The Douglas A-4 Skyhawk was designed to replace the piston-engined AD Skyraider in the close air support and interdiction role. It was capable of carrying both conventional and nuclear weapons. The prototype flew on 22 June, 1954. The first production model, the A-4A (165 built), entered service in 1956. The A-4B (542 built) entered service in 1957. The A-4C (638 built), entered service in 1960, and introduced a new radar unit which provided limited night and bad weather capability. The A-4E (498 built), was equipped with a more powerful engine and other improvements and entered service in late 1962. The A-4F was a modified version of the “E” model and included an upgraded engine, nose wheel steering, wing spoilers, a zero-zero ejection seat, and an upper avionics pod which gave the aircraft its characteristic “humpback” shape. The A-4G entered service with the Royal Australian Navy in 1967. It was armed with Sidewinder missiles and flew from the carrier Melbourne.