Staff Sgt. Mario Beltran, 316th Security Forces Squadron patrolman, scans for any threats while the motorcade for Chilean President Sebastia Pinera leaves the flight line at Joint Base Andrews, Md., April 11, 2010, on its way to the Nuclear Security Summit hosted by President Barack Obama in Washington, D.C., this Monday and Tuesday. The 316th Wing is leading operations to provide safe, effective, and efficient arrival and departure services for the invited guests transiting Andrews. (U.S. Air Force photo by Airman 1st Class Perry Aston) (Released)