The Northrop Grumman (formerly Grumman) EA-6B Prowler is a twin-engined, four-seat, mid-wing electronic-warfare aircraft. Operated by both the United States Marine Corps and United States Navy between 1971 and 2019, it was derived from the A-6 Intruder airframe.
The aircraft's immediate predecessor, the EA-6A, was an interim conversion of the A-6 airframe to perform electronic warfare missions during the 1960s. In 1966, work on the more advanced EA-6B commenced. It featured an enlarged, four-seat cockpit, a fully integrated electronic-warfare system, and advanced electronic countermeasures. Furthermore, it was suitable for long-range, all-weather, carrier-based operations in addition to land-based uses. Typically, the aircrew of an EA-6B consisted of a single pilot and three electronic countermeasures officers, though having only two ECMOs on missions was not uncommon. It was capable of firing anti-radiation missiles (ARMs), such as the AGM-88 HARM. Although designed as an electronic-warfare and command-and-control aircraft for air strike missions, the EA-6B was also capable of attacking some surface targets on its own, in particular enemy radar sites and surface-to-air missile launchers. In addition, the EA-6B was capable of gathering electronic signals intelligence.
On 25 May 1968, the EA-6B performed its maiden flight; three prototypes were converted from A-6As, while five EA-6Bs participated in the development program. During July 1971, Tactical Electronic Warfare Squadron 132 (VAQ-132) became the first operational squadron to be equipped with the type; the EA-6B's first combat deployment took place 11 months later in the latter half of the Vietnam War. It frequently carried out electronic-warfare operations, such as the jamming of enemy radar systems, as well as the gathering of radio intelligence on enemy radar and air defense systems. The EA-6B also played an active role during the 1983 invasion of Grenada, Operation El Dorado Canyon (Libya, 1986), Operation Praying Mantis (Iran, 1988), and Operation Desert Storm (Iraq, 1991). It also was called on during the Operation Enduring Freedom (Afghanistan, 2001–2014) and Operation Inherent Resolve (Iraq, 2014), in addition to other lower-intensity duties.
By the 21st century, efforts to eventually replace the EA-6B had been launched, such as the abortive Common Support Aircraft initiative. As a result of the type being heavily used during its lengthy service life, the EA-6B had become a relatively high-maintenance aircraft during its latter years of service. Nevertheless, it had undergone frequent equipment upgrades throughout its service life;Hansen 2006, p. 8. major programs included the Advanced Capability EA-6B and the Improved Capability (ICAP) II schemes. The type's final overseas deployment occurred in late 2014; the EA-6B was withdrawn from U.S. Navy service in June 2015, while the U.S. Marine Corps retired its last aircraft in March 2019. It has been effectively succeeded by the EA-18G Growler, an electronic-warfare derivative of the F/A-18F Super Hornet.
Development
Origins By the 1960s, the United States Marine Corps (USMC) was operating several aging electronic countermeasure (ECM) platforms, including the EF-10B Skyknight and AD Skyraider. The service sought to procure more modern platforms; this desire led to the development of the EA-6A "Electric Intruder". The EA-6A was a direct conversion of the standard Grumman A-6 Intruder airframe, equipped with a twin-seat cockpit along with assorted electronic-warfare (EW) equipment. During December 1965, the EA-6A entered squadron service with the USMC; shortly thereafter, it saw action in Operation Rolling Thunder during the Vietnam War. In total, three USMC squadrons were equipped with the type in the conflict; 27 EA-6As were produced, 15 of which were newly manufactured, while the others were conversions. The majority of these EA-6As were retired from service in the 1970s; the final handful of aircraft were operated by two electronic-attack "aggressor" squadrons of the United States Navy (USN). These last examples were finally retired during the 1990s. The EA-6A was essentially an interim warplane until the more-advanced EA-6B could be designed and built.
During 1966, development of the EA-6B, a substantially redesigned and more advanced model, commenced as a replacement for the EKA-3B Skywarriors then being operated by the USN. The redesign included the lengthening of the forward fuselage to create a rear area that accommodated a larger four-seat cockpit, while an antenna fairing was added to the tip of the vertical stabilizer. The EA-6B was powered by a pair of Pratt & Whitney J52 turbojet engines, which enabled it to attain high subsonic speeds.Hansen 2006, p. 10. On 14 November 1966, Grumman was awarded a $12.7 million contract to develop an EA-6B prototype. On 25 May 1968, the EA-6B performed its maiden flight;Sweetman 2002, p. 8. it entered regular service on aircraft carriers during July 1971.Eden and Moeng 2002, p. 1152. Three prototype EA-6Bs were converted from A-6As, and five EA-6Bs were developmental airplanes. Between 1966 and 1991, 170 EA-6B production aircraft were manufactured.
The EA-6B was continually upgraded over the years. The first such upgrade was named "expanded capability" (EXCAP) beginning in 1973. Then came "improved capability" (ICAP) in 1976 and ICAP II in 1980. The ICAP II upgrade provided the EA-6B with the capability of firing Shrike missiles and AGM-88 HARM missiles.
Advanced Capability EA-6B
The Advanced Capability EA-6B Prowler (ADVCAP) was a development program initiated to improve the flying qualities of the EA-6B and to upgrade the avionics and electronic-warfare systems. The intention was to modify all EA-6Bs into the ADVCAP configuration, but the program was removed from the Fiscal Year 1995 budget due to financial pressure from competing Department of Defense acquisition programs.
The ADVCAP development program was initiated in the late 1980s and was broken into three distinct phases: Full-scale Development (FSD), Vehicle Enhancement Program (VEP), and Avionics Improvement Program. FSD served primarily to evaluate the new AN/ALQ-149 Electronic Warfare System. The program used a slightly modified EA-6B to house the new system.
The VEP added numerous changes to the aircraft to address deficiencies with the original EA-6B flying qualities, particularly lateral-directional problems that hampered recovery from out-of-control flight. Bureau Number 158542 was used. Changes included: Leading-edge strakes (to improve directional stability) Fin pod extension (to improve directional stability) Ailerons (to improve slow speed lateral control) Recontoured leading-edge slats and trailing-edge flaps (to compensate for an increase in gross weight) Two additional wing stations on the outer wing panel (for jamming pods only) New J52-P-409 engines (increased thrust by 2,000 lbf (8.9 kN) per engine) New digital standard automatic flight-control system The added modifications increased the aircraft gross weight about and shifted the center of gravity (CG) 3% MAC aft of the baseline EA-6B. In previous models, when operating at sustained high angles of attack, fuel migration would cause additional shifts in CG with the result that the aircraft had slightly negative longitudinal static stability. Results of flight tests of the new configuration showed greatly improved flying qualities and the rearward shift of the CG had minimal impact.
The AIP prototype (bureau number 158547) represented the final ADVCAP configuration, incorporating all of the FSD and VEP modifications plus a completely new avionics suite, which added multifunction displays to all crew positions, a head-up display for the pilot, and dual global positioning/inertial navigation systems. The initial joint test phase between the contractor and the USN test pilots were completed successfully with few deficiencies.
After the program was canceled, the three experimental Prowlers, BuNo 156482, 158542, and 158547, were mothballed until 1999. Over the next several years, the three aircraft were dismantled and reassembled to create a single aircraft, b/n 158542, which the USN dubbed "FrankenProwler". It was returned to active service on 23 March 2005.
Improved Capability (ICAP) III Northrop Grumman received contracts from the USN to deliver new electronic countermeasures gear to Prowler squadrons; the heart of each ICAP III set consists of the ALQ-218 receiver and new software that provides more precise selective-reactive radar jamming and deception and threat location. The ICAP III sets also are equipped with the multifunction information distribution system , which includes the Link 16 data-link system. Northrop delivered two lots and delivered two more beginning in 2010. The EA-6B Prowlers in service toward the end of their service lives were the ICAP III version, carrying the ALQ-99 tactical jamming system.
Design Designed for carrier-based and advanced-base operations, the EA-6B was a fully integrated electronic-warfare system combining long-range, all-weather capabilities with advanced electronic countermeasures. A forward equipment bay and pod-shaped fairing on the vertical fin housed the additional avionics equipment.Hansen 2006, p. 9. It was the primary electronic warfare aircraft for the USN and USMC. The EA-6B's primary mission was to support ground-attack strikes by disrupting enemy electromagnetic activity.Sweetman 2002, pp. 7-8. As a secondary mission, it could also gather tactical electronic intelligence within a combat zone, and another secondary mission was attacking enemy radar sites with antiradiation missiles.
The Prowler was operated by a crew of four, a pilot and three electronic countermeasures officers (ECMOs). The two ECMOs in the rear cockpit operated the Prowler's primary jamming equipment, while the ECMO in the right front seat handled navigation, communications, and defensive electronic countermeasures. Powered by two non-afterburning Pratt & Whitney J52-P-408A turbojet engines, it was capable of speeds above , with a range over .Hansen 2006, pp. 10-11.
Design particulars included the refueling probe being asymmetrical, appearing bent to the right to improve pilot visibility over that of the A-6 Intruder.Hansen 2006, pp. 24-25. It contained an antenna near its root. The canopy had a shading of gold to protect the crew against the radio emissions that the electronic-warfare equipment produces.Hansen 2006, pp. 18-19.
Operational history 20th century
In September 1970, the EA-6B entered service with Fleet Replacement Squadron VAQ-129; 10 months later, Tactical Electronic Warfare Squadron 132 (VAQ-132) became the first operational squadron to be equipped with the type; during June 1972, VAQ-132 began its first combat deployment to Vietnam on ; it was promptly followed by VAQ-131 on and VAQ-134 on .Bowers 1990, p. 274. Two squadrons of Prowlers flew 720 sorties during the Vietnam War in support of USN attack aircraft, as well as the Boeing B-52 Stratofortress bombers of the United States Air Force; typically, they suppressed enemy air defenses just prior to the attack/bomber aircraft deploying their own payloads.
During the 1983 invasion of Grenada, four Prowlers supported the operation from .Grossnick 1997, p. 737. Two years later, in response to the Achille Lauro hijacking, Prowlers from provided ESM support during the interception of the EgyptAir 737 carrying four of the hijackers on 10 October 1985.Laur 1998, pp. 63-65.
Prowlers jammed Libyan radar and air defenses during Operation El Dorado Canyon in April 1986. Similarly, Prowlers from VAQ-135 on jammed Iranian ground control intercept radars, surface-to-air missile-guidance radars, and communication systems during Operation Praying Mantis on 18 April 1988.