The original A-6B designation was for a day-only version of the A-6 Intruder, with no all-weather capability. The designation A-6B may have also been intended for a single-seat version of the Intruder designed for the Navy's VAL (light attack) competition which was won by the LTV A-7 Corsair II. In the event, the designation A-6B was given to three batches of A-6As that were modified in the field as specialized defense suppression aircraft.
The first ten A-6Bs (Bu Nos 149949, 149957, and 151558/151565) were obtained by stripping off most of the attack systems, substituting them with specialized equipment that could detect radars from enemy surface-to-air missile systems. They lacked some of the more sophisticated electronic systems of later versions. They were equipped with the ability to carry AGM-78 Standard anti radiation missiles.
The next three (BuNos 155628/155630) were fitted with the passive-angle-tracking anti-radiation-missile (PAT/ARM) system. This was a system developed by the Johns Hopkins Applied Physics Laboratories to enhance the accuracy of the AGM-78A missile and to make it possible for the missile to continue to home in on enemy radars after they were turned off. The first modified aircraft (BuNo 155628) flew on August 26, 1968. These were issued to VA-85 "Black Falcons"
The last 6 (BuNos 149944, 149945, 151591, 151820, 152616, and 152617) were fitted with the Target Identification Acquisition System (TIAS), developed by IBM. these were issued to VA-34 "Blue Blasters".
The first A-6B was delivered in August of 1967, and the last in August 1970. At one time, there were plans to convert 54 A-6As into A-6Bs, but only 19 were actually converted.
It was intended that each Intruder squadron would have a couple of A-6Bs which would operate alongside the conventional A-6As. A-6Bs were issued to several squadrons--VA-34, VA-35, VA-85 and VA-95, where they operated alongside conventional A-6As. The A-6B was capable of operating alone against SAM sites, since it carried passive electronic countermeasures equipment for detecting radar emissions as well as missiles for attacking them. The usual load was two Shrike and two Standard ARMs, plus a fuel tank on the fuselage centerline. Five were lost during the Vietnam War. The 14 survivors were all upgraded to A-6E standards between December 1975 and December 1979. The last A-6B was converted t A-6E format in December of 1979.
149935/149958 Grumman A-6A Intruder 149944, 149949, 149955, 149957 modified as A-6B (4) 151558/151612 Grumman A-6A Intruder 151558/151565, 151591 modified as A-6B (9) 151780/151827 Grumman A-6A Intruder 151820 modified as A-6B (1) 152583/152646 Grumman A-6A Intruder 152616, 152617 converted to A-6B (2) 155581/155721 Grumman A-6A Intruder 155628/155630 modified as A-6B (3)