The Navy's experience in the Korean War showed the need for a new long-range strike aircraft with high subsonic performance at very low altitude--an aircraft that could penetrate enemy defenses and find and destroy small targets in any weather. The Grumman A-6 Intruder was designed with these needs in mind. The Intruder first flew in 1960 and was delivered to the Navy in 1963 and the Marine Corps in 1964.
The Navy accepted this airplane as an "A" model in 1968. It served under harsh combat conditions in the skies over Vietnam and is a veteran of the 1991 Desert Storm campaign, when it flew missions during the first 72 hours of the war. It has accumulated more than 7,500 flying hours, over 6,500 landings, 767 arrested landings, and 712 catapult launches.
The origins of what became the A-6 Intruder came in a 1957 Navy specification for a new attack airplane to replace the aging Douglas AD/A-1 Skyraider. The Marine Corps initiated the request with a desire for a Close Air Support aircraft capable of short takeoff. At the same time, the Navy's experience in the Korean War showed the need for a new long-range strike aircraft with a high subsonic performance at tree-top height to permit under-the-radar penetration of enemy defenses and to be capable of finding and hitting small and moving targets in any weather. The final specification combined both of these missions, giving requirements for speed, range, weight, and payload, but left the number and type of engines to the bidders. The specifications also included a new wrinkle: unlike prior invitations, this one required that the bidders also design and integrate the entire weapons system, rather than having another manufacturer supply the equipment for later installation.
Grumman’s design won out. Designated the A2F Intruder (re-designated A-6 in 1962), it featured twin jet engines in the wing roots, and side-by-side seating for the two-person aircrew, with the Bombardier/Navigator’s seat slightly lower and further back to improve the pilot’s view out the right side of the aircraft. The seating arrangement was possible because of the bulbous nose, necessary to house the large target acquisition and tracking radar and a separate, smaller terrain radar. Input from these and other instruments fed into a central computer system, the Digital Integrated Attack and Navigation Equipment (DIANE), which drove new Cathode Ray Tube (CRT) displays – one of the first times these were used in an aircraft – to guide the pilot in navigation and bombing. The DIANE system was critical to the Intruder’s all-weather ability. The Intruder’s shape led to nicknames of “Flying Drumstick” and “Iron Tadpole” along with the more general “Double Ugly.”
Initial orders for the Intruder were placed in March 1959 for eight YA2F-1 development aircraft. The first one flew on April 19, 1960. The original design featured jet tailpipes that tilted down 23 degrees to help shorten takeoffs and landings, but testing with the YA2F-1s showed that this made no difference, so the feature was removed from production aircraft along with other changes as a result of testing. The YA2F-1s also added strengthened nose gear to accommodate the Navy’s new nose-tow catapult system that replaced the older bridle-tow system. The Intruder was the first to have the new tow bar on the nose gear after Grumman’s W2F-1/E-2A Hawkeye early warning airplane, designed about the same time as the Intruder.
The first A-6As were delivered to the Navy in 1963 and to the Marines in 1964. The first operational squadron to receive them was VA-75, which began supporting US forces in Vietnam in 1965.flying off of the carrier USS Independence. The Digital Integrated Attack and Navigation Equipment (DIANE) and its subsystems incorporated into the aircraft enabled the crew to attack preselected targets at night or under adverse weather conditions without having to look out of the cockpit during the mission (from launch to recovery). On May 23, 1966, an A-6 fitted with a hose and drogue-refueling apparatus made its first flight to demonstrate that a "tanker" version of the jet was feasible, leading to the dedicated KA-6D aerial refueller.
