Immediately following the outage, it was business as usual at Cleveland Air Route Traffic Control Center in Oberlin.

"We're open," said an unnamed FAA source. "We can operate in an electrical power vacuum, but the airlines can't."

Why? When the power outage occurred, instantaneous battery backup provided power for a few minutes until diesel generators took over for all the center's electrical components. The generators can provide power indefinitely, as long as there is access to diesel fuel.