Editing Grumman A-6 Intruder (section)

==Variants==
{{More citations needed section|date=August 2011}}

===YA-6A and A-6A===
[[File:A-6As VMA(AW)-242 1975.jpeg|thumb|left|A-6A of VMA (AW)-242 in 1975]]

The eight prototypes and pre-production Intruder aircraft were sometimes referred to with the ''YA-6A'' designation.<ref name=Jenkins_p100>Jenkins 2002, p. 100.</ref> These were used in the development and testing of the A-6A Intruder.

The initial version of the Intruder was built around the complex and advanced ''DIANE'' (Digital Integrated Attack/Navigation Equipment) suite, intended to provide a high degree of bombing accuracy even at night and in poor weather. DIANE consisted of multiple [[radar]] systems: the [[Norden Systems]] [[AN/APQ-92]] search radar replacing the YA-6A's AN/APQ-88, and a separate AN/APG-46 for tracking, the AN/APN-141 radar altimeter, and an AN/APN-122 [[Doppler radar|Doppler navigational radar]] to provide position updates to the Litton AN/ASN-31 [[inertial navigation system]]. An air-data computer and the AN/ASQ-61 ballistics computer integrated the radar information for the bombardier/navigator in the right-hand seat. [[TACAN]] and [[Automatic Direction Finder|ADF]] systems were also provided for navigation. When it worked, DIANE was perhaps the most capable navigation/attack system of its era, giving the Intruder the ability to fly and fight in even very poor conditions (particularly important over [[Vietnam]] and [[Thailand]] during the [[Vietnam War]]). It suffered numerous teething problems, and it was several years before its reliability was established.

[[File:A-6B Intruder of VA-75 aboard USS Saratoga (CVA-60) in 1971.jpg|thumb|A-6B on the {{USS|Saratoga|CV-60|6}} in 1971]]
Total A-6A production was 480, excluding the prototype and pre-production aircraft.<ref name=Jenkins_p100/> A total of 47 A-6As were converted to other variants.<ref name=Jenkins_p100/>

===A-6B===
To provide U.S. Navy squadrons with a [[Suppression of Enemy Air Defenses|defense suppression]] aircraft to attack enemy anti-aircraft defense and SAM systems, a mission dubbed "[[Operation Iron Hand|Iron Hand]]" by the U.S. Navy, 19 A-6As were converted to ''A-6B'' version during 1967 to 1970.<ref name=Jenkins_p33>Jenkins 2002, pp. 33–41.</ref> The A-6B had many of its standard attack systems removed in favor of specialized equipment to detect and track enemy radar sites and to guide [[AGM-45 Shrike]] and [[AGM-78 Standard]] [[anti-radiation missile]]s, with AN/APQ-103 radar replacing earlier AN/APQ-92 used in the A-6A, plus AN/APN-153 navigational radar replacing earlier AN/APN-122, again used in the A-6A.

Between 1968 and 1977, several Intruder squadrons operated A-6Bs alongside their regular A-6As. Five were lost to all causes, and the surviving aircraft were later converted to ''A-6E'' standard in the late 1970s.

===A-6C===
[[File:A-6C VA-35 CVA-66 1972.jpg|thumb|A-6C of VA-35 ''Black Panthers'']]

12 A-6As were converted in 1970 to ''A-6C'' standard for night attack missions against the [[Ho Chi Minh trail]] in Vietnam. They were fitted with a "Trails/Roads Interdiction Multi-sensor" (TRIM) pod in the fuselage for [[FLIR]] and low-light TV cameras, as well as a "Black Crow" engine ignition detection system. Radars were also upgraded, with the AN/APQ-112 replacing the earlier AN/APQ-103, and an AN/APN-186 navigational radar replacing the earlier AN/APN-153. A vastly improved [[Sperry Corporation]] AN/APQ-127 radar replaced the AN/APG-46 fire control radar. One of these aircraft was lost in combat; the others were later refitted to A-6E standard after the war.

