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War Hoover: The Fabulously Flexible Lockheed S-3 Viking

Calls for the Viking’s Return Have So Far Not Been Answered, But Fans Can Still Hope

VS-37 S-3A. Image via US Navy

Lockheed’s S-3 Viking carrier-based antisubmarine aircraft was developed to replace the venerable Grumman S-2 Tracker. To replace a versatile and frankly well-liked aircraft like the Tracker would take an excellent aircraft in its own right; one with not only next-level technology but also ground-breaking capabilities for carrier-based antisubmarine warfare (ASW). The thing was, even though Lockheed land-based aircraft had been flying ocean surveillance missions for decades, Lockheed hadn’t delivered a carrier-based aircraft since the T2V-1 Seastar trainer. Sure they had tried, but Grumman, Vought, Douglas, and North American had owned carrier aviation for many years.

VS-21 S-3A with VS-37 S-2G. Image via US Navy

Lockheed decided to bring Vought (by now Ling-Temco-Vought or LTV) in on their proposal for the US Navy’s VSX requirement during the mid-1964. The aircraft the two companies came up with borrowed from Vought’s Corsair II (nose landing gear), Crusader (main landing gear). Vought was also tasked with designing the folding wings and empennage. Lockheed owned the overall design and integration, General Electric the engines, and Sperry Univac got the contract to develop the aircraft’s next-level integrated sensor suite. General Dynamics teamed with Grumman to develop their VSX design (Model 21). Ironically both Grumman and Vought developed their own VSX designs as well. McDonnell Douglas submitted a pair of VSX designs too. The final design entries were submitted by the end of December 1968.

VS-21 S-3A. Image via US Navy

On 4 August 1969, Lockheed’s design was selected as the winner of the VSX contest and designated S-3A. Eight YS-3A prototypes were ordered, the first of which (Navy Bureau of Aeronautics Number of BuNo 157992 flew on 21 January 1972. The development and test phases of the program went remarkably well. The Lockheed/LTV/Sperry/GE team was able to meet or exceed the development milestones and delivered the aircraft on time and within budget- an almost unheard of phenomenon in those days and the days since. To top it all off, the scheduled crew training start date, the initial operational capability (IOC) date, and the initial carrier deployment date were all met or exceeded.

East Coast S-3As. Image via US Navy

All the more impressive was the fact that the YS-3A was an entirely new airframe with new engines, the first computer system of its kind, the first crew ejection system of its kind, the first carrier-based AW platform to be inflight refueling capable, the first to be able to execute a missed carrier approach (bolter) with an engine out, the first to include a fully Automatic Carrier Landing System (ALCS) with auto-throttle, the first with a 60 store sonobuoy capacity, the first to be capable of descending from 30,000 feet altitude to seal level in two minutes, the first to be equipped with an auxiliary power unit (APU), and the first to eliminate paper from the sensor data analysis process.

VS-41 S-3A. Image via US Navy

Production of S-3A Viking aircraft began at Lockheed’s Burbank production facility in 1974 and fleet S-3As entered service with Air Antisubmarine Warfare Squadron FOUR ONE (VS-41) Shamrocks on 20 February 1974. VS-41 was the S-3 Fleet Replacement Squadron (FRS) or RAG until East Coast squadron VS-27 Pelicans/Sea Wolves was tasked with East Coast RAG duty during the 1980s. The first operational fleet squadron to gain IOC with the Viking was VS-21 Fighting Red Tails. VS-21 was also the first to deploy with the Viking when they went aboard the carrier USS John F Kennedy (CVA-67) with CVW-1 for the carrier’s 1975-1976 Mediterranean Sea deployment. Fleet S-3A Vikings blew through 100,000 flight hours less than two years after the Red Tails first took the Viking on that first Med Cruise.

VS-31 S-3A. Image via US Navy

Lockheed built a total of 187 S-3 Vikings (including those eight prototypes) between 1971 and 1978. Vikings equipped a total of 18 Navy squadrons. The East Coast home of the Vikings was NAS Cecil Field near Jacksonville in Florida. After the Navy moved out of Cecil, East Coast VS units were based at NAS Jacksonville. West Coast VS squadrons were shore based with VS-41 at NAS North Island in San Diego. During their 42 years in service Lockheed Vikings flew for nearly 1.7 million flight hours. Fleet Vikings were retired and sent to the 309th Aerospace Maintenance and Regeneration Group (AMARG) at Davis-Monthan Air Force Base (AFB) near Tucson in Arizona. Many of those aircraft remain in storage today.

VS-33 S-3A. Image via US Navy

The Viking was crewed by four- a pilot, a co-pilot, a tactical coordinator (TACCO) seated on the starboard side aft and an enlisted aviation antisubmarine warfare operator (AW) or SENSO seated on the port side aft. All four crew positions were equipped with upward-firing Douglas Escapac E-1 zero-zero ejection seats. The seats could be ejected in group sequence or the rear seats individually. Rear seat ejection sequences included automatic stowage of the keyboard shelves in front of the TACCO and SENSO. Front seat ejection was through the top of the canopy on either side of the retractable refueling probe; rear seats fired through special panels built into the crew cabin overhead. Crew entry into the Viking was via a small low-mounted entry door on the starboard side of the aircraft.

