Airmen deployed from the 171st Air Refueling Wing, Pennsylvania Air National Guard, check the ruddervator panels of a replacement boom for a KC-135 Stratotanker after attaching it to the plane in support of Operation Unified Protector at an undisclosed base in Western Europe on April 12, 2011. Assigned to the 313th Air Expeditionary Wing, the Airmen are supporting Operation Unified Protector, a NATO-led mission in Libya, to protect civilians and civilian-populated areas under threat of attack. The 313th AEW provides aerial refueling to U.S. and coalition aircraft with KC-135 Stratotankers and KC-10 Extenders. (U.S. Air Force Photo/Senior Airman Ethan Morgan)