Airman 1st Class Chun Liu, 28th Maintenance Squadron aerospace ground equipment technician, seals an oil cart lid during scheduled maintenance at Ellsworth Air Force Base, S.D., April 18, 2012. AGE technicians service, inspect, troubleshoot, repair and perform preventive maintenance on engine-driven generator sets, air conditioners, hydraulic test stands, air compressors, bomb lifts, heaters and other support equipment. (U.S. Air Force photo by Airman 1st Class Alystria Maurer/Released)