A U.S. Air Force non-destructive inspection apprentice assigned to the 1st Maintenance Squadron pours slop oil into a boat before analyzing the oil at Langley Air Force Base, Va., Sept 22, 2015. After the technician pours the oil into the boat, the boat is inserted into an optical emission spectrometer that will burn the oil to measure the intensity of the light it emits, alluding to the type of particles in the oil. (U.S. Air Force photo by Senior Airman Aubrey White/Released)