A little Professional Development… when the blackout happen in Atlanta airport, how was the message relayed to the other pilots; especially those on final or in the pattern being vectored. It was my understanding that the entire Center went offline. I guess the same for when the St Louis Center fire occurred in 2015.
The message was probably relayed by the lack of voice traffic, which would prompt pilots to check the frequency, then check other sector frequencies and then move onto adjacent facility frequencies. For example, if I was unable to raise Atlanta Center, I would then try the nearest facility, such as Jacksonville Center or Atlanta Approach Control. At some point, the airline dispatchers probably also notified their aircraft via ACARS, which is essentially text messaging for airplanes.
Also know that pilots have “Lost Comm” procedures for every phase of flight.