system failing/planned outages can also cause flow control or the shutting down of sectors. if you have a radar go down your standards increase and you just can't fit as many planes in the same airspace cause you protect more airspace for non-radar. i know someone is going to say "well do you got back ups for system failures?". haha we have a direct power line that feeds our building, back up diesel generator that can run for 3 days before refuelling, that’s backed up by a battery generator that can run for a day or something. with all the back ups to back ups, our building has lost power 3 times in the last about 4 years. on wed. some back hoe cut a fiber optics line somewhere between winnipeg and thunderbay. because of that and everyday outages i had to work with these outages. terminal freq was lost so had to run there airspace, one high freq lost, weather info not being updated for over 2 hours, singal source radar, one tacan out, survey work being done on a runway, ils approach notam'd, vor approach notam'd, 2 phone lines to airports were out, internet down and another radar unrealiable. but thats what makes the job fun.