===KA-6D===
[[File:KA-6 F-14 DN-ST-87-10386.jpg|thumb|left|A KA-6D refueling an F-14A in 1987]]

To replace both the KA-3B and EA-3B Skywarrior during the early 1970s, 78 A-6As and 12 A-6Es were converted for use as [[Tanker (aircraft)|tanker]] aircraft, providing [[aerial refueling]] support to other strike aircraft. The DIANE system was removed and an internal refueling system was added, sometimes supplemented by a D-704 refueling pod on the centerline pylon. The KA-6D theoretically could be used in the day/visual bombing role, but it apparently never was, with the standard load-out being four fuel tanks. Because it was based on a tactical aircraft platform, the KA-6D provided a capability for mission tanking, the ability to keep up with strike aircraft and refuel them in the course of a mission. A few KA-6Ds went to sea with each Intruder squadron.  Their operation was integrated into the Intruder squadrons, as A-6 crew were trained to operate both aircraft and the NATOPS covered both the A6 and KA-6D. These aircraft were always in short supply, and frequently were "cross decked" from a returning carrier to an outgoing one. Many KA-6 airframes had severe G restrictions, as well as fuselage stretching due to almost continual use and high number of catapults and traps. The retirement of the aircraft left a gap in US Navy and Marine Corps refueling tanker capability. At least 16 KA-6Ds served in the [[Gulf War]].<ref>{{Cite web |date=1993 |title=Gulf War - Air Power Survey, Volume V |url=https://media.defense.gov/2010/Sep/27/2001329816/-1/-1/0/gulf_war_air_power_survey-vol5.pdf |archive-url=https://web.archive.org/web/20220627021558/https://media.defense.gov/2010/Sep/27/2001329816/-1/-1/0/gulf_war_air_power_survey-vol5.pdf |url-status=dead |archive-date=27 June 2022 |access-date=13 September 2024 |website=U.S. Department of Defense}}</ref> The Navy [[Lockheed S-3 Viking]] filled that gap until the new F/A-18E/F Super Hornet became operational.

===A-6E===
[[File:A-6E Intruder over Spain in Operation Matador.jpg|thumb|An A-6E 'SWIP' Intruder of VA-34 flying over Spain during Exercise Matador.]]

The definitive attack version of the Intruder with vastly upgraded navigation and attack systems, introduced in 1970 and first deployed on 9 December 1971. The earlier separate search and track (fire control) radars of the A-6A/B/C were replaced by a single Norden AN/APQ-148 multi-mode radar, and onboard computers with a more sophisticated (and generally more reliable) IC based system, as opposed to the A-6A's DIANE discrete transistor-based technology. A new AN/ASN-92 inertial navigation system was added, along with the CAINS (Carrier Aircraft Inertial Navigation System), for greater navigation accuracy.

[[File:Last VA-34 A-6E Intruder launch from USS George Washington (CVN-73) on 22 July 1996 (6526829).jpg|thumb|left|Final VA-34 A-6E SWIP Intruder launch from the flight deck of {{USS|George Washington|CVN-73|6}}, 1996.]]
Beginning in 1979, all A-6Es were fitted with the [[AN/AAS-33]] DRS (Detecting and Ranging Set), part of the 'Target Recognition and Attack Multi-Sensor' (TRAM) system, a small, gyroscopically stabilized turret, mounted under the nose of the aircraft, containing a [[forward-looking infra-red]] (FLIR) boresighted with a [[laser]] spot-tracker/designator and [[IBM]] [[IBM System/4 Pi|AN/ASQ-155]] computer. TRAM was matched with a new Norden AN/APQ-156 radar. The BN could use both TRAM imagery and radar data for extremely accurate attacks, or use the TRAM sensors alone to attack without using the Intruder's radar (which might warn the target). TRAM also allowed the Intruder to autonomously designate and drop [[laser-guided bomb]]s. In addition, the Intruder used an Airborne [[moving target indicator|Moving Target Indicator]] (AMTI), which allowed the aircraft to track a moving target (such as a tank or truck) and drop ordnance on it even though the target was moving. Also, the computer system allowed the use of Offset Aim Point (OAP), giving the crew the ability to drop on a target unseen on radar by noting coordinates of a known target nearby and entering the offset range and bearing to the unseen target.

In the 1980s, the A-6E TRAM aircraft were converted to the A-6E 'Weapons Control System Improvement' (WCSI) version to extend weapons capability. This added the ability to carry and target some of the first generation precision guided weapons, like the [[AGM-84 Harpoon]] missile, and [[AGM-123 Skipper]]. WCSI equipped aircraft were eventually modified to have a limited capability to use the [[AGM-84E SLAM]] standoff land attack missile. Since the Harpoon and SLAM missiles had common communication interfaces, WCSI aircraft could carry and fire SLAM missiles, but needed a nearby A-6E SWIP to guide them to target.

