The Federal Aviation Administration threw in the towel Tuesday and abandoned its plan to shift part of the Boise Airport air traffic control system to Salt Lake City. The agency began informing members of the Idaho Congressional delegation Tuesday that it was scrapping its controversial plan to move the Terminal Radar Approach Control system — or TRACON — now housed at the airport. The plan had been under fire from the the National Association of of Air Traffic Controllers Association, Idaho delegation members, Boise officials and the local aviation community since it was proposed in 2006.