft will be progressively equipped from March 2019 until October 2019, and data transmitted by ADS-C will be recorded for analysis. First results are expected at the end of 2019, and the project will be completed in June 2020.


PJ 18-2a: Airbus, Dassault, Honeywell Skyguide, Leonardo


PJ18-04 : Airbus, Austrocontrol /COOPANS, DLR (AT-One), Croatia Control /COOPANS, DFS/Lufthansa System, DSNA, ENAV, Frequentis, Honeywell, Leonardo, Thales Air Sys, Thales Avionics, LPS SR (B4), PANSA (B4)

PJ18-06 & PJ 31: Airbus, DFS, ENAV, NATS