The Lockheed S-3 Viking is a 4-crew, twin-engine turbofan-powered jet aircraft that was used by the U.S. Navy (USN) primarily for anti-submarine warfare. In the late 1990s, the S-3B's mission focus shifted to surface warfare and aerial refueling. The Viking also provided electronic warfare and surface surveillance capabilities to a carrier battle group. A carrier-based, subsonic, all-weather, long-range, multi-mission aircraft, it carried automated weapon systems and was capable of extended missions with in-flight refueling. Because of its characteristic sound, it was nicknamed the "War Hoover" after the vacuum cleaner brand.
The S-3 was phased out from front-line fleet service aboard aircraft carriers in January 2009, with its missions taken over by aircraft like the P-3C Orion, P-8 Poseidon, Sikorsky SH-60 Seahawk, and Boeing F/A-18E/F Super Hornet. Several aircraft were flown by Air Test and Evaluation Squadron Thirty (VX-30) at Naval Base Ventura County / NAS Point Mugu, California, for range clearance and surveillance operations on the NAVAIR Point Mugu Range until 2016 and one S-3 was operated by the National Aeronautics and Space Administration (NASA) at the NASA Glenn Research Center until 2021.
S-3 escape system testing
In the mid-1960s, the USN developed the VSX (Heavier-than-air, Anti-submarine, Experimental) requirement for a replacement for the piston-engined Grumman S-2 Tracker as an anti-submarine aircraft to fly off aircraft carriers. In August 1968, a team led by Lockheed and a Convair/Grumman team were asked to further develop their proposals to meet this requirement. Lockheed recognised that it had little experience in designing carrier based aircraft, so Ling-Temco-Vought (LTV) was brought into the team, being responsible for the folding wings and tail, the engine nacelles, and the landing gear, which was derived from LTV A-7 Corsair II (nose) and Vought F-8 Crusader (main). 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 contest and 8 prototypes, designated YS-3A were ordered. The first prototype was flown on 21 January 1972 by military test pilot John Christiansen, and the S-3 entered service in 1974. During the production run from 1974 to 1978, a total of 186 S-3As were built. The majority of the surviving S-3As were later upgraded to the S-3B variant, with 16 aircraft converted into ES-3A Shadow electronic intelligence (ELINT) collection aircraft.
The S-3 is a conventional monoplane with a cantilever shoulder wing, very slightly swept with a leading edge angle of 15° and an almost straight trailing edge. Its 2 GE TF-34 high-bypass turbofan engines mounted in nacelles under the wings provide excellent fuel efficiency, giving the Viking the required long range and endurance, while maintaining docile engine-out characteristics.
S-3A with extended MAD-sensor
The aircraft can seat 4 crew members (3 officers and 1 enlisted) 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. When the aircraft's anti-submarine warfare (ASW) role ended in the late 1990s, the enlisted SENSOs were removed from the crew. In tanker crew configuration, the S-3B typically flew with a pilot and co-pilot/COTAC. The wing is fitted with leading edge and Fowler flaps. 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.
Unlike many tactical jets which required ground service equipment, the S-3 was equipped with an auxiliary power unit (APU) and capable of unassisted starts. The aircraft's original APU could provide only minimal electric power and pressurized air for both aircraft cooling and for the engines' pneumatic starters. A newer, more powerful APU could provide full electrical service to the aircraft. The APU itself was started from a hydraulic accumulator by pulling a handle in the cockpit. The APU accumulator was fed from the primary hydraulic system, but could also be pumped up manually (with much effort) from the cockpit.