As A-6 aircraft were produced developments in sophisticated electronics and delivery hardware were incorporated. Nineteen A models were modified to A-6Bs for “Iron Hand” missions (suppression of enemy anti-aircraft missiles). About a dozen aircraft became C models that carried a specialized belly pod called TRIM (Trails, Roads, Interdiction Multi-sensor) that included Low Light Level TV (LLLTV), Forward Looking Infrared (FLIR), and other specialized systems. TRIM was heavy and unreliable and was replaced with a wing-mounted “Pave Knife” pod designed by the U.S. Air Force that added laser targeting and could be flown on many aircraft, not just the A-6. Properly used, Intruders were capable of delivering highly effective aerial attacks. For example, two A-6s made a night strike, dropping twenty-six 500 lb. bombs against a power plant in North Vietnam. The Vietnamese were convinced that B-52 bombers had been at work. A Navy Cross was awarded for that mission.
The final version of the Intruder, the A-6E, first flew in February 1970, in the form of a modified A-6A. 240 A-6Es were rebuilt A, B, and C models with another 207 that Grumman manufactured new. The new model, featuring an updated avionics suite, airborne radar set, and navigational computer, entered service with the VA-42 training unit in 1971, and with VA-85 as the first operational unit in December that year.
The new radar set was a multi-mode radar that replaced the two single-mode radars in the A-6A. As a result, there was space available in the nose for new sensors, but the final design of those sensors took longer. Grumman delivered most of the A-6Es (new and conversion) with accommodations to install the sensors later. These sensors ultimately became a chin-mounted pod known as TRAM – Target Recognition Attack Multisensor – that featured FLIR (Forward Looking Infra-Red camera), laser ranging and designation, and a laser sensor (so the bombardier/navigator could see targets designated by others) in a gyro-stabilized turret. The TRAM began coming into the fleet in 1979. New-construction Intruders had them installed on the production line as did older Intruders converted after that, but most were retrofitted to aircraft in the field.
After fatigue problems were discovered in the A-6E fleet, a new wing of graphite/epoxy construction was developed and flown by 1987. In addition to the new composite wing, these aircraft also were fitted with a digital armament system and a standoff weapons capability under the Systems Weapons Integration Program (SWIP).
Since Vietnam, A-6s have made effective all-weather strikes against targets in Libya during the Gulf of Sidra crisis, Iranian gun boats in the Persian Gulf, and Iraqi installations during Desert Storm operations. In fact, TRAM-equipped A-6E Intruders were responsible for 85% of the laser designations and laser-guided bomb drops during Desert Storm. The Intruder’s last combat missions were over Bosnia in 1994. The last Intruders were retired in 1997.
NASM's Intruder (BuNo 154167) began life as an A-6A. It was accepted by the U. S. Navy on March 5, 1968 at the Grumman plant on Long Island and flown to NAS Whidbey Island, Washington. It was soon assigned to Marine Attack Squadron, All-Weather (VMA(AW))-533 and deployed to the expeditionary airfield at Chu Lai, Vietnam. It flew combat missions from Chu Lai, Da Nang, and Nam Phong Air Bases for a year and a half before being sent to Norfolk for overhaul. The plane then cycled through several other Marine Attack squadrons before conversion to an A-6E at the beginning of 1975. It served with three more Marine Attack squadrons before receiving its TRAM upgrades in 1981, at which point it was delivered to a Navy Attack Squadron, VA-34. Flying off USS America (CV 66), the squadron provided close air support and surveillance for the multinational peacekeeping force sent into Beirut, Lebanon in 1982 to try to defuse tensions in the Lebanese war. The airplane was back over Beirut a year later, this time with VA-65 off USS Dwight D. Eisenhower (CVN 69). It received new wings in 1985, then returned to Marine service. It was serving with VMA(AW)-224 when, on August 23, 1990, the squadron flew from the United States to Bahrain, where it immediately began supporting forces in Operation DESERT STORM, the mission to liberate Kuwait from occupying Iraqi forces, and flew missions during the first 72 hours of that war. The squadron returned to the US in March 1991. After time in a few more squadrons, it was given one last overhaul in 1993 before being flown to Andrews Air Force Base for delivery to NASM. During its flying career, it had accumulated more than 7,500 flying hours, more than 6,800 landings (767 of which were arrested landings), and 712 catapult launches.