The Memphis Commercial Appeal newspaper is reporting that "...federal regulators have tweaked a key aviation standard to improve the flow of cargo jets in and out of FedEx's world hub at Memphis International Airport."
The report continues by saying that the new standards have been in place at Memphis since last Nov. 1, and will be expanded to other airports with concentrations of heavy, wide-body aircraft, including San Francisco, Louisville and Atlanta, over the next couple years.
The report says that minimum spacing between departing aircraft was reduced to 2.5-3 miles, from 4 miles for most planes. It also mentioned that spacing was increased for some smaller planes for wake turbulence separation standards. Arriving aircraft were not addressed.
My question is: How much (to what degree) does this reduce safety?