VS-29 S-3A. Image via US Navy

The S-3’s folding wings were high-mounted on its fuselage with leading edges swept at 15 degrees. The wings had leading edge slats and trailing edge Fowler flaps along with spoilers mounted on both the upper and the lower surfaces. Control surfaces on the wings and swept empennage were all hydraulically actuated. Viking empennages were conventional swept surfaces featuring a folding vertical stabilizer. S-3s were powered by a pair of General Electric TF34 twin-shaft high-bypass turbofan engines putting out 9,065 pounds of thrust, providing the Viking with 2,300 miles of range- extendable via aerial refueling. The engines were mounted in nacelles under the inner wings close to the fuselage to facilitate the folding wings. TF34 engines powered only one other production military aircraft: The Fairchild Republic A-10 Thunderbolt II. The distinctive sound of the TF34s bestowed on the jet’s iconic nickname- Hoover.

VS-32 S-3A. Image via US Navy

Under the wings outboard of the engines and inside the wing fold the Viking was equipped with two underwing pylons from which 1,500 pounds worth of drop tanks, ordnance such as general purpose and cluster bombs, missiles, rockets, and storage pods could be hung per pylon. The internal bomb bay could also be used to tote 4,000 pounds of general purpose bombs along with aerial torpedoes and “special” stores like the B57 and B61 atomic bombs. In the Hoover’s belly were the 59 ASW sonobuoy chutes with a single dedicated search and rescue (SAR) chute. The Texas Instruments AN/ASQ-81magnetic anomaly detection (MAD) sensor was mounted on an extendable boom in the tail of the Viking. The Viking countermeasures system was the ALE-39 system featuring the ability to deploy up to 90 rounds of flares, chaff, or expendable jammers from the aircraft’s three dispensers.

VS-31 S-3A. Image via US Navy

Four man Hoover crews were able to excel thanks in large part to that Sperry General Purpose Digital Computer (GPDC) and its integrated sensor suite. Unlike Lockheed’s P-3 Orion or the previous Grumman S-2 Tracker, there were no paper traces with scrawled annotations or calipers aboard Hoovers. The SENSO and TACCO could display data from any of the onboard sensor systems on their multi-purpose displays (MPDs). Able to shift workloads between stations and monitor the take from everything at once made Viking crews efficient and flexible. It is a tribute to the mission systems in the Viking that the Canadians chose the same core mission system to equip their P-3 Orion-derived Lockheed CP-140 Aurora ASW aircraft.

VS-24 S-3A. Image via US Navy

The S-3A Viking sensor suite included the Texas Instruments (TI) AN/APS-116 three mode sea search radar in the nose of the jet, the TI OR-89 Forward Looking Infrared (FLIR) imager mounted in a retractable turret on the port side of the aircraft,  the IBM AN/ALR-47 Electronic Support Measures (ESM) emitter-location system housed in wingtip receiver pods, the AN/ARS-2 sonobuoy receiver system featuring a total of 13 blade antennae sprouting from several locations on the airframe, and the computer that tied it all together:  a Univac 1832 (AN/AYK-10) digital processor, itself an improved version of the Univac 1831 found in the Lockheed P-3C Orion. Additional black boxes in the jet included encrypted UHF and HF radios and datalink, identification friend or foe (IFF) and the Litton AN/ASN-92 inertial navigation system (INS) along with a TACAN radio beacon navigation system and a Doppler navigation radar. Finally, the Viking also carried a radar altitude warning system and an automatic carrier landing system with autothrottle.

S-3B demonstrator. Image via US Navy

During the mid-1980s S-3A Vikings were being looked at to take on roles in the fleet that aircraft like the Douglas KA-3B Skywarrior were leaving unfilled when retired. Modifications of 119 S-3A aircraft to S-3B specification began in 1987. The B Hoover was equipped with new and/or improved radar, ESM, and FLIR sensors; the improved AN/ARR-78 sonobuoy receiver system, the AN/UYS-1 Proteus acoustic signal processor, the Joint Tactical Information Datalink System (JTIDS), and revised  radios. Ability of pass gas to other aircraft was added via D-704 or similar refueling pods. Now capable of finding targets with inverse synthetic aperture radar (ISAR) and taking them down with the McDonnell Douglas AGM-84 Harpoon missile, Hoovers soon earned the revised sobriquet of War Hoover. S-3Bs entered service with VS-30 Diamondcutters in July of 1988. Nearly all operational S-3As were reworked to bring them up to S-3B specs, except for the six airframes modified as long-range COD US-3As and 16 modified as ES-3A Shadow electronic intelligence (ELINT) aircraft. Studies into a dedicated tanker version of the S-3, designated KS-3A, were made but cancelled after a single airframe was converted.

