U.S. Navy Sailors assigned to the 366th Training Squadron for training perform emergency repairs to a simulated water main in the Water and Fuel Systems Maintenance Apprentice course at Sheppard Air Force Base, Texas, June 24, 2015. Students in the course learn how to install, inspect, maintain, troubleshoot, modify and repair potable and waste water systems ensuring they comply with environmental and safety regulations. (U.S. Air Force photo/Danny Webb/Released)