FORT HUACHUCA, Arizona -- An RQ-7BV2 Shadow unmanned aircraft system (UAS) conducting training flights within Fort Huachuca's R2303 restricted military airspace experienced an engine failure at approximately 2:40 p.m. Tuesday and deployed its emergency parachute at approximately 2:48 p.m. before crashing in a rural area of Santa Cruz County.Personnel from the 2-13th Aviation Regiment, assisted by the Fort's Directorate of Emergency Services along with Cochise County and Santa Cruz County Sheriff's Departments are assisting in recovery efforts. At this time, details about the current condition of the aircraft are unknown.The 2-13th Aviation Regiment operates the largest Unmanned Aircraft Systems training center in the world with over 125,000 square feet of training space, four hangars and three runways at Fort Huachuca, Arizona. Each year, the battalion trains approximately 2,000 Soldiers, Marines and foreign military students.