[[File:AN-APQ-148 Radar, Norden, 1972 - National Electronics Museum - DSC00068.JPG|thumb|upright|Norden [[AN/APQ-148]] Radar<ref>{{cite web |url=http://www.designation-systems.net/usmilav/jetds/an-apq.html |title=AN/APQ – Airborne Multipurpose/Special Radars |author=<!--Staff writer(s); no by-line.--> |date=2007-07-01 |website=designation-systems.net|access-date=2015-01-27}}</ref>]]
In the early 1990s, some surviving A-6Es were upgraded under SWIP (Systems/Weapons Improvement Program) to enable them to use the latest precision-guided munitions, including [[AGM-65 Maverick]]s, AGM-84E SLAMs, [[AGM-62 Walleye]]s and the [[AGM-88 HARM]] [[anti-radiation missile]] as well as additional capability with the AGM-84 Harpoon. A co-processor was added to the AN/ASQ-155 computer system to implement the needed MIL-STD-1553 digital interfaces to the pylons, as well as an additional control panel. After a series of wing-fatigue problems, about 85% of the fleet was fitted with new graphite/epoxy/titanium/aluminum composite wings. The new wings proved to be a mixed blessing, as a composite wing is stiffer and transmits more force to the fuselage, accelerating fatigue in the fuselage. In 1990, the decision was made to terminate production of the A-6. Through the 1970s and 1980s, the A-6 had been in low-rate production of four or five new aircraft a year, enough to replace mostly accidental losses. The final production order was for 20 aircraft of the SWIP configuration with composite wings, delivered in 1993.

A-6E models totaled 445 aircraft, about 240 of which were converted from earlier A-6A/B/C models.

===A-6F and A-6G===
[[File:A-6F 1987 DN-SC-88-00704.JPEG|thumb|A-6F prototype in 1987]]

An advanced ''A-6F Intruder II'' was proposed in the mid-1980s that would have replaced the Intruder's elderly [[Pratt & Whitney J52]] [[turbojet]]s with non-afterburning versions of the [[General Electric F404]] [[turbofan]] used in the F/A-18 Hornet, providing substantial improvements in both power and fuel economy. The A-6F would have had totally new [[avionics]], including a Norden [[AN/APQ-173]] [[synthetic aperture radar]] and multi-function cockpit displays – the APQ-173 would have given the Intruder air-to-air capacity with provision for the [[AIM-120 AMRAAM]]. Two additional wing pylons were added, for a total of seven stations.

Although five development aircraft were built, the U.S. Navy ultimately chose not to authorize the A-6F, preferring to concentrate on the [[A-12 Avenger II]]. This left the service in a quandary when the A-12 was canceled in 1991.

Grumman proposed a cheaper alternative in the ''A-6G'', which had most of the A-6F's advanced electronics, but retained the existing engines.<ref>{{citation|title=Pentagon Proposes Buying A-6 Intruders|url=http://www.grummanretireeclub.org/wp-content/themes/grumman-child/archive-newsletters/grumman-world-1988-05-13-Volume-7-Number-9.pdf|access-date=6 October 2017|periodical=Grumman World|volume=7|issue=9|page=1|date=13 May 1988}}</ref> This, too, was canceled.

===Electronic warfare versions===
{{main|Northrop Grumman EA-6B Prowler}}
[[File:Grumman EA-6A 156983 VMCJ-2 America 30.09.74 edited-2.jpg|thumb|right|US Marine Corps EA-6A Intruder electronics aircraft of VMCJ-2 ''Playboys'' aboard USS ''America'' in 1974 during a visit to [[Scotland]].]]

An [[electronic warfare]] (EW)/[[Electronic countermeasures]] (ECW) version of the Intruder was developed early in the aircraft's life for the [[United States Marine Corps|USMC]], which needed a new ECM platform to replace its elderly [[Douglas F3D Skyknight|F3D-2Q Skyknights]]. An EW version of the Intruder, initially designated ''A2F-1H'' (rather than A2F-1Q, as "Q" was being split to relegate it to passive electronic warfare and "H" to active) and subsequently redesignated ''EA-6A'', first flew on 26 April 1963. It had a [[Bunker Ramo Corporation|Bunker-Ramo]] AN/ALQ-86 ECM suite, with most electronics contained on the walnut-shaped pod atop the vertical fin. They were equipped with AN/APQ-129 fire control radar, and theoretically capable of firing the [[AGM-45 Shrike]] [[anti-radiation missile]], although they were apparently not used in that role. The navigational radar is AN/APN-153.

Only 28 EA-6As were built (two prototypes, 15 new-build, and 11 conversions from A-6As), serving with U.S. Marine Corps squadrons in [[Vietnam War|Vietnam]]. It was phased out of front line service in the mid-1970s, remaining in use in reserve VMCJ units with the USMC and then the United States Navy in specialized VAQ units, primarily for training purposes. The last EA-6A had been retired by 1993.

