Aviation ordnance refers to the weapons, weaponry systems, and explosives that armed aircraft use. U.S. military branches, primarily the Navy, Marines, and Air Force, have specially trained aviation ordnanceman to handle, install, and maintain these systems. These positions are often someone who has enlisted in the armed forces, but some branches also hire civilians for this type of work. Civilians involved in this field may work for the military or a private company who is contracted with the armed forces to supply these kinds of weapons. Their job duties may include inspecting the weapons for problems and installing or repairing the systems as necessary. Aviation ordnance workers also ensure the safe transportation and storage of arms and the disposal of damaged or faulty weapons.