The Lockheed S-3 Viking is a United States Navy jet aircraft used to hunt and destroy enemy submarines and provide surveillance of surface shipping. The S-3B version can be fitted with buddy stores, external fuel tanks that refuel other aircraft, to act as an airborne tanker. The ES-3A electronic reconnaissance version was fitted for electronic warfare and reconnaissance. Because of the high-pitched sound of the aircraft's engines, it is nicknamed the "Hoover" (after the vacuum cleaner).
The S-3A Viking replaced the piston-engined Grumman S-2 Tracker and entered fleet service in 1974. The S-3 is a carrier-based, subsonic, all-weather, long-range, multi-mission aircraft. It operates primarily with carrier battle groups in anti-submarine warfare roles. It carries automated weapon systems and is capable of extended missions with in-flight refueling.The last production S-3A was delivered in August 1978. The inventory includes S-3As and S-3Bs. Sixteen S-3As were converted to ES-3 Shadows for carrier-based electronic reconnaissance (ELINT) duties. A few units were also converted for utility and limited cargo duty, known as the US-3B, all of which were retired by 1998. Plans were also made to develop the KS-3A version out of the basic airframe, a carrier-based tanker aircraft to replace the retired KA-6 but these were ultimately canceled.
On May 1, 2003, US President George W. Bush rode in the co-pilot seat of a Viking that landed on the aircraft carrier USS Abraham Lincoln, where he delivered his "Mission Accomplished" speech announcing the end of major combat in the 2003 invasion of Iraq. That Navy flight is the only one to use the call sign "Navy One". Since the submarine threat has been perceived as reduced Vikings have had their antisubmarine warfare equipment removed and are now used primarily for sea and ground attack, sea surface search, over the horizon targeting, and aircraft refueling. As a result, crews are now usually limited to two people, but three people crews are not unusual with certain missions. Navy plans called for the retirement of all Vikings by 2009.