All crew members sit on forward-facing, upward-firing Douglas Escapac zero-zero ejection seats. In "group eject" mode, initiating ejection from either of the front seat ejects the entire crew in sequence, with the back seats ejecting 0.5 seconds before the front in order to provide safe separation (this was to prevent the pilots, who were more aware of what was happening outside the aircraft from ejecting without the rest of the crew, or being forced to delay ejection to order the crew to eject in an emergency; ejection from either rear seat would not eject the pilots, who had to initiate their own ejections, to prevent loss of the aircraft if a rear crewmember ejected prematurely. If a pilot ejected prematurely, the plane was lost anyway, and automatic ejection prevented the crew from crashing with a pilot-less aircraft before they were aware of what had happened). The rear seats are capable of self ejection and the ejection sequence includes a pyrotechnic charge that stows the rear keyboard trays out of the occupants' way immediately before ejection. Safe ejection requires the seats to be weighted in pairs and when flying with a single crewman in the back the unoccupied seat is fitted with ballast.
At the time it entered the fleet, the S-3 introduced an unprecedented level of systems integration. Previous ASW aircraft like the Lockheed P-3 Orion and S-3's predecessor, the Grumman S-2 Tracker, featured separate instrumentation and controls for each sensor system. Sensor operators often monitored paper traces, using mechanical calipers to make precise measurements and annotating data by writing on the scrolling paper. Beginning with the S-3, all sensor systems were integrated through a single General Purpose Digital Computer (GPDC). Each crew station had its own display, the co-pilot/COTAC, TACCO and SENSO displays were Multi-Purpose Displays (MPD) capable of displaying data from any of a number of systems. This new level of integration allowed the crew to consult with each other by examining the same data at multiple stations simultaneously, to manage workload by assigning responsibility for a given sensor from one station to another and to easily combine clues from each sensor to classify faint targets. Because of this, the 4-crew S-3 was considered roughly equivalent in capability to the much larger P-3 with a crew of 12.
The aircraft has two underwing hardpoints that can be used to carry fuel tanks, general purpose and cluster bombs, missiles, rockets, and storage pods. It also has four internal bomb bay stations that can be used to carry general-purpose bombs, aerial torpedoes, and special stores (B57 and B61 nuclear weapons). Fifty-nine sonobuoys are carried, as well as a dedicated Search and Rescue (SAR) chute. The S-3 is fitted with the ALE-39 countermeasure system and can carry up to 90 rounds of chaff, flares, and expendable jammers (or a combination of all) in three dispensers. A retractable magnetic anomaly detector (MAD) Boom is fitted in the tail.
In the late 1990s, the S-3B's role was changed from anti-submarine warfare (ASW) to anti-surface warfare (ASuW). At that time, the MAD Boom was removed, along with several hundred pounds of submarine detection electronics. With no remaining sonobuoy processing capability, most of the sonobuoy chutes were faired over with a blanking plate.
On 20 February 1974, the S-3A officially became operational with the Air Antisubmarine Squadron FORTY-ONE (VS-41), the "Shamrocks," at NAS North Island, California, which served as the initial S-3 Fleet Replacement Squadron (FRS) for both the Atlantic and Pacific Fleets until a separate Atlantic Fleet FRS, VS-27, was established in the 1980s. The first operational cruise of the S-3A took place in 1975 with the VS-21 "Fighting Redtails" aboard USS John F. Kennedy.
Starting in 1987, some S-3As were upgraded to S-3B standard with the addition of a number of new sensors, avionics, and weapons systems, including the capability to launch the AGM-84 Harpoon anti-ship missile. The S-3B could also be fitted with "buddy stores", external fuel tanks that allowed the Viking to refuel other aircraft. In July 1988, VS-30 became the first fleet squadron to receive the enhanced capability Harpoon/ISAR equipped S-3B, based at NAS Cecil Field in Jacksonville, Florida. 16 S-3As were converted to ES-3A Shadows for carrier-based electronic intelligence (ELINT) duties. Six aircraft, designated US-3A, were converted for a specialized utility and limited cargo Carrier onboard delivery (COD) requirement. Plans were also made to develop the KS-3A carrier-based tanker aircraft, but this program was ultimately cancelled after the conversion of just one early development S-3A.
