U.S. Air Force Airman 1st Class Joshuea Bryant-Thomas, 633rd Civil Engineer Squadron water and fuel systems maintenance technician, adjusts the opening speed on a back pressure control valve in the pump house at Langley Air Force Base, Va., Nov.6, 2015. The pump house distributes Jet-A fuel to be pumped underground to the flight line. (U.S. Air Force photo by Staff Sgt. John D. Strong II/Released)