U.S. Air Force Staff Sgt. Joseph Rivera, right, with the 571st Contingency Response Group, fist-bumps a Rwandan soldier as they trade vehicles at Bangui M'Poko International Airport in the Central African Republic Jan. 19, 2014. U.S. forces were dispatched to provide airlift assistance to multinational troops in support of an African Union effort to quell violence in the Central African Republic.