VS-21 S-3Bs. Image via US Navy

Somewhat ironically when the Cold War came to a close and Grumman KA-6D Intruder tankers were retired, multi-purpose Hoovers largely became single-purpose Texaco Hoovers. Fleet Vikings were no longer seen as needed for antisubmarine work and had the majority of their ASW mission equipment and their SENSOs and TACCOs removed. Occasionally tasked with surface search, sea and ground attack, over-the-horizon targeting, or refueling work, after 1997 Hoovers were typically crewed by a pilot and a co-pilot only, though for special tasking the unused crew stations could be occupied as necessary. Even the names of the squadrons flying Vikings changed from Air Antisubmarine Warfare Squadrons to Sea Control Squadrons. Fleet Hoovers passed so much gas their squadron designations could have been changed to VSK.

VS-33 S-3B. Image via US Navy

When the Desert Shield and Desert Storm came along, War Hoovers earned their keep. By then modified with improved avionics and able to employ AGM-65E or AMG-65F Maverick missiles and standoff land attack missiles like the AGM-84H/K Stand-off Land Attack Missile Expanded Response (SLAM/ER), War Hoovers flew land and sea attack and simple ELINT missions- and still passed plenty of gas. War Hoovers also launched ADM-141 Tactical Air Launched Decoys (TALDs) and sank Iraqi patrol boats. A VS-24 Scouts S-3B War Hoover took out an Iraqi Silkworm missile site. War Hoovers also flew sorties in the Med during the 1990s and during Enduring Freedom. During Iraq II a VS-38 Red Griffins S-3B heavily damaged Saddam’s yacht at Basra with a laser-guided Maverick. Also in 2003 a VS-35 Blue Wolves jet briefly became Navy 1 when President George W. Bush trapped aboard the carrier USS Abraham Lincoln (CVN-72).

Navy 1 traps on the Lincoln. Image via US Navy

Interesting Viking variants included the Aladdin Viking– six S-3Bs converted for overland surveillance and ELINT missions. Aladdin Vikings are rumored to have dropped ground sensors during the Bosnian War. Beartrap Vikings were specialized ASW Hoovers with still-classified mods. The Calypso Viking was to be a dedicated anti-smuggling platform but never got out of the discussion stage. The single Gray Wolf Viking was equipped with a pylon-mounted Norden AN/APG-76 radar pod and sometimes referred to as SeaSTARS. The Orca Viking was Lockheed’s avionics testbed aircraft. The Outlaw Viking, an S-3B modified with the Over-the-horizon Airborne Sensor Information System (OASIS III), was reworked to S-3B standards and now adorns the deck of the museum carrier USS Midway.

S-3Bs. Image via US Navy

Some of the last War Hoover combat sorties were flown by VS-22 Checkmates from Al Asad airbase about 180 miles west of Baghdad during December of 2008. The four S-3B Vikings were fitted with AN/AAQ-13 Low Altitude Navigation and Targeting for Night (LANTIRN) pods. The jets were said to be performing non-traditional intelligence, surveillance, and reconnaissance (NTISR). VS-28 returned to NAS Jacksonville from the sandbox on 15 December 2008. The Checkmates were no more less than two months later. VS-22, the last operational Viking squadron, was decommissioned on 29 January 2009. Sea Control Wing Atlantic was decommissioned the next day. VX-30 Bloodhounds operated the last Vikings in the Navy out of NAS Point Mugu up until 2016. The National Aeronautics and Space Administration (NASA) still flies a Hoover or two.

NASA 601. Image via NASA

Those Hoovers stored in the desert are mostly low-time airframes with plenty of life left in them. Over the years since their retirement their inherent flexibility and efficiency have been mentioned in discussions about replacement COD aircraft, dedicated refueling platforms to stretch fleet legs, and giving them their old ASW jobs back. After all, Super Hornets make such splendid tankers! The South Koreans expressed interest in buying some of the retired Hoovers to replace their own turbine-powered S-2 Trackers. Modified S-3Bs were again mentioned as replacement COD aircraft but the Navy selected the Bell-Boeing CMV-22B instead. Once dubbed the Swiss Army Knives of Naval Aviation, the Vikings are still waiting for another shot out there in the desert. We kind of hope they get one.

VS-33 S-3A. Image via US Navy

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Bill Walton

Written by Bill Walton

Bill Walton is a life-long aviation enthusiast and expert in aircraft recognition. As a teenager Bill helped his engineer father build an award-winning T-18 homebuilt airplane in their Wisconsin basement. Bill is a freelance writer, an avid sailor, engineer, announcer, husband, father, uncle, mentor, coach, and Navy veteran. Bill lives north of Houston TX with his wife and son under the approach path to KDWH runway 17R, which means they get to look up at a lot of airplanes. A very good thing.

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