South Korea is seeking to buy about twenty retired American S-3 anti-submarine warfare (ASW) aircraft to augment South Korean ability to find and destroy North Korean submarines. The United States retired the last of its S-3s in 2009 but put dozens in storage, just in case. Before putting these aircraft in storage the navy took advantage of new, lightweight, search radars and targeting pods and in 2006 began equipping S-3 aircraft with Lantirn targeting pods. This was in an effort to extend the life of the S-3s, as reconnaissance aircraft. That did not prevent the retirement decision.
The S-3 was originally designed as an anti-submarine aircraft, and served in that capacity from its introduction in the mid-1970s, to the late 1990s. The end of the Cold War ended most of the submarine threat so after 1999 the S-3 has served as a patrol aircraft and aerial tanker. It was hoped that a reequipped S-3, with the long endurance (ten hours per sortie), day/night video capability of the Lantirn, and lightweight search radar, would make it a much more effective maritime patrol aircraft. The Lantirn pod costs two million dollars, and is hung off a hard point like a bomb or fuel tank. Despite this effort some 90 late model S-3s, about half the 188 manufactured, are in storage and can be brought back to service in a few months. South Korea would add some of its own electronics and begin using the S-3s for ASW work.
The 23 ton S-3 is a twin-jet ASW aircraft designed to operate from aircraft carriers. It carries a crew of four (two pilots and two equipment operators) and up to 2.2 tons of weapons (bombs, mines, depth charges, ant-submarine torpedoes). Cruise speed is 650 kilometers an hour and stall (slowest) speed is 180 kilometers an hour. Also carried are sixty sonobuoys plus extensive electronics (search radar, night vision camera and magnetic anomaly detector).