A-6 Intruder US NAVY
More reading: EA-6 Prowler
The A-6 was the U.S. Navy's all-weather long-range attack aircraft with the ability to operate day or night. It was a subsonic, two seat aircraft fitted with the ability to carry up to 15,000 lb or numerous types of munitions. L
ater A-6E's were fitted with the Target Recognition and Attack Multisensor (TRAM), which included Forward Looking Infra-Red (FLIR) for precision-guided munitions. Over 660 A-6 aircraft were built.
In December 1957, the Grumman corporation was selected by the US Navy to fulfill the new long-range low-level tactical strike aircraft requirement with their A-6 Intruder.
Northrop Grumman Corporation (NYSE: NOC) is an American global aerospace and defense technology company formed by the 1994 purchase of Grumman by Northrop. The company was the fourth-largest defense contractor in the world as of 2010, and the largest builder of naval vessels. Northrop Grumman employs over 122,000 people worldwide. Its 2007 annual revenue is reported at US$32 billion. Northrop Grumman ranks #61 on the 2010 Fortune 500 list of U.S. industrial companies. It is headquartered in the Century City area of Los Angeles, California.
The A-6A's first flight occurred on April 19, 1960, and the first of 482 production aircraft were delivered in February 1963. The A-6A introduced the new Digital Integrated Attack Navigation Equipment (DIANE), which proved to be excellent in all weather conditions. In all, 19 A-6B's were converted from A-6A standard for SAM suppression, and 12 A-6C's were converted with FLIR and LLLTV equipment for improved night-attack capabilities. The upgraded A-6E first flew on February 27, 1970 and introduced a multi-mode navigation/attack radar system. The A-6 was later replaced by the F/A-18 Hornet.
The A-6E is an all-weather, two-seat, subsonic, carrier-based attack aircraft. In spite of its weight, it has excellent slow-flying capabilities with full span slats and flaps. The crew, sitting side by side, can see in all directions through a broad canopy. The aircraft is equipped with a micro-miniaturized digital computer, a solid state weapons release system, and a single integrated track and search radar. The Intruder is armed with laser-guided weapons and equipped with a chin turret containing a forward-looking infra-red (FLIR) system and laser designator and receiver.
The A-6 worked around the clock in Vietnam, conducting attacks on the targets with a pinpoint accuracy unavailable through any other aircraft at that time.The A-6E proved once again that it is the best all-weather precision bomber in the world in the joint strike on Libyan terrorist-related targets in 1986. Navy A-6E Intruders and Air Force FB-111s penetrated the sophisticated Libyan air defense systems, which had been alerted by the high level of diplomatic tension and by rumors of impending attacks. Evading more than 100 guided missiles, the strike force flew at low levels in complete darkness and hit its target. A-6 aircraft were used extensively during Operation Desert Storm, providing precision bombing on a wide range of targets. The night and all-weather attack capabilities enabled the A-6 to neutralize anti-aircraft batteries and attack well-protected tactical targets with minimum casualties. The precision munitions used by the A-6 provided exact targeting of targets in a complex environment.
AGM-45 Shrike(left) is an American anti-radiation missile designed to home in on hostile antiaircraft radars. The Shrike was developed by the Naval Weapons Center at China Lake in 1963 by mating a seeker head to the rocket body of an AIM-7 Sparrow. It was phased out by U.S. in 1992 and at an unknown time by the Israeli Air Force (the only other major user), and has been superseded by the AGM-88 HARM missile. The Israel Defense Forces developed a version of the Shrike that could be ground-launched and mounted it on an M4 Sherman chassis as the Kilshon (Hebrew for Trident).
This designation was given to eight prototypes and pre-production aircraft, used in the development of the A-6A Intruder, equipped with AN/APQ-88 radar.
The initial version of the Intruder was built around the complex and advanced DIANE (Digital Integrated Attack/Navigation Equipment), 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 AN/APQ-88 on YA-6A, and a separate AN/APG-46 for tracking, AN/APN-141 radar altimeter, and AN/APN-122 Doppler navigational radar to provide position updates to the AN/ASN-31 inertial navigation system. An air-data computer and ballistics computer integrated the radar information for the bombardier/navigator (BN) in the right-hand seat. TACAN and ADF were also provided for navigational use. When it worked, DIANE was perhaps the most capable nav/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, though, and it was several years before its reliability was established.
Total A-6A production was 488, including six pre-production prototypes. Many of the surviving aircraft were converted to other variants.
To provide Navy squadrons with a defense suppression aircraft to attack enemy antiaircraft defense and SAM missile systems, a mission dubbed "Iron Hand" in Navy parlance, 19 A-6As were converted to A-6B standard from 1967 to 1970. The A-6B had many of its standard attack systems removed in favor of special equipment to detect and track enemy radar sites and to guide AGM-45 Shrike and AGM-78 Standard anti-radiation missiles, with AN/APQ-103 radar replaced earlier AN/APQ-92 in A-6A and AN/APN-153 navigational radar replaced earlier AN/APN-122 in A-6A. Five were lost in combat, and the rest were later converted to A-6E standard in the late 1970s.
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 AN/APQ-112 replacing earlier AN/APQ-103 in A-6B, and AN/APN-186 navigational radar replacing earlier AN/APN-153 in earlier A-6B. A vastly improved Sperry Corporation AN/APQ-127 radar replaced earlier AN/APG-46 fire control radar in A-6A/B. One of these aircraft was lost in combat, the others were later converted to A-6E standard after the war.
In the early 1970s 78 A-6As and 12 A-6Es were converted for use as 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 packages and refuel them in the course of a mission. A few KA-6Ds went to sea with each Intruder squadron, and the retirement of the aircraft left a gap in USN and USMC refueling tanker capability. The USN S-3 Viking also has an aerial refueling capability, but its performance and fuel capacity effectively limit it to the role of recovery tanker. The loss of mission tanking capability was only later remedied by the new F/A-18E/F Super Hornet, which can act as a mission tanker.
The definitive attack version of the Intruder, introduced in 1970, with its first deployment, 9 December 1971, with vastly upgraded navigation and attack systems. 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 the 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 Intertial Navigation System), for greater navigation accuracy.
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 FLIR boresighted with a laser spot-tracker/designator and IBM System/4 Pi 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 bombs. In addition, the Intruder used AMTI (Airborne Moving Target Indicator) which allowed the aircraft to track a moving target (such as a tank or truck) and drop ordnance on him 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 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 Mavericks, AGM-84 Harpoons, AGM-84E SLAMs, AGM-62 Walleyes and the AGM-88 HARM anti-radiation missile. After a series of wing-fatigue problems, about 85% of the fleet was fitted with new graphite/epoxy/titanium/aluminum composite wings.
An advanced A-6F Intruder II was proposed in the mid-1980s that would have replaced the Intruder's elderly Pratt & Whitney J52 turbojets 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 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 cancelled 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. This, too, was cancelled.
Electronic warfare versions
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