An Airman from the 493rd Expeditionary Fighter Squadron aircraft maintenance unit signals to his team that an F-15C systems check is complete at Siauliai Air Base, Lithuania, Aug. 31, 2017. The 439rd EFS AMU ensures that all aircraft are ready at a moments notice to meet the needs of the NATO Baltic Air Police mission. (U.S. Air Force photo/ Tech. Sgt. Matthew Plew)