European Organisation for the Safety of Air Navigation

Following the successful implementation, in December 2013, of a Variable Division Flight Level (vDFL) in the eastern part of the airspace managed by the Maastricht Upper Area Control Centre (MUAC), the concept has been further deployed to the western part of the airspace, covering Dutch and north-west German airspace, the so-called DECO sectors, as of 11 December 2014.

The vDFL concept allows for a more flexible and dynamic distribution of traffic between upper and lower sectors (from 24,500 feet to UNL) with a view to increasing efficiency. vDFL is the first step towards the introduction of the dynamic sectorisation concept for Single European Sky ATM Research (SESAR).

In the DECO sectors, the division flight level between the upper and lower sectors was fixed at 34,500 feet. However, since traffic distribution is not constant throughout the day it is now possible, with the introduction of vDFL, to vary the division flight level between sectors, thereby allowing the most optimum sector configuration/sector volumes to be chosen to meet traffic demand. Better distribution of traffic between sectors results in increased operational staff efficiency, an increased capacity for future traffic increases without the requirement to apply traffic management measures, and improved environmental efficiencies since less traffic is restricted to a level below the high sectors.

The continued development of this philosophy will see an expansion of the concept to the densest and most complex areas of the MUAC airspace – above Belgium and Luxembourg – increasing ATM performance still further.  

The advanced ATC system in place at MUAC is capable of supporting this instant restructuring of sectors across multiple division flight levels. Thanks to the dynamic frequency management infrastructure, level bands of sectors and airspace blocks can be changed instantly within the system.