Staff Sgt. Bryce Woodall, and Airman 1st Class Jeremiah Palmer, 28th Aircraft Maintenance Squadron hydraulic technicians, open a panel on a B-1 bomber to install a pre-cooler blower at Ellsworth Air Force Base, S.D., May 8, 2013. Aircraft hydraulic system specialists have knowledge of hydraulic, pneumatic, electrical and mechanical principles applicable to aircraft and support equipment and hydraulic systems. (U.S. Air Force photo by Airman 1st Class Zachary Hada/Released)