Night Optimal Way to Land

I see, I see… Air traffic controllers predict the future using the Trajectory Manager

The aircraft makes a smooth descent towards the runway. At the correct altitude, making the least possible noise for local residents. It’s not that difficult. Any modern aircraft can do it. At least, they can as long as there are no other aircraft in the air that the air traffic control has to be taken into account. And that is unfortunately a rare occurrence! How can we enable a Continuous Descent Approach if there are potentially several aircraft in each other’s way?

Can we look into the future?

That was the question Evert Westerveld, KDC manager at LVNL, asked himself: “How can air traffic controllers ensure sufficient distance between aircraft at the point in airspace where they merge aircraft on the approach route? And can the controller do that well before the aircraft approaches the merge point? How can you predict what the distance will be 20 minutes later to an accuracy of less than 30 seconds, irrespective of wind conditions?  

This has been possible since February 18, 2016!

Since that date, together with Boeing and the Royal Netherlands Meteorological Institute (KNMI), LVNL has been conducting trials during the night within the KDC framework using the Boeing Trajectory Manager. These trials have shown that the Trajectory Manager predicts the time at which each aircraft arrives at the merge point. And to an accuracy of as small as 30 seconds. To do so, the Boeing Trajectory Manager is fed by high-resolution wind data provided by the KNMI. And this is while the aircraft is still outside AMS FIR at cruising altitude.  

Thanks to the assistance of the Trajectory Manager…

This assistance is sorely needed. During the relatively quiet night period a great deal of traffic arrives from different directions and in quick succession. This traffic all has to be guided to the correct routes in order to be able to land. At night, the traffic flies a Continuous Descent Approach (also known as CDA) from the merge point. Air traffic controllers may not influence the traffic further while it is over land.  

…aircraft no longer need to circle over the sea

Without the Trajectory Manager, air traffic controllers regularly have to create vectors over the sea in order to guarantee the correct distance between aircraft (see figure below). Using the Trajectory Manager, the traffic can be influenced at an earlier stage via the neighbouring air traffic control centres or when they enter Dutch Airspace. Aircraft can subsequently descend towards the runway without further interference.

We are very pleased!

Alina Zelenevska, project leader at LVNL, is enthusiastic about the initial results: “We have now conducted 12 trials. And we can conclude that even on busy nights (with 24 flights an hour) the accuracy of the predictions remains within 30 seconds. Aircraft can adhere to their approach routes without further interference. This yields benefits in fuel consumption and reduces the workload for the air traffic controllers and pilots. We are very pleased with this new tool, which in the first instance only is available for the night. The challenge of creating an operational system out of it is high on our list of priorities!”


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