With nearly 500,000 movements a year and four runways, Paris-CDG is one of the busiest airports in Europe. During peak hours, there is an aircraft takeoff and landing every 50 seconds. The European Wake Separation Recategorisation (RECAT-EU) has been identified as a lead project in the safety, environmental and ATC capacity domains.

The operational concept

With the modernisation of airline fleets and the recent boost in technology, ICAO wake vortex separation rules that four categories of aircraft need to be updated to streamline a number of over-conservative separations.

The EUROCONTROL agency has adapted the ICAO standards to improve runway throughput in major European platforms. RECAT-EU defines six categories of aircraft taking into account the strength and evolution of the wake turbulence generated and the resistance characteristics of the following aircraft. The two ICAO categories Medium and Heavy are divided into ‘Upper’ and ‘Lower’.

Aircraft wake data collected with a light detection and ranging radar at Paris supports these reduced minima. The European Aviation Safety Agency endorsed EUROCONTROL’s safety case report on 10 October 2014. On this basis, Paris-CDG and Paris-Le Bourget air navigation services have deployed this new standard, adapted to the aircraft mix that operate at the airports, delivering safe and more accurate separations between pairs of aircraft.

The main focus was to significantly reduce the spacing between the A320 family and B777/A330/A340. These two families represent more than 70% of the arrival traffic mix during the two peak hours.

These benefits are also expected to affect new aircraft types such as the A320 Neo, B737 Max family, B777/787, A350/330. Moreover, A380 separation reduction behind this giant was revised and included an extension of the Light Wake category.

RECAT-EU in action

Within Paris-CDG terminal control area, for the incoming flights at Paris-CDG and Paris-Le Bourget airports, six categories of aircraft and separation between leader/follower aircraft have been defined. Deployment of this innovative operational procedure was accompanied by a large, comprehensive air traffic controller training programme and stakeholders’ awareness information.

On 22 March 2016, RECAT-EU was implemented. In the near future, fine-tuned time-based separations on departure will also be implemented, supporting the full potential of RECAT-EU’s expected capacity benefits.

After two years in operation, there have been many benefits to the implementation of RECAT-EU:

  • Safety: RECAT-EU has led to increased flexibility in traffic separation delivery and the better integration of light aircraft and differences in tonnage.
  • Capacity: enhanced runway throughput means that Paris-CDG capacity at peak periods has increased by two to four aircraft movements per hour. Peak throughput was also maintained with unfavourable traffic mix in adverse situations.

"We are proud of this achievement that accompanies the increasing traffic at Paris-CDG airport. RECAT-EU is a real breakthrough in terms of safety, environment and capacity," says Marc Houalla, Paris-CDG airport managing director.

This major achievement for French ATM was highlighted by an award in the Environment Category during the World ATM Congress in Madrid in March 2018.