Development

Development
Two U.S. Marine Corps Assault Amphibian Vehicles emerge from the surf onto the sand of Freshwater Beach, Australia
U.S. Marines landing from an Assault Amphibian Vehicle in Djbouti

The LVTP-7 was first introduced in 1972 as a replacement for the LVTP-5. In 1982, FMC was contracted to conduct the LVTP-7 Service Life Extension Program, 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 Marine Corps renamed the LVTP-7A1 to AAV-7A1 in 1984.

Another improvement was added in the form of a Cadillac Gage weapon station or Up-Gunned Weapon Station (UGWS) which was armed with both a .50 cal (12.7 mm) M2HB machine gun and a Mk-19 40 mm grenade launcher.

Enhanced Applique Armor Kits (EAAK) were developed for the AAV-7A1 in 1989 and fitted by 1993, and the added weight of the new armor necessitated the addition of a bow plane kit when operating afloat.

The Assault Amphibian Vehicle Reliability, Availability, Maintainability/Rebuild to Standard (AAV RAM/RS) Program has provided for a replacement of both the engine and suspension with US Army M2 Bradley Fighting Vehicle (BFV) components modified for the AAV. The ground clearance has returned to 16 inches and the horsepower to ton ratio has changed from 13 to 1 back to 17 to 1. The AAV RAM/RS rebuild encompassed all AAV systems and components in order to return the AAV back to the original vehicle’s performance specifications and ensure acceptable Fleet Marine Force (FMF) AAV readiness ratings until the EFV is operational. Introduction of the BFV components and the rebuild to standard effort is expected to reduce maintenance costs for the remaining life of the AAV through the year 2013. Though due to the cancellation of the EFV the AAV will remain in service much longer.