With the collapse of the Soviet Union and the breakup of the Warsaw Pact, the Soviet-Russian submarine threat was perceived as much reduced, and the Vikings had the majority of their antisubmarine warfare equipment removed. The aircraft's mission subsequently changed to sea surface search, sea and ground attack, over-the-horizon targeting, and aircraft refueling. As a result, the S-3B after 1997 was typically crewed by one pilot and one copilot [NFO]; the additional seats in the S-3B could still support additional crew members for certain missions. To reflect these new missions the Viking squadrons were redesignated from "Air Antisubmarine Warfare Squadrons" to "Sea Control Squadrons."
Prior to the aircraft's retirement from front-line fleet use aboard US aircraft carriers, a number of upgrade programs were implemented. These include the Carrier Airborne Inertial Navigation System II (CAINS II) upgrade, which replaced older inertial navigation hardware with ring laser gyroscopes with a Honeywell EGI (Enhanced GPS Inertial Navigation System) and added digital electronic flight instruments (EFI). The Maverick Plus System (MPS) added the capability to employ the AGM-65E laser-guided or AGM-65F infrared-guided air-to-surface missile, and the AGM-84H/K Stand-off Land Attack Missile Expanded Response (SLAM/ER). The SLAM/ER is a GPS/inertial/infrared guided cruise missile derived from the AGM-84 Harpoon that can be controlled by the aircrew in the terminal phase of flight if an AWW-13 data link pod is carried by the aircraft.
The S-3B saw extensive service during the 1991 Gulf War, performing attack, tanker, and ELINT duties, and launching ADM-141 TALD decoys. This was the first time an S-3B was employed overland during an offensive air strike. The first mission occurred when an aircraft from VS-24, from the USS Theodore Roosevelt (CVN-71), attacked an Iraqi Silkworm missile site. The aircraft also participated in the Yugoslav wars in the 1990s and in Operation Enduring Freedom in 2001.
The first ES-3A was delivered in 1991, entering service after two years of testing. The Navy established two squadrons of eight ES-3A aircraft each in both the Atlantic and Pacific Fleets to provide detachments of typically two aircraft, ten officers, and 55 enlisted aircrew, maintenance and support personnel (which comprised/supported four complete aircrews) to deploying carrier air wings. The Pacific Fleet squadron, Fleet Air Reconnaissance Squadron FIVE (VQ-5), the "Sea Shadows," was originally based at the former NAS Agana, Guam but later relocated to NAS North Island in San Diego, California, with the Pacific Fleet S-3 Viking squadrons when NAS Agana closed in 1995 as a result of a 1993 Base Realignment and Closure (BRAC) decision. The Atlantic Fleet squadron, the VQ-6 "Black Ravens," were originally based with all Atlantic Fleet S-3 Vikings at the former NAS Cecil Field in Jacksonville, Florida, but later moved to NAS Jacksonville, approximately 10 miles (16 km) to the east, when NAS Cecil Field was closed in 1999 as a result of the same 1993 BRAC decision that closed NAS Agana.
After the KA-6D
retirement the S-3B became the main aerial refueling aircraft
The ES-3A operated primarily with carrier battle groups, providing organic 'Indications and Warning' support to the group and joint theater commanders. In addition to their warning and reconnaissance roles, and their extraordinarily stable handling characteristics and range, Shadows were a preferred recovery tanker (aircraft that provide refueling for returning aircraft). They averaged over 100 flight hours per month while deployed. Excessive utilization caused earlier than expected equipment replacement when Naval aviation funds were limited, making them an easy target for budget-driven decision makers. In 1999, both ES-3A squadrons and all 16 aircraft were decommissioned and the ES-3A inventory placed in Aerospace Maintenance and Regeneration Group (AMARG) storage at Davis-Monthan AFB, Arizona.
In March 2003, an S-3 flew a rare mission against a land-based target. During Operation Iraqi Freedom, an S-3B Viking from Sea Control Squadron 38 (The "Red Griffins") piloted by Richard McGrath Jr. launched from USS Constellation (CV-64). The crew executed a time-sensitive strike and fired a laser-guided Maverick missile to neutralize a significant Iraqi naval and leadership target in the port city of Basra, Iraq. This was the first time an S-3 launched a laser-guided Maverick missile in combat.
