The Assault Amphibious Vehicle (AAV)—official designation AAVP-7A1 (formerly known as Landing Vehicle, Tracked, Personnel-7 abbr. LVTP-7)—is a fully tracked amphibious landing vehicle manufactured by U.S. Combat Systems (previously by United Defense, a former division of FMC Corporation). The AAV-P7/A1 is the current amphibious troop transport of the United States Marine Corps. It is used by U.S. Marine Corps Amphibious Assault Battalions to land the surface assault elements of the landing force and their equipment in a single lift from assault shipping during amphibious operations to inland objectives and to conduct mechanized operations and related combat support in subsequent mechanized operations ashore. It is also operated by other forces. Marines call them "amtracs", a shortening of their original designation, "amphibious tractor". In June 2018, the Marine Corps announced they had selected the BAE Systems/Iveco wheeled SuperAV for the Amphibious Combat Vehicle (ACV) program to supplement and ultimately replace the AAV. History Development The U.S. Marine Corps became interested in replacing the LVTP-5 due to its limited range, slow water speed and the difficulty of maintaining the aging platform. In 1964, the Marine Corps solicited proposals to replace meet its requirement. The Marine Corps selected a proposal by FMC. FMC delivered the first of 15 prototypes, designated LVTPX12, in October 1967. Marine Corps testing concluded in September 1969. In June 1970, the Marine Corps awarded FMC a $78.5 million contract for the production of 942 vehicles. The LVTP-7 was first introduced in 1972. In 1982, FMC was contracted to conduct the LVTP-7 Service Life Extension Program (SLEP), which converted the LVT-7 vehicles to the improved AAV-7A1 vehicle by adding an improved engine, transmission, and weapons system and improving the overall maintainability of the vehicle. The Cummins VT400 diesel engine replaced the GM 8V53T, and this was driven through FMC's HS-400-3A1 transmission. The hydraulic traverse and elevation of the weapon station was replaced by electric motors, which eliminated the danger from hydraulic fluid fires. The suspension and shock absorbers were strengthened as well. The fuel tank was made safer, and a fuel-burning smoke generator system was added. Eight smoke grenade launchers were also placed around the armament station. The headlight clusters were housed in a square recess instead of the earlier round type. The driver was provided with an improved instrument panel and a night vision device, and a new ventilation system was installed. These upgraded vehicles were originally called LVT-7A1, but the