Follow the ghost
Merging helps guide traffic to the correct routes. This applies to Dutch motorways but it also applies to our airspace. To develop smooth merging of air traffic the Netherlands Aerospace Centre (NLR) conducted the Traffic Merging Support for Schiphol Approach project from August 2016 to January 2017 in close conjunction with LVNL. The aim of the study was to test and specify a new merging support tool for night operations for air traffic controllers thoroughly such that the tool can be brought into active service.
From three to one
The aim of the merging process at Schiphol is to merge two to three separate traffic flows of aircraft on fixed approach routes from different directions into a single traffic flow (see figure 1). The support tool serves as the final check for TMA traffic controllers at Schiphol to ensure that the merge is being conducted safely. The study focused on night flights as there are as yet no fixed routes, that require merging during the day.
Figure 1: three different approach routes are merged to a single route on the way to the runway
Which criteria does this tool need to meet?
The main criteria are:
- The tool needs to be easy to use
- The tool needs to work on the basis of distances to the runway rather than on the basis of flying time to the runway
- It must be possible to incorporate the tool into the LVNL air traffic control system
- It must be easy to train personnel to use the tool; this simplifies implementation
How can we actually implement the tool?
With a view to deciding how best to implement the tool, we developed a prototype on NLR’s ATC NARSIM simulator. We then evaluated the prototype in a number of ways in order to involve as many different experts as possible in its implementation. This was done using simulations, by showing air traffic controllers film clips and by holding discussion sessions. We were consequently able to improve the tool even more.
How do we ensure broad support for the tool?
This was an important extra objective of this study. We wanted to create support not just among air traffic controllers, but also among the other LVNL departments involved. We therefore held intensive consultations with those directly involved right from the start in order to prevent technical obstacles later.
The tool works…
Air traffic controllers are unanimous about the usefulness of the support tool in their day-to-day work. This was clearly demonstrated by the study. The discussions and evaluations after the simulation sessions ensured that there was agreement on how the tool needs to work. Another important aspect was what the tool looks like. The objectives were always a priority here: the tool needs to be intuitive and easy to use, it must be easy to train others to use it and incorporate it into existing systems.
…the ghosts can start doing their job!
The responses to the study questionnaire were ultimately translated into a number of system criteria that together describe the interface and the behaviour of the tool. The combined criteria describe a tool that plots what are known as ‘ghosts’ from one route on a different route. The distance to the runway determines the position of the ghosts (see figure 2). This enables air traffic controllers to estimate accurately whether the aircraft are at a sufficient distance from one another at the merging point. This forms the end point for this study and at the same time the starting point for preparing implementation. Follow the ghost!
Figure 2: projection of a radar plot on a different route