Along with the 141 E-2Cs produced for the USN, the Hawkeye has had considerable export success. No less than six foreign governments have bought them: Israel (four), Egypt (six), France (two for their new carrier Charles de Gaulle), Japan (thirteen), Singapore (four), and Taiwan (four). There are more Hawkeyes in use throughout the world than any other AEW aircraft ever built.
There also has been one major variant of the Hawkeye, a transport version known as the C-2A Greyhound. Basically an E-2 airframe with a broader fuselage and the radar rotodome deleted, it can deliver cargo and passengers hundreds of miles/kilometers out to sea. Known as a COD (for Carrier Onboard Delivery) aircraft, it replaced the elderly C-1 Trader, which is itself a variant of the earlier E-1 Tracker. With its broad rear loading ramp and fuselage, the C-2 can carry up to twenty-eight passengers, twenty stretcher cases, or cargo up to the size of an F-110 engine for the F-14.
The Hawkeye has had a long run in USN service. The original -A model was first flown in October 1960, to provide early warning services for the new generation of supercarriers then coming into service. In January 1964, the first of fifty-nine E-2As were delivered to their squadrons, and were shortly headed into combat in Southeast Asia. These were later updated to the E-2B standard, which remained in use until replaced by the E-2C in the 1970’s. The first E-2Cs entered USN service with Airborne Early Warning Squadron (VAW) 123 at NAS Norfolk, Virginia, in November of 1973. The -C-model Hawkeye was produced in order to provide the F-14 Tomcat with an AEW platform matched to the new fighter’s capabilities. Though visually identical to the earlier models, the E-2C was equipped with new-technology digital computers that provided a greatly increased capability for the new Hawkeye. These gave the operators the ability to track and intercept the dozens of Soviet bombers and hundreds of ASMs and SSMs that were expected to be fired at CVBGs if the Cold War ever turned “hot.”
E-2C Hawkeye AEW aircraft on the deck of the USS George Washington (CVN-73). They generally parked alongside the island structure, on a spot called “the Hummer Hole.”
JOHN D. GRESHAM
In any event, the E-2Cs never directed the massive air battles they had been designed for. Instead, the Hawkeye crews spent the declining years of the Cold War flying their racetrack patterns over the fleets, maintaining their lonely vigil for a threat that never came. Carrier-based Hawkeyes were not strangers to combat, however. E-2Cs guided F-14 Tomcat fighters flying combat air patrols during the 1981 and 1989 air-to-air encounters with the Libyan Air Force, as well as the joint USN/USAF strike against terrorist-related Libyan targets in 1986. Israeli E-2Cs provided AEW support during their strikes into Lebanon in 1982, and again during the larger invasion the following year. More recently, E-2Cs provided the command and control for successful operations during the Persian Gulf War, directing both land strike and CAP missions over Iraq and providing control for the shoot-down of the two Iraqi F-7/MiG-21 fighters by carrier-based F/A-18’s. E-2 aircraft have also worked extremely effectively with U.S. law enforcement agencies in drug interdictions.
Today the entire Hawkeye fleet is being upgraded under what is called the Group II program. Along with thirty-six new-production aircraft, the entire USN E-2C fleet is being given the improved APS-145 radar, new computers, avionics, data links, and a GPS/INS system to improve flight path and targeting accuracy. This means that a single Hawkeye can now track up to two thousand targets at once in a volume of six million cubic miles of airspace and 150,000 square miles of territory. Current plans have the Hawkeye/ Greyhound fleet serving until at least the year 2020, when a new airframe known as the Common Support Aircraft (CSA) will be built in an AEW version. By that time, the basic E-2 airframe will have served for almost six decades!
A VS-32 S-3B Viking ASW aircraft on the deck of the USS George Washington (CVN-73) with wings folded. The S-3B has rapidly taken over many critical roles in carrier operations, espcially in-flight refueling of other aircraft.
