Col. Brian Newberry, 92nd Air Refueling Wing commander and Airman 1st Class Collin Braun, 92nd Aircraft Maintenance Squadron electrical/environmental systems technician, perform a malfunction analysis of the auxiliary power unit starter system at Fairchild Air Force Base, Wash., on June 12, 2013. APUs are critical in supplying power to aircraft engines. (U.S. Air Force Photo by Staff Sgt. Jordan Pollock/Released)