Amphibious assault ship

An amphibious assault ship (AAS) is a type of amphibious warfare ship designed for spearheading amphibious incursions of marines into enemy territories during an armed conflict, via launching either naval landings or air assaults and also by providing shipborne close air support and logistics for landed friendly forces. Such a ship is typically the capital ship of a dedicated fleet known as the amphibious ready group or expeditionary strike group.

Amphibious assault ships evolved from aircraft carriers converted for specific use as helicopter carriers, which, as a result, are often mistaken for conventional fixed-wing aircraft carriers. Like the aircraft carriers they were developed from, some amphibious assault ships also support V/STOL fixed-wing aircraft, and some latest models (e.g. China's Type 076) have catapult systems for assisted takeoff of fixed-wing light aircraft such as UCAVs and have a secondary role as drone carriers. Most modern AAS designs also carry landing craft with most including a well deck, usually at the stern, to support large LCACs (hovercraft) and LCUs, which can insert both infantry and combat vehicles directly onto land.

The role of the amphibious assault ship is fundamentally different from that of a standard aircraft carrier: the aviation facilities of AASs have the primary role of hosting V/STOL aircraft (mainly helicopters and tiltrotors) for large-scale troop landing and some close air support, while conventional aircraft carriers are designed primarily for fast cyclic sorties of carrier-based combat aircraft (mostly fixed-wings) whose main roles are air superiority and airstrikes. Some AASs are capable of serving in the sea-control role, embarking more anti-submarine helicopters to clear the path for other friendly warships, while also operating as a safe seaborne base for large numbers of STOVL strike aircraft like the Harrier or the F-35B for combat air patrol and providing air support for an expeditionary unit ashore.

The largest fleet of amphibious assault ships is operated by the United States Navy, including the Wasp class dating back to 1989 and the very similar America-class ships which entered service in 2014. Just as an aircraft carrier leads a carrier strike group in the US Navy, an amphibious assault ship leads an expeditionary strike group. Amphibious assault ships are also operated by the Chinese People's Liberation Army Navy, the British Royal Navy, the French Navy, the Italian Navy, the Spanish Navy, the Royal Australian Navy, the Brazilian Navy, the Egyptian Navy, the Republic of Korea Navy (South Korea) and the Turkish Naval Forces.

The term amphibious assault ship is often used interchangeably with other ship classifications. The United States Navy hull classification currently categorizes full-length flight decked ("carrier-type") amphibious warfare ships into three classes, namely the landing platform helicopter (LPH), landing helicopter assault (LHA) and landing helicopter dock (LHD), all regarded as amphibious assault ships.