Related domains Air Traffic Management FAQs Airspace Usage requirements – DLS/CPDLC (controller-pilot data link communication)Airspace Usage requirementsRegulations PDF What is the DLS IR applicability? Answer The DLS IR is applicable to all IFR (Instrument flight rule) GAT (general air traffic) flights operating above FL 285 within airspace as identified in Annex I of the regulation. Last updated 11/06/2020 Was this helpful? Yes No