A-6 Intruder

The Grumman A-6 Intruder is a twin-engined, all-weather subsonic attack aircraft built by Grumman Aerospace for the U.S. Navy and U.S. Marine Corps. It entered squadron service in February 1963 and served as the two services' principal medium and all-weather/night attack aircraft until 1997. It was the first U.S. Navy aircraft with an integrated airframe and weapons system, and was flown by a crew of two seated side by side.

Development

The Navy issued an Operational Requirements Document in October 1956 and a Request For Proposals in February 1957 for a carrier-based attack aircraft able to strike in any weather, replacing the piston-engined Douglas A-1 Skyraider and providing STOL performance for Marine close air support. Eight companies submitted eleven proposals; Grumman's Type G-128 was selected on 2 January 1958 and contracted as the A2F-1 the following month. The design team under Robert Nafis and Lawrence Mead, Jr. worked between Bethpage, New York, and Calverton, Riverhead. The first YA2F-1 prototype flew on 19 April 1960, the second on 28 July 1960. Testing led to the tailplane being moved 16 in (41 cm) aft, relocation of the airbrakes to the wingtips, a wider-chord rudder base, and abandonment of tilting tailpipes in favour of fixed nozzles angled seven degrees down. Total A-6A production was 480 aircraft; the A-6E totalled 445, about 240 of them conversions. The last A-6E was delivered in 1992 and production was terminated in 1990.

Design

The wing was optimised for subsonic cruise with a bomb load and was later adapted, with pivots, for the F-14 Tomcat. The pilot sat left, the bombardier/navigator right and slightly lower; the pilot had a cathode ray tube Vertical Display Indicator giving a synthetic forward view with steering cues. The A-6A used the DIANE suite: AN/APQ-92 search radar, AN/APG-46 track radar, AN/APN-141 radar altimeter, AN/APN-122 Doppler and Litton AN/ASN-31 INS. The A-6E replaced these with the single Norden AN/APQ-148, later AN/APQ-156, plus AN/ASN-92 INS and CAINS. From 1979 the AN/AAS-33 TRAM turret added FLIR and a laser designator/spot tracker with an IBM AN/ASQ-155 computer. Power came from two Pratt & Whitney J52-P8B turbojets of 9,300 lbf each. Litton-built BACE automatic diagnostic equipment supported maintenance.

Armament

Five hardpoints, four underwing and one under the fuselage, each rated at 3,600 lb, gave a total of 18,000 lb. Loads included 28 Mk 82, 13 Mk 83 or 5 Mk 84 bombs, GBU-10/12/16 laser-guided bombs, Mk 20 Rockeye II, CBU-72, Mk 60 Captor mines and Zuni or FFAR rocket pods. Guided weapons comprised AGM-45 Shrike, AGM-78 Standard ARM, AGM-62 Walleye, AGM-65 Maverick, AGM-84 Harpoon, AGM-84E SLAM, AGM-88 HARM, AGM-123 Skipper and AIM-9 Sidewinder. Up to three B43, B57 or B61 nuclear weapons could be carried, released by semi-automated toss bombing.

Operational History

Deliveries began to VA-42 in February 1963, with VA-75 as the first operational fleet squadron from October 1963. In Vietnam the Navy and Marine Corps lost 84 Intruders: 56 to ground fire and AAA, 10 to SAMs, 2 to MiGs and 16 to operational causes. The first loss was a VA-75 aircraft from USS Independence on 14 July 1965; the last was a VA-35 aircraft from USS America on 24 January 1973. Marine Intruders operated mainly from Chu Lai, Da Nang and Nam Phong, Thailand. One Intruder was downed by Syrian missiles over Lebanon on 4 December 1983. VA-34 and VA-55 took part in Operation El Dorado Canyon in April 1986. VA-145 struck Iranian oil platforms during Operation Nimble Archer on 19 October 1987, and VA-95 sank the frigate Sahand during Operation Praying Mantis on 19 April 1988. Gulf War Intruders flew over 4,700 combat sorties from six carriers and from Shaikh Isa, Bahrain, losing three aircraft. Israel requested up to 24 aircraft in 1966, but no export sale occurred. The type left Marine Corps service on 28 April 1993 and was retired on 28 February 1997.

Variants

• A-6A: Initial production version built around the DIANE navigation/attack suite, 480 built.
• A-6B: Defence suppression conversion of 19 A-6As carrying AGM-45 and AGM-78 anti-radiation missiles.
• A-6C: Twelve A-6As fitted with a TRIM pod housing FLIR and low-light TV plus a "Black Crow" ignition detector for Ho Chi Minh trail interdiction.
• KA-6D: Tanker conversion of 78 A-6As and 12 A-6Es with DIANE removed and an internal refuelling system.
• A-6E: Definitive attack version first deployed 9 December 1971, later upgraded with TRAM, WCSI and SWIP standards and composite wings.