On 1 May 2003, US President George W. Bush flew in the co-pilot seat of a VS-35 Viking from NAS North Island, California, to USS Abraham Lincoln off the California coast. There, he delivered his "Mission Accomplished" speech announcing the end of major combat in the 2003 invasion of Iraq. During the flight, the aircraft used the presidential callsign of "Navy One". The aircraft that President Bush flew in was retired shortly thereafter and on 15 July 2003 was accepted as an exhibit at the National Museum of Naval Aviation at NAS Pensacola, Florida.
Between July and December 2008 the VS-22 Checkmates, the last sea control squadron, operated a detachment of four S-3Bs from the Al Asad Airbase in Al Anbar Province, 180 miles (290 km) west of Baghdad. The planes were fitted with LANTIRN pods and they performed non-traditional intelligence, surveillance, and reconnaissance. After more than 350 missions, the Checkmates returned to NAS Jacksonville, Florida, on 15 December 2008.The squadron was disestablished on 29 January 2009.
's S-3B, callsign "Bloodhound 700", in 2010.
S-3B N601NA was operated by NASA
from 2009 to 2021.
A proposed airframe known as the Common Support Aircraft was advanced as a successor to the S-3, E-2, and C-2, but this plan failed to materialize. As the S-3 fleet was drawn down toward final retirement in 2009, Lockheed Martin performed a full-scale fatigue test and extended the service life of each remaining aircraft by about 11,000 flight-hours.
The final carrier-based S-3B squadron, VS-22, was decommissioned at NAS Jacksonville on 29 January 2009. Sea Control Wing Atlantic was decommissioned the following day, along with the last S-3s in frontline fleet service.
In June 2010 the first of three aircraft to patrol the Pacific Missile Test Center's range areas off of California was reactivated and delivered. The jet aircraft's higher speed, 10-hour endurance, modern radar, and a LANTIRN targeting pod allowed it to quickly confirm the test range being clear of wayward ships and aircraft before tests commence. These S-3Bs are flown by Air Test and Evaluation Squadron Thirty (VX-30) based out of NAS Point Mugu, California. Also, the NASA Glenn Research Center acquired four S-3Bs in 2005. Since 2009, one of these aircraft (USN BuNo 160607) has also carried the civil registration N601NA and is used for various tests.
By late 2015, the U.S. Navy had three Vikings remaining operational in support roles. One was moved to The Boneyard in November 2015, and the final two were retired, one stored and the other transferred to NASA, on 11 January 2016, officially retiring the S-3 from Navy service.
Naval analysts have suggested returning the stored S-3s to service with the U.S. Navy to fill gaps it left in the carrier air wing when it was retired. This is in response to the realization that the Chinese navy is producing new weapons that can threaten carriers beyond the range their aircraft can strike them. Against the DF-21D anti-ship ballistic missile, carrier-based F/A-18 Super Hornets and F-35C Lightning IIs have about half the unrefueled strike range, so bringing the S-3 back to aerial tanking duties would extend their range against it, as well as free up Super Hornets forced into tanking. Against submarines armed with anti-ship cruise missiles like the Klub and YJ-18, the S-3 would restore area coverage for ASW duties. Bringing the S-3 out of retirement could at least be a stop-gap measure to increase the survivability and capabilities of aircraft carriers until new aircraft can be developed for such purposes.
In October 2013, the Republic of Korea Navy expressed an interest in acquiring up to 18 ex-USN S-3s to augment their fleet of 16 Lockheed P-3 Orion aircraft. In August 2015, a military program review group approved a proposal to incorporate 12 mothballed S-3s to perform ASW duties; the Viking plan will be sent to the Defense Acquisition Program Administration for further assessment before final approval by the national defense system committee. Although the planes are old, being in storage kept them serviceable and using them is a cheaper way to fulfill short-range airborne ASW capabilities left after the retirement of the S-2 Tracker than buying newer aircraft. Refurbished S-3s could be returned to use by 2019. In 2017, the Republic of Korea Navy canceled plans to purchase refurbished and upgraded Lockheed S-3 Viking aircraft for maritime patrol and anti-submarine duties, leaving offers by Airbus, Boeing, Lockheed Martin, and Saab on the table.
