Airman 1st Class Christopher Coon, 364th Training Squadron hydraulic systems apprentice course student, changes out an engine driven hydraulic pump on a C-130 Hercules. The engine drives the pump, providing hydraulic pressure to subsystems such as flight controls, steering, brakes and landing gear. Coon and his classmates are in block five of the eight block course. (U.S. Air Force phot by Senior Airman Robert L. McIlrath)