Anything man made is subject to break down or fail...I know of events in the USA that lost entire flight data entry systems in Memphis ARTCC, Atlanta ARTCC, and loss of Primary and Primary Backup Radar systems being lost for at least 30 minutes at Cleveland ARTCC and Indianapolis ARTCC.....so it comes with the territory....sad to say with todays traffic volumes Non-Radar procedures help a small percentage of the time.......