In April 2014, Lockheed Martin announced that they would offer refurbished and remanufactured S-3s, dubbed the C-3, as a replacement for the Northrop Grumman C-2A Greyhound for carrier onboard delivery. The requirement for 35 aircraft would be met from the 91 S-3s currently in storage. In February 2015, the Navy announced that the Bell Boeing V-22 Osprey had been selected to replace the C-2 for the COD mission.
- First production version, 187 built.
- Upgraded avionics, AN/APS-137 inverse synthetic aperture radar, Joint Tactical Information Distribution System, AGM-84 Harpoon launch capability, first flight 13 September 1984, 119 converted from S-3As.
- The ES-3A Shadow was designed as a carrier-based, subsonic, all-weather, long-range, electronic reconnaissance (ELINT) aircraft. 16 aircraft were modified, replacing the EA-3B Skywarrior, and entering fleet service in 1993. The ES-3A carried an extensive suite of electronic sensors and communications gear, replacing the S-3's submarine detection, armament, and maritime surveillance equipment with avionics racks accommodating the ES-3A's sensors. These modifications had minor impact on airspeed, reducing its top rated speed from 450 KTAS to 405 KTAS but had no noticeable impact on the aircraft's range and actually increased its rated loiter time. Because these aircraft were standoff indications and warnings platforms and were never intended to be part of an ingress strike package, this new speed limitation was considered insignificant.
- Proposed dedicated air tanker with fuel capacity of 4,382 US gal (16,600 l), one converted from YS-3A, later converted to US-3A.
- Proposed air tanker based on S-3B and utilizing the buddy refueling system, not built.
- S-3A modified for carrier onboard delivery, capacity for six passengers or 4,680 lb (2,120 kg) of cargo, retired in 1998.
- Aladdin Viking
- Conversion of six aircraft for overland surveillance and Elint missions. May have dropped ground sensors in the Bosnian War.
- Beartrap Viking
- S-3Bs fitted with still-classified modifications.
- Calypso Viking
- Proposed anti-smuggling variant, not built.
- Gray Wolf Viking
- One aircraft fitted with AN/APG-76 radar in a modified cargo pod under the wing. Also dubbed SeaSTARS in reference to E-8 Joint STARS.
- Orca Viking
- Avionics testbed.
- Outlaw Viking
- One S-3B fitted with Over-the-horizon Airborne Sensor Information System (OASIS III), returned to regular S-3B in 1998. This particular Viking is now on display at the USS Midway Museum, located on the decommissioned USS Midway (CV-41).
- NASA Viking
- One aircraft was transformed into a state-of-the-art NASA research aircraft. The Navy's Fleet Readiness Center Southeast and a Boeing facility in Florida enhanced the plane by adding commercial satellite communications, global positioning navigation, and weather radar systems. They installed research equipment racks in what was once the plane's bomb bay. NASA's S-3B Viking was equipped to conduct science and aeronautics missions, such as environmental monitoring, satellite communications testing, and aviation safety research.
- United States
Aircraft on display
- 159404 – Celebrity Row, Davis-Monthan AFB (North Side), Tucson, Arizona.
S-3B on display at the Patuxent River Naval Air Museum
- 159387 – Navy One National Naval Aviation Museum, NAS Pensacola, Pensacola, Florida.
- 159412 – NAS North Island, San Diego, California.
- 159731 – USS Yorktown (CV-10) at the Patriot's Point Naval and Maritime Museum, Charleston, South Carolina.
- 159743 – Aviation Wing of the Marietta Museum of History, Dobbins ARB (formerly Atlanta NAS), Atlanta, Georgia.
- 159755 – NAS Pensacola, Pensacola, Florida.
- 159766 – USS Midway (CV-41) at San Diego, California.
- 159770 – Patuxent River Naval Air Museum, Lexington Park, Maryland.
- 160123 – Air Zoo at Kalamazoo, Michigan.
