RECAT-EU Benefits Schiphol

Greater runway capacity thanks to shorter distances

Tailgating. An irritating and dangerous habit on the roads. This doesn’t happen in the air. Aircraft need a safe distance from one another. If the second aircraft is too close behind the first, it can be affected by wake turbulence. That’s why a minimum distance is prescribed between two aircraft. How does this work exactly? And how can we have aircraft land safely without adversely affecting efficiency?

Light, Medium, Heavy and Super Heavy 

Tailgating in the air is simply not done. Air traffic control ensures there is sufficient distance between two consecutive aircraft. The minimum distances are laid down in International Civil Aviation Organization (ICAO) legislation. Here, aircraft are classified in four weight categories: Light, Medium, Heavy and – since the advent of the Airbus A380 – Super Heavy. The minimum distance between landing aircraft is expressed in set distances: from three to eight nautical miles. These are safe distances, in fact more than safe. Yet at busy airfields they can also form a bottleneck for the runway throughput. So not that efficient really…

Can we refine these four categories?

At international level a great deal of research has already been conducted into concepts that could improve efficiency, without endangering safety. One option is to refine the aircraft categories. In other words: to create a more refined distinction between certain types of aircraft. The initial result of this in Europe is RECAT-EU, developed by Eurocontrol.

The NLR investigated this for us

The Netherlands Aerospace Centre (NLR) evaluated RECAT-EU on behalf of the European Aviation Safety Agency (EASA). This is because EASA would like to include RECAT-EU in ICAO legislation. It is encouraging countries to make use of it already. 

From four to six categories

In RECAT-EU the Heavy and Medium categories have been split roughly into two. This creates a total of six categories. This means that we can reduce the distance between e.g. Lower Heavy and Upper Medium aircraft from five to three nautical miles. If a Light aircraft is flying behind an Upper Heavy or Medium aircraft, we increase the distance. However, at Schiphol there are few Light aircraft in the air during peak times. This therefore has little effect on Schiphol capacity. 

Great improvement during peak times

What effect would RECAT have on the number of aircraft that can land at Schiphol? The NLR conducted a study into this. Gerben van Baren, Senior Consultant Air Transport Safety at the NLR, tells us more: “We focused on peak times in particular. That’s because creating extra capacity or reducing delays would be most helpful at these times. A relatively high number of Heavy aircraft land during the morning peak time. RECAT-EU would allow about one extra aircraft to land an hour. During the afternoon peak, which mainly involves a lot of Medium air traffic, this figure is slightly lower.”

Text image: Reduced separation between Heavy and Medium aircraft using RECAT-EU at Schiphol

RECAT-EU at Schiphol is not far off!

Gerben van Baren: “We can introduce the change from four to six categories using RECAT-EU relatively easily.” RECAT-EU is already operational at Paris Charles de Gaulle. And the US variant (RECAT-US) is used at about 10 airports. LVNL plans to introduce RECAT simultaneously with TBS (Time Based Separation). However, it is not yet known exactly when that will be.

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