U.S. Air Force Lt. Gen. Sid Clarke, left, Commander of Continental United States North American Aerospace Defense Command Region and First Air Force (Air Forces Northern), presents a certificate of retirement to Col. Randy Spear during a retirement ceremony held here Nov. 20, 2012. Colonel Spear served as the commander of the 601st AOC for nearly three and half years. The 601st AOC is responsible for detecting, deterring, defending and if necessary, defeating any aviation threat to the citizens of the United States and to U.S. critical infrastructure. (U.S. Air Force photo by Lisa Norman/Released)