U.S. Air Force Tech Sgt. William Bandy, 192nd Fighter Wing aerospace ground equipment technician, ensures a valve is closed on an electric hydraulic test stand unit at Langley Air Force Base, Va., Sept. 10, 2014. Aerospace ground equipment Airmen serve as a key element to the aircraft mission, ensuring proper maintenance can be performed on each aircraft. The Airmen are also certified in maintaining heating, ventilation and air conditioning systems. (U.S. Air Force photo by Senior Airman Connor Estes/Released)