an ATS route that is only available for flight planning and use under specified conditions.
A Conditional Route may have more than one category, and those categories may change at specified times:
a) Category One - Permanently Plannable CDR:
CDR1 routes are available for flight planning during times published in the relevant national Aeronautical Information Publication (AIP).
b) Category Two - Non-Permanently Plannable CDR:
CDR2 routes may be available for flight planning. Flights may only be planned on a CDR2 in accordance with conditions published daily in the CRAM, and
c) Category Three - Not Plannable CDR:
CDR3 routes are not available for flight planning; however, ATC Units may issue tactical clearances on such route segments.
EUROCONTROL (2010) Guidelines: The ASM Handbook, Airspace Management Handbook for Application of the Concept of the Flexible Use of Airspace, Ed. 3.0, Reference nr: EUROCONTROL-GUID-140