Army Staff Sgt. Kevan Katkus, left, and Sgt. Bradley McKenzie prepare their UH-60 Black Hawk helicopter to conduct flight operations on Joint Base Elmendorf-Richardson, Alaska, Oct. 21, 2015. Katkus and McKenzie are crew chiefs assigned to the Alaska Army National Guard's 1st Battalion, 207th Aviation Regiment. U.S. Air Force photo by Alejandro Pena