Naviair has placed its Frequentis PRISMA-based backup air traffic management system into live operation, securing continuity for Denmark’s Area Control Centre and major airports including Copenhagen, Billund, and Roskilde. The dissimilar secondary automation replaces the legacy Clear-The-Sky backup, delivering unlimited traffic handling during primary system failures or planned maintenance windows. Built on the open MOSAIX framework, PRISMA mimics the primary Human-Machine Interface to eliminate controller retraining while enabling future service integration. This deployment addresses ICAO guidance for manufacturer-diverse backups, mitigating shared software vulnerabilities and preventing ATC Zero scenarios. Naviair’s COO Morten Fruensgaard confirms the system meets highest operational standards, ensuring uninterrupted safety-critical services across the national airspace.