Preflight inspections
Staff Sgt. Sean Durkin reviews a technical order prior to inspecting the engines of a C-17 Globemaster III April 12, 2011, at Spangdahlem Air Base, Germany. Sergeant Durkin is an aircraft hydraulics journeyman assigned to the726th Air Mobility Squadron. (U.S. Air Force photo/Senior Airman Nathanael Callon)