The EA-6B remains an essential element of US naval air power and has taken part in all US major actions since it entered service in 1971. Since the retirement of the USAF's EF-111A Raven in 1997, the Prowler has assumed the full responsibility for the EW mission in US service, with joint USAF/USN squadrons operating the type.
The Prowler was developed from the earlier EA-6A EW variant that saw service in Vietnam. Externally similar to the A-6 Intruder two-seat attack aircraft, the EA-6B featured a nose section extended by 1.37 m for a four-seat cockpit, and a distinctive fin pod to house the passive receivers for the ALQ-99 Tactical Jamming Systems (TJS). The Prowler's advanced ECM system is based upon the ALQ-99 TJS and up to ten noise jamming transmitters can be carried in five self-powered external jammer pods.
Delivery of production Prowlers began to the US Navy in January 1971; a total of 170 EA-6Bs was built until 1991. The jamming ability and capacity of the EA-6B has been progressively upgraded from 1973 through the introduction of the EXCAP (Expanded Capability) initiatives. From 1995, the EA-6B acqured the ability to use more direct methods to counter the threat posed by enemy SAM sites. The EA-6B can now act as a shooter with the AGM-88 HARM anti-radar missile.
To keep the Prowler serving well into the next century, the remaining airframes are beginning to undergo ICAP-III development. This is replacing the ALQ-99 with improved TJS receivers and introduces a fully integrated communications jamming system to give the EA-6B the ability to react to the latest SAMs. The Prowler currently equips 16 US Navy and four USMC squadrons; five Navy squadrons provide electronic warfare support to USAF expeditionary units. It is expected to remain in service to at least 2015.