The Douglas A-3 Skywarrior was designed as a strategic bomber