Trajectory-based operations are one step closer

Airplane contrails

Trajectory-based operations or TBO, will allow Air Traffic Management systems to know, and if required, to modify planned and actual trajectory of a flight before or during its operation. This accomplished is via accurate information that is shared with all stakeholders. The goal is to achieve efficiency gains for both individual aircraft and the network as a whole.

As a step towards this goal, SESAR members NATS and Indra have completed research into a capability which facilitates the generation of route changes and clearances, reducing the chances of mistyped instructions and paving the way for more complex free route operations in Europe.

Today, controllers create a controller-pilot data-link communications (CPDLC) route change instruction by typing waypoint names or selecting them from a route menu. A bespoke, non-published waypoint is more complex in its definition, requiring up to 15 digits to define a point by latitude/longitude. Manual entry of such a complex clearance is judged not feasible due to high workload and the possibility of input error. Controllers currently limit route amendments to published waypoints.

In the future, flights in en-route airspace will largely be free route, with very few published waypoints in their flight plan. Flight plans will instead consist of user-defined, bespoke waypoints defined as lat/long pairs, and which may be widely-spaced. In this environment, the use of lateral interventions to resolve separation conflicts may require an instruction to resume own navigation to a latitude/longitude non-published waypoint.

Indra and NATS investigated the capability to create route change through interaction with a graphical interface on the controller workstation, and system-generate a corresponding complex clearance with no typing required. The solution will help controllers more efficiently manage traffic in a free route environment. More specifically, the solution is expected to help maintain the separation management flexibility of heading instructions that exists in today’s operations as we move to free route operations, and the ability to keep aircraft on closed-loop clearances, increasing the value of planning trajectories. The concept was positively assessed by controllers, who confirmed that the use of latitude/longitude would be particularly valuable within a free-route environment.

This work has received funding from the SESAR Joint Undertaking under the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 734161.