Fuel keeps aircraft flying
Senior Airman Daniel Shelly, 374th Logistics Readiness Squadron fuels management flight fuels laboratory supervisor, prepares a sample pad for a water test on a refueling unit at Yokota Air Base, Japan, Oct. 1, 2015. This test is performed monthly to ensure only good, clean and water-free fuel is issued to aircraft. (U.S. Air Force photo by Senior Airman David Owsianka/Released)