JOHN D. GRESHAM
Lockheed Martin S-3B Viking: The Vital “Hoover”
Antisubmarine warfare (ASW) is probably the most complex, frustrating, operationally challenging, and technically secretive mission that any aircraft can be called upon to perform. To locate, track, classify, and destroy a target as elusive as a nuclear submarine in the open ocean often seems virtually impossible. And against a quiet modern diesel boat in noisy coastal waters, the odds are even worse. In fact, the ASW mission doesn’t have to be that successful. It has succeeded as long as enemy subs are forced to go deep, run quiet, and keep their distance from a Naval task force or convoy. It is a matter of record that the most effective weapon against submarines during the Second World War was the ASW patrol aircraft. Such aircraft have continued to do this job ever since.
Today, the USN operates two fixed-wing ASW aircraft. One is the venerable four engined P-3C Orion, which operates from land bases. The other is its “little brother” from the Lockheed Martin stable, the S-3B Viking, which is carrier-capable. Airborne ASW has long been a Lockheed specialty. Their land-based Hudson and Ventura patrol bombers played a key role in World War II against German U-boats. More recently, their P-2V Neptune and P-3 Orions have kept vigil over the world’s oceans, watching for everything from submarines to drug-running speedboats. The so-called “sea control” mission is thankless work, with nearly day-long missions, most of which are flown over inhospitable and empty seas. The boredom arising from these missions in no way reduces their importance. A maritime nation that cannot monitor and control the sea-lanes it uses is destined to sail at the whims of other powers.
Early on, carrier aviators knew that they too needed the services of such aircraft, and began to build specially configured ASW/patrol aircraft shortly after the end of World War II. The first modern carrier-based ASW aircraft was Grumman’s twin-engine S-2 Tracker, which entered service in 1954 and remained in the fleet for over twenty-five years with more than six hundred built.54 In 1967, the growing sophistication of the Soviet submarine threat led the Navy to launch a competition for a radically new generation of carrier ASW aircraft. Known as the VSX program, it was designed both to replace the Tracker and to provide a utility airframe for other applications. In 1969, the design submitted by Lockheed and Vought was declared the winner and designated S-3. The prototype S-3A first flew on January 21 st, 1971, and the type entered service in 1974 with VS-41 at NAS North Island, California. By the time S-3A production ended in 1978, 179 had been delivered.
The S-3 Viking is a compact aircraft, with prominent engine pods for its twin TF-34-GE-2 engines. This is the same basic non-afterburning turbofan used on the Air Force’s A-10 “Warthog,” and its relatively quiet “vacuum-cleaner” sound gives the Viking its nickname: the “Hoover.” The crew of four sits on individual ejection seats, with the pilot and copilot in front, and the tactical coordinator (TACCO) and sensor operator (SENSO) in back. A retractable aerial refueling probe is fitted in the top of the fuselage, and all S-3B aircraft are capable of carrying an in-flight refueling “buddy” store. This allows the transfer of fuel from the Viking aircraft to other Naval aircraft. Because ASW is a time-consuming business that requires a lot of patience and equipment, the Viking is relatively slow, with a long range and loiter time. This means the S-3 is pretty much a “truck” for the array of sensors, computers, weapons, and other gear necessary to find and hunt submarines. But don’t think that the Viking is a sitting duck for anyone with a gun or AAM. The S-3 is surprisingly nimble, and it’s able to survive even in areas where AAW threats exist.
There are three primary ways to find a submarine that does not want to be found. You can listen for sounds, you can find it magnetically (something like the way compass needles find north), or you can locate a surfaced sub with radar. Since sound waves can travel a long way underwater, a sub’s most important “signature” is acoustic. But how can an aircraft noisily zooming through the sky listen for a submarine gliding beneath the waves? The answer, developed during World War II, is the sonobuoy. T
his is an expendable float with a battery-powered radio and a super-sensitive microphone. “Passive” sonobuoys simply listen. “Active” sonobuoys add a noise-makerthat sends out sound waves in hope of creating an echo. By dropping a pattern of sonobuoys and monitoring them, an ASW aircraft can spread a wide net to catch the faint sounds of the sub’s machinery, or even the terrifying “transient” of a torpedo or missile launch.
Another detectable submarine signature is magnetism. Since most submarines are made of steel, they create a tiny distortion of the earth’s magnetic field as they move.55 The distortion is very small, but it is detectable. A “magnetic anomaly detector” (MAD) can sense this signature, but it is so weak that the aircraft must practically fly directly over the sub at low altitude to do so.56 In order to isolate the MAD from the plane’s own electromagnetic field, it is mounted on the end of a long, retractable “stinger” at the tail of the aircraft.
