Tactical Air Navigation System
Master Sgt. Michael Thomsen, 241st Air Traffic Control Squadron, examines the innards of a Tactical Air Navigation System (TACAN) at Rosecrans Air National Guard Base, St. Joseph, Mo., April 13, 2012. The newly acquired TACAN acts as a navigation system for pilots. (U.S. Air Force photo by Staff Sgt. Michael Crane/Missouri Air National Guard)