- 160599 – USS Hornet (CVS-12) at the former NAS Alameda, Alameda, California.
- 160604 – Pima Air and Space Museum (adjacent to Davis-Monthan AFB), Tucson, Arizona.
Data from Standard Aircraft Characteristics
- Crew: 4 (Pilot, Co-Pilot/COTAC, TACCO, Sensor Operator/TFO)
- Length: 53 ft 4 in (16.26 m)
- Wingspan: 68 ft 8 in (20.93 m)
- Width: 29 ft 6 in (8.99 m) folded
- Height: 22 ft 9 in (6.93 m)
- Height tail folded: 15 ft 3 in (5 m)
- Wing area: 598 sq ft (55.6 m2)
- Aspect ratio: 7.73
- Airfoil: root: NACA 0016.3-1.03 32.7/100 mod; tip: NACA 0012-1.10 40/1.00 mod
- Empty weight: 26,581 lb (12,057 kg)
- Gross weight: 38,192 lb (17,324 kg)
- Max takeoff weight: 52,539 lb (23,831 kg)
- Fuel capacity:
- Internal fuel capacity: 1,933 US gal (1,610 imp gal; 7,320 L) of JP-5 fuel
- External fuel capacity: 2 × 300 US gal (250 imp gal; 1,100 L) drop tanks
- Powerplant: 2 × General Electric TF34-GE-2 turbofan engines, 9,275 lbf (41.26 kN) thrust each
- Maximum speed: 429 kn (494 mph, 795 km/h) at sea level
- Maximum speed: Mach 0.79
- Cruise speed: 350 kn (400 mph, 650 km/h)
- Stall speed: 97 kn (112 mph, 180 km/h)
- Range: 2,765 nmi (3,182 mi, 5,121 km)
- Combat range: 460.5 nmi (529.9 mi, 852.8 km) 
- Ferry range: 3,368 nmi (3,876 mi, 6,238 km)
- Service ceiling: 40,900 ft (12,500 m)
- Rate of climb: 5,120 ft/min (26.0 m/s)
- Wing loading: 68.5 lb/sq ft (334 kg/m2)
- Thrust/weight: 0.353
- Up to 4,900 lb (2,220 kg) on 4 internal and 2 external hardpoints, including:
- The underwing hardpoints can also be fitted with unguided rocket pods or 300 US gal (1,136 L) fuel tanks.
- AN/APS-116 sea search radar, maximum range 150 nmi (173 mi, 278 km)
- OR-89 forward looking infrared (FLIR) camera with 3× zoom
- AN/ARS-2 sonobuoy receiver with 13 blade antennas on the airframe for precise buoy location (Sonobuoy Reference System)
- AN/ASQ-81 magnetic anomaly detector (MAD)
- AN/ALR-47 Electronic Support Measures (ESM) emitter-location system, with boxy receiver pods fitted to the wingtips, to locate adversary communications and radar transmitters
- AN/ASN-92 Inertial navigation system (INS) with doppler radar navigation and TACAN
- Up to 60 sonobuoys (59 tactical, 1 Search and Rescue)
Aircraft of comparable role, configuration, and era
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- ^ "S-3B Viking re-enters USN service in test range surveillance role." Janes.com. Retrieved: 13 March 2015.
- ^ "NASA Retires a Research Workhorse". NASA. 8 July 2021. Retrieved 12 July 2021.
- ^ Francillon 1982, pp. 455–456.
- ^ a b Godfrey 1974, p. 6.
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- ^ Waldron, Greg (18 October 2017). "ADEX: Big MPAs hunt for Seoul maritime requirement". FlightGlobal. Seoul. Archived from the original on 19 October 2017. Retrieved 19 October 2017.
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- ^ "S-3 Viking 159412." aerialvisuals.ca Retrieved: 8 July 2015.
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- ^ "S-3 Viking/160599." USS Hornet Museum. Retrieved: 8 July 2015.
- ^ "S-3 Viking/160604." Pima Air and Space Museum. Retrieved: 8 July 2015.
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