AFOD supports the retrieval of AIXM 5.1 features located fully or partially in a referenced airspace identified by its gml:identifier (UUID). The following spatial operators are supported: Beyond, Contains, Crosses, Disjoint, DWithin, Equals, Intersects, Overlaps, Touches and Within.
Reference
SDD XML Primer - Section 2.3.6.1.6
https://ost.eurocontrol.int/sites/EADSSI/eadssi/SDD-AIXM%205.1/Transition%20to%20SDD/Reference%20Documents/SDD%20XML%20Primer.zip