Eventually, every submarine must come to periscope depth to communicate, snorkel, or just take a quick look around. Although periscope, snorkel, and communications masts are usually treated with radar-absorbing material, at close range sufficiently powerful and sensitive radar may obtain a fleeting detection. Finally, there are more conventional means of detection. For example, an airborne receiver and direction finder may pick up a sub’s radio signals, if it is foolish or unlucky enough to transmit when an enemy is listening. And sometimes the telltale “feather” from a mast can be seen visually or through an FLIR system.
The integrated ASW package of the initial version of the Viking, the S-3A, was designed to exploit all of these possible detection signatures. Sixty launch tubes for sonobuoys are located in the underside of the rear fuselage. In addition, the designers provided the ASQ-81 MAD system, an APS-116 surface search radar, a FLIR system, a passive ALR-47 ESM system to detect enemy radars, and the computer systems that tie all of these together. Once a submarine has been found, it is essential that all efforts be made to kill it. To this end, the S-3 was not designed to be just be a hunter; it was also a killer. An internal weapons bay can accommodate up to four Mk. 46 torpedoes or a variety of bombs, depth charges, and mines. Two wing pylons can also be fitted to carry additional weapons, rocket pods, flare launchers, auxiliary fuel tanks, or a refueling “buddy store.”
All this made the S-3A one of the best sub-hunting aircraft in the world, which was good enough in its first decade of service. By 1981, though, the -A model Viking clearly needed improvement in light of the growth in numbers and capabilities of the Soviet submarine fleet. In particular, the improved quieting of the Russian boats made hunting even more of a challenge. In order to improve the S-3’s avionics, sonobuoy, ESM and radar data processing, and weapons, a conversion program was started. The result was the S-3B, which upgraded basic -A model airframes to the new standard. The first S-3Bs began to arrive in the fleet in 1987, and they quickly showed both their new sea control abilities and capability to fire AGM-84 Harpoon antiship missiles. This is the version that serves today.
The prototype ES-3A Shadow on a test flight. The sixteen Shadows provided the fleet with electronic reconnaissance and surveillance services until recently.
JOHN D. GRESHAM
One of the original hopes for the S-3 was to provide a basic airframe for a number of other aircraft types. Unfortunately, the small production run of the Viking has limited its opportunities for other roles. A small number of early S-3As were modified by removing all the ASW equipment and fittings for armament, allowing them to carry urgent cargo and mail and providing seats for a crew of three and up to six passengers (with minimal comfort). Designated US-3A and possessing a much longer range than the normal C-2A Greyhound COD aircraft, a total of five served in the Pacific fleet until they were recently retired. A dedicated tanker version, the KS-3A, was tested in 1980, but never went into production.
The single most important variant was the ES-3A “Shadow,” an electronic surveillance (ESM) and signals intelligence (SIGINT) platform, which replaced the venerable EKA-3B “Electric Whale.” Externally, the Shadow is quite distinctive, with a prominent dorsal hump and a retractable radome. About 3,000 lb/1,360 kg of ASW gear was removed and 6,000 lb/2,721 kg of electronics were packed into the weapons bay. While the Shadow is unarmed, it can also carry external fuel tanks and “buddy” refueling stores. Sixteen of these aircraft are split between two squadrons: VQ-5 (the “Sea Shadows”) in the Pacific Fleet and VQ-6 (the “Ravens”) in the Atlantic. Detachments of two or three aircraft normally deploy with every carrier air group, providing ESM, SIGINT, and OTH support for the CVBG. Unfortunately, recent budget cuts have targeted the shadow community which appears to be headed for disestablishment. Plan on seeing the ES-3 head for the boneyard in 1999.
