U.S. Air Force Senior Airman Zachery Gray, right, assigned to the 455th Expeditionary Aircraft Maintenance Squadron, receives a certificate of appreciation from Polish air force Col. Andrzej Kusneierek, left, during a ceremony at Bagram Airfield, Afghanistan, Jan. 3, 2013. Gray was part of a team that replaced a propeller on a Polish C-130 Hercules aircraft.