U.S. Air Force Technical Sgt. Severin Koerner, a crew chief with the 144th Aircraft Maintenance Squadron, inspects the exhaust of an F-16 Fighting Falcon during a pre-flight inspection while at Sentry Aloha on Sept. 8, 2009. Sentry Aloha is an exercise that brings disimilar combat assets to Hickam to train with the Hawaii National Guard. (U.S. Air Force photo by Staff Sgt. Charles P. Vaughn) (Released)