The S-3 community has changed a great deal since the end of the Cold War. As long as the Soviet Union maintained the world’s largest submarine fleet, the ASW squadron was an integral part of the carrier air group. But today, that “blue-water” submarine threat has receded. This hardly means that the S-3’s can be retired and their crews given pink slips. On the contrary, the VS squadrons have taken on a whole new set of roles and missions, making them more valuable than ever. After the premature retirement of the KA-6D fleet in 1993, they took on still another role, becoming the primary aerial refueling tanker for the CVW. This has not proved to be the best solution to the aerial refueling problem, since an S-3B can only off-load about 8,000 lb/3,628 kg of fuel, as compared to over 24,000 lb/10,886 kg for the KA-6D. With the thirsty F/A-18’s needing at least 4,000 lb/1,814 kg every time they go on a long CAP or strike mission, even the ES-3 Shadows are being used as tankers! To reflect all this, the previous ASW designation of their squadrons has been changed to “Sea Control,” which uses the “VS” nomenclature.
The S-3B community currently includes ten operational squadrons, administratively divided between two Sea Control Wings: one for the Atlantic Fleet and one for the Pacific. A single Fleet Replacement Squadron, VS-41, based at North Island NAS, California, serves as the advanced training unit. During Operation Desert Shield and Desert Storm, S-3 squadrons flew maritime patrols to help enforce sanctions against Iraq. In fact, the only complaint I’ve ever heard about this wonderful aircraft is that the Navy bought too few of them. Another two hundred would have been invaluable today, but the poor choices on the part of naval aviation leaders scuttled that idea. At the end of 1997, about 120 S-3’s remained in service. Eventually, all of their tasks will be taken over by the future Common Support Aircraft that is scheduled to enter service around 2015.
Sikorsky H-60 Seahawk: A Family of Winners
Fixed-wing aircraft that hunt submarines on the prowl have one major vice: They move too fast. One solution is to use an aircraft that can stand still, dip a sonar into the water, and just listen for a while, the way a surface ship or submarine can. Then, if needed, it can rapidly dash to another spot, and do it all again. In other words, you need ASW helicopters. The Germans were the first to use helicopters for this purpose. During World War II they used them to hunt Russian submarines in the Baltic Sea. Following the war, it was only a matter of time and technological development until a true ASW helicopter was developed. After several false starts in the 1950’s, Sikorsky developed the SH-3 Sea King. One of the finest helicopters ever built, it was equipped with a dipping sonar and homing torpedoes, and had plenty of range and power. However, by the mid-1970’s it was clear that the old SH-3 was heading into its last legs as the USN’s premier sub-hunting helicopter.
Meanwhile, the USN had operated another fleet of ASW choppers, so-called “light” helicopters, which can operate off small platforms on escort ships. Starting in the late-1960’s, this mission was filled by the Kaman SH-2 Seasprite LAMPS I (Light Airborne Multi-Purpose System). For three decades ,SH-2’s have operated off the Navy’s smallest ships (such as the now-retired Knox-class (FF-1052) frigates), and are still being produced for foreign navies. While the SH-2 was a good start, it lacked the range and payload
to hunt front-line Soviet submarines. The Navy wanted a LAMPS helicopter that could hunt the new generation of Soviet submarines coming into service, and began development in the early 1970s.
In 1977, the Navy awarded a contract to IBM Federal Systems and Sikorsky to build a new light ASW helicopter system called Light Airborne Multi-Purpose System—Mark III (LAMPS III).57 The helicopter itself was called the SH-60B Seahawk. The SH-60B was developed from Sikorsky’s UH-60 Blackhawk transport helicopter, which had recently won the Army’s competition to replace the venerable UH-1 “Huey.”58 This saved a lot of development money for the Navy and gave them an airframe with excellent growth potential.
Equipped with sonobuoys, MAD, radar, and other detection gear, the SH-60B would be the helicopter equivalent of the S-3B for escort ships. The LAMPS III birds would be based aboard the new generation of Ticonderoga-class (CG-47) Aegis cruisers, Spruance (DD-963) and Kidd-class (DDG-993) destroyers, and Oliver Hazard Perry-class (FFG-7) frigates. These ships were being designed with enlarged helicopter hangars and landing platforms, and a combat center with two-way data links to process information from the SH- 60’s onboard sensors. When they first deployed in 1984, the LAMPS III-CAPABLE ships were the most powerful ASW escorts in the world. In a task force or convoy, they would form an “outer zone” barrier against any submarines trying to attack.