Airman 1st Class Steven McCray, 13th Aircraft Maintenance Unit B-2 Spirit crew chief, communicates with pilots during a pre-flight inspection at Whiteman Air Force Base, Mo., April 5, 2013. Crew chiefs from the 509th Aircraft Maintenance Squadron are responsible for inspecting, troubleshooting and maintaining Whiteman's B-2 Spirits, ensuring the aircraft are combat- ready to support global strike operations and nuclear deterrence. (U.S. Air Force photo by Staff Sgt. Nick Wilson)