Euroopa Tsiviillennunduse Konverentsi (ECAC) piirkonnas kohaldatav õhuruumi korraldamise kontseptsioon, nagu see on määratletud Eurocontroli avaldatud käsiraamatus “Airspace Management Handbook for the Application of the Concept of the Flexible Use of Airspace”, an airspace management concept applied in the European Civil Aviation Conference area on the basis of the ‘Airspace management handbook for the application of the concept of the flexible use of airspace’ issued by Eurocontrol