 Aviation machinist's mate

Aviation Machinist's Mates (abbreviated as AD) are United States Navy aircraft engine mechanics that inspect, adjust, test, repair, and overhaul aircraft engines and propellers.More specifically, ADs install, maintain, and service various aircraft engine types as well as various accessories, gear boxes, related fuel systems, and lubrication systems; determine reasons for engine degradation using various test equipment; perform propeller repairs; handle and service aircraft ashore or aboard ship; and can also serve as aircrewman in various types of aircraft.