RAD: Traffic signs in the air
To steer traffic flows one central element is the so-called Route Available Document (RAD) which is in fact a set of “traffic signs in the air” compiled in an Excel file by Eurocontrol Network Manager. The measures described in this document are local route instructions such as the height or the direction of flights. The measures are binding as they are endorsed and published by States. The frequency of RAD changes is based on the Aeronautical Information Regulation and Control (AIRAC) cycle which enables changes to be introduced on a 4-weeks basis and follows a longer pre-publication notice period to alert airspace users and their respective external suppliers.
The number of RAD measures is highly dependent on the congestion and complexity of an airspace. In the same way road traffic signs increase as you get closer to a busy city, airspace rules also become more frequent. RAD measures also increase when new operational concepts such as Free Route are introduced.FABEC used the period of low traffic during the pandemic to remove hundreds of RAD measures to provide more flexibility for airspace users. Coincidently, the introduction of Free Route led to the introduction of several new RAD measures.