A much more highly specialized derivative of the Intruder was the [[Northrop Grumman EA-6B Prowler|EA-6B Prowler]], having a "stretched" airframe with two additional systems operators, and more comprehensive systems for the electronic warfare and [[SEAD]] roles. A derivative of AN/APQ-156, AN/APS-130 was installed as the main radar for EA-6B. The navigational radar was upgraded to AN/APS-133 from the AN/APN-153 on EA-6A. In total, 170 were produced. The EA-6B took on the duties of the U.S. Air Force [[General Dynamics–Grumman EF-111A Raven|EF-111 Raven]] when the DoD decided to let the U.S. Navy handle all electronic warfare missions. The Prowler has been replaced by the [[Boeing EA-18G Growler|EA-18G Growler]] in the U.S. Navy and was retired from USMC service in 2019.

===Variant list===
;YA2F-1
:Pre-production aircraft, eight built with the first four with rotating jet exhaust pipes, redesignated YA-6A in 1962.<ref name="andrade">Andrade 1979, pp. 37–38.</ref>
;A2F-1
:First production variant with fixed tailpipe, 484 built, redesignated ''A-6A'' in 1962.<ref name="andrade" />
;YA2F-1H
:Prototype electronic warfare variant, one modified from A2F-1, redesignated ''YEA-6A'' in 1962.<ref name="andrade" />
;A2F-1H
:Electronic warfare variant of the A2F-1 redesignated ''EA-6A'' in 1962<ref name="andrade" />
;YA-6A
:Pre-production aircraft redesignated from YA2F-1 in 1962.<ref name="andrade" />
;A-6A
:First production variant redesignated from A2F-1 in 1962.<ref name="andrade" />
;YEA-6A
:One YA2F-1H electronic warfare variant prototype redesignated in 1962.<ref name="andrade" />
;EA-6A
:Electronic warfare variant redesignated from A2F-1H, had a redesigned fin and rudder and addition of an ECM radome, able to carry underwing ECM pods, three YA-6A and four A-6As converted and 21 built.<ref name="andrade" />
;NA-6A
:The redesignation of three YA-6As and three A-6As. The six aircraft were modified for special tests.<ref name="andrade" />
;NEA-6A
:One EA-6A aircraft was modified for special test purposes.<ref name="andrade" />
;TA-6A
:Proposed trainer variant with three-seat, not built.<ref name="andrade" />
;A-6B
:Variant fitted with avionics for the suppression of enemy air defenses (SEAD), 19 conversions from A-6A.<ref name="Andrews"/>
;[[Grumman EA-6B Prowler|EA-6B Prowler]]
:Electronic warfare variant of the A-6A with longer fuselage for four crew.<ref name="andrade" />
;YEA-6B
:The designation of two EA-6B prototypes, which were modified for special test purposes.
;A-6C
:A-6A conversion for low-level attack role with electro-optical sensors, twelve converted.<ref name="andrade" />
;KA-6D
:A-6A conversion for flight-refueling, 58 converted.<ref name="andrade" />
[[File:Grumman A-6E Intruder of VA-52 in flight, in 1981 (6379373).jpg|thumb|A-6E Intruder of VA-52, 1981]]
;A-6E
:A-6A with improved electronics.<ref name="andrade" />
;A-6E TRAM
:A-6E upgraded with the AN/AAS-33 Target Recognition Attack Multi-Sensor or "TRAM" pod. Capable of dropping Laser Guided Bombs without a targeting pod. Can also carry the [[Harpoon (missile)|AGM-84 Harpoon]].<ref name=":0">{{Cite book|last=Morgan|first=Rick|title=Osprey Combat Aircraft 121: A-6 Intruder Units 1974-96|publisher=Osprey Publishing|year=2017|isbn=978-1-4728-1877-5}}</ref>
;A-6E SWIP
:A-6E TRAM upgraded with the [[AN/ALR-67 radar warning receiver|AN/ALR-67 RWR]] and ability to carry the [[AGM-88 HARM]], [[AGM-62 Walleye]], [[AGM-84E Standoff Land Attack Missile|AGM-84E SLAM]] and [[AGM-65 Maverick]]. Several versions had new composite wings.<ref name=":0" />
;A-6F Intruder II
:Advanced version with updated electronics and [[General Electric F404]] turbofans; only 5 built.
;A-6G
:Proposed cheaper alternative to the A-6F, with its advanced electronics, but existing J52 turbojets.
;G-128-12
:Unbuilt single-seat A-6 based design proposal for the VA(L) competition for [[A-4 Skyhawk]] replacement based on existing design. Contract ultimately awarded to the [[LTV A-7 Corsair II]].<ref name="Buttler">Buttler 2010, pp. 147–148.</ref>