ARC 2000: the automated air traffic control adventure

Between 1988 and 1993, the EUROCONTROL Experimental Centre (EEC) developed ARC 2000, an entirely automated air traffic control concept and demonstrator. Too far ahead of its time, the programme was abandoned, but it has paved the way for other modern air traffic management tools and applications in operation today.

As all the figures show, air traffic has been growing at a rate of 5% per annum since 1947. For air traffic controllers, this means increasing numbers of conflicts to be resolved between aircraft (conflict = aircraft which are too close to one another). Jean-Pierre Nicolaon, a former operational manager of the ARC 2000 project, recalls “generally speaking, at the time, humans were considered capable of handling five (+/- 2) problems at any one time, so progress in data processing and computing offered great prospects.

The end of the 1980s saw a great leap forward in technology. In particular, aircraft started to be fitted with flight management systems (FMS), which provided high-precision guidance. An FMS allows an aircraft’s entire flight path to be accurately calculated, meaning that it has to follow a series of three dimensional waypoints to be crossed at specific times until it reaches its destination. “The assumption was that it would be possible to predict exactly where any aircraft would be at any time and hence avert any conflicts in advance by automating control.

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Conflict prediction and resolution

The EEC then mobilised 11 people. As Jean-Pierre Nicolaon enthusiastically recollects, “we worked on the basis of a volume of air traffic three times greater than that at the time, creating more than 500 aircraft trajectories reaching a peak of 300 instantaneous flights and more than 200 conflicts in all types of conditions. The system was capable of independently resolving any conflict 45 minutes in advance – 20 minutes in the case of unforeseen event or weather conditions – compared with 6 to 8 minutes time span for the human i.e. controllers.” ARC 2000 was a means of maintaining air traffic safety levels despite the increase in traffic volume, and also allowed major fuel savings by optimising flight paths.

Too far ahead of its time, not without technical difficulties, and deemed utopian, the project was abandoned in 1993. However, it was decided to take the best from the project and build on early promising spin-offs (e.g. the HIPS* algorithm). Today, a derivative of the HIPS algorithm is still part of another system dedicated to conflict resolution, and is used by the main UK control centre. ARC 2000 applications are also present in the SESAR** European research programme, the aim of which is the construction of a single harmonised European airspace by 2020.

* HIPS: Highly Interactive Problem Solver

** SESAR: Single European Sky Air Traffic Management Research