Lockheed S-3 Viking

Summary

Description

The S-3 was developed in response to the VSX program conducted by the U.S. Navy (USN) to procure a successor anti-submarine warfare (ASW) aircraft to the Grumman S-2 Tracker. It was designed, with assistance from Ling-Temco-Vought (LTV), to be a carrier-based, subsonic, all-weather, long-range, multi-mission aircraft. During August 1968, a team led by Lockheed, as well as a rival team comprising Convair and Grumman, were requested to further develop their proposals to meet this requirement. LTV assumed responsibility for the design of various elements of the airframe, such as the folding wings and tail, the engine nacelles, and the landing gear, some of which had been derived from the earlier LTV A-7 Corsair II and Vought F-8 Crusader. Sperry Univac Federal Systems was assigned the task of developing the aircraft's onboard computers which integrated input from sensors and sonobuoys. On 4 August 1969, Lockheed's design was selected as the winner of the VSX contest; an order for eight prototypes, designated YS-3A, was promptly received by the company. On 21 January 1972, the first prototype performed its maiden flight in the hands of military test pilot John Christiansen. Two years later, the S-3 entered operational service with the U.S. Navy. During the type's production run, which ran from 1974 to 1978, a total of 186 S-3As were constructed.

The Lockheed S-3 Viking is a conventional monoplane characterized by a cantilever shoulder wing, very slightly swept with a leading edge angle of 15° and an almost straight trailing edge. Its twin GE TF-34 high-bypass turbofan engines are mounted in nacelles under the wings; their fuel efficiency provides the Viking with long range and endurance, while also maintaining relatively docile engine-out characteristics. It can seat four crew members, with pilot and copilot/tactical coordinator (COTAC) in the front of the cockpit, and the tactical coordinator (TACCO) and sensor operator (SENSO) in the back. Entry is via a hatch/ladder folding down out of the lower starboard side of the fuselage behind the cockpit, in between the rear and front seats on the starboard side. The wing is fitted with leading edge and Fowler flaps, and spoilers are fitted to both the upper and the lower surfaces of the wings. All control surfaces are actuated by dual hydraulically boosted irreversible systems; in the event of dual hydraulic failures, an Emergency Flight Control System (EFCS) permits manual control, with greatly increased stick forces and reduced control authority. The S-3 was equipped with an auxiliary power unit (APU) capable of unassisted starts. The APU itself was started from a hydraulic accumulator by pulling a handle in the cockpit. All crew members sit on forward-facing, upward-firing Douglas Escapac zero-zero ejection seats.

The S-3 Viking accommodates up to 4,900 pounds of ordnance on its four internal bomb bay stations and two external hardpoints. It is capable of carrying a mix of general-purpose bombs, including ten 500-pound Mark 82s, two 1,000-pound Mark 83s, or two 2,000-pound Mark 84s, as well as six CBU-100 cluster bombs. For anti-submarine warfare, the aircraft can deploy two Mark 50 or four Mark 46 torpedoes, in addition to six mines or depth charges. Furthermore, the S-3 is equipped to carry two B57 nuclear bombs, along with air-to-surface missiles such as two AGM-65E/F Mavericks, two AGM-84D Harpoons, or one AGM-84H/K SLAM-ER missile. The underwing hardpoints can also be configured to carry unguided rocket pods or 300-gallon external fuel tanks. Finally, it carries fifty-nine sonobuoys, and also features an ALE-39 countermeasure system capable of carrying up to 90 rounds of chaff, flares, and expendable jammers.

The S-3A officially became operational in February 1974, with Air Antisubmarine Squadron FORTY-ONE (VS-41) at NAS North Island, California. Early Viking operations faced challenges, as the sophisticated mission systems heavily relied on a mission computer prone to "dumping" during catapult launches, requiring restarts and software reloads. Insufficient spare parts initially hampered mission readiness, but performance improved with adequate provisioning, establishing the S-3 as a valuable ASW asset and surface-surveillance platform. Starting in 1987, most S-3As underwent upgrades to the S-3B standard, gaining new sensors, avionics, and the ability to launch the AGM-84 Harpoon anti-ship missile. The S-3B also acquired the ability to carry "buddy stores" for aerial refueling. Following the Cold War, the aircraft's mission shifted to sea surface search, attack, targeting, and refueling, and Viking squadrons were redesignated from "Air Antisubmarine Warfare Squadrons" to "Sea Control Squadrons". The S-3B saw service during the 1991 Gulf War, performing attack, tanker, and ELINT duties, as well as in the Yugoslav wars in the 1990s and Operation Enduring Freedom in the 2000s.

Main Variants:

• S-3A: The first production version, it served primarily in anti-submarine warfare (ASW) and maritime surveillance roles.

• S-3B: Featuring upgraded avionics, including the AN/APS-137 inverse synthetic aperture radar and the capability to launch the AGM-84 Harpoon missile, this variant shifted towards anti-surface warfare.

• ES-3A Shadow: Designed for carrier-based electronic intelligence (ELINT) duties, it carried an extensive suite of electronic sensors and communications gear, replacing the S-3's submarine detection and armament.

• KS-3A: A proposed dedicated air tanker, only one was converted from a YS-3A prototype and later reconfigured to a US-3A.

• US-3A: Modified for carrier onboard delivery, this variant provided a capacity for six passengers or 4,680 pounds (2,120 kg) of cargo, supporting logistics operations at sea.

Technical specifications

Current operating countries

No country is operating the S-3 Viking in 2025.

All operators

United States

Armament

Bombs payload:

• Thermonuclear B57 Mod 1
• Cluster Mk 20 Mod 0 Rockeye
• Low-Drag Mk 82
• Low-Drag Mk 83
• Low-Drag Mk 84

Photo of S-3 Viking

3-view profile