Airman 1st Class Zachery Brackeen, 28th Aircraft Maintenance Squadron crew chief, services the Cn2 hydraulic system on the B-1B Lancer engine at Ellsworth Air Force Base, S.D., Jan. 21. The Cn2 system runs all of the hydraulics on the aircraft and is maintained and refilled as needed to ensure the proper flow of fluids. (U.S. Air Force photo/Senior Airman Anthony Sanchelli)