"Air traffic controllers in the Dallas-Fort Worth area routinely covered up errors and their supervisors failed to investigate cases that included airplanes flying too close to each other, federal officials said. The incidents date back seven years at D-FW Terminal Radar Approach Control, which oversees air traffic at all of the area's airports, including Dallas-Fort Worth International Airport."
http://news.yahoo.com/news?tmpl=stor...nvestigation_2