Staff Sgt. David Perez explains procedures on how to replace a downed driver in a High-Mobility Multipurpose Wheeled Vehicle during tactical vehicle training at Joint Base Charleston, S.C., April 24, 2012. The monthly training is given to members of the 628th Security Forces Squadron to familiarize them with operating tactical vehicles and how to perform security checks while in a convoy. Perez is a 628th SFS trainer. (U.S. Air Force photo/ Staff Sgt. Nicole Mickle)