I am extremely disappointed that many valued and hard-working colleagues may have to leave the organisation.
It's a decision the board and I have not taken lightly; it's one we have tried to avoid and it is the first time in almost 30 years of business that we have had to take such action.
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Guillier conceded a "severe defeat" defeat to his supporters as the result came in.
The outage struck Hartfield-Jackson Atlanta International Airport at around 1pm local time, stopping all outgoing flights.
It will be a chilly day for many parts with the highest temperatures, about 10 Celsius (50F) in the far northwest.