contrails

Hi all -

Someone at my company was jumpseating on FedEx and he said the crew told him he was on a flight that would do what was known as sweeps. Staying in the air for about an extra hour in case a plane broke down somewhere at an outstation.

I'd heard a few years ago that FedEx supposedly flew an empty plane across the middle of the country in circles for this reason and that seemed like BS because that's a lot of money for hauling zero cargo. This, however, came right from the crew's mouth and they were on a flight with cargo, just staying up for a little longer. So I suppose it is true after all.

I'm just curious as to how that works. Does each hub (MEM, IND, EWR? OAK?) get a flight like this, or is it just for the area near MEM? And how is it determined when the sweeper flight can land?

Thanks...seems like a thing that is unique to just FedEx.