Peek-a-boo
Tech. Sgt. Joseph Gonzales, 92nd Maintenance Squadron, Aircraft Fuel Systems section chief, peers into the section of a fuel tank training module, a section of a former KC-135 Stratotanker's wing, during a training session at Fairchild Air Force Base, Washington, Nov. 21, 2017. A KC-135 possesses eight, wing-borne fuel tanks and 16 fuel cells in the fuselage of the aircraft. (U.S. Air Force photo/Senior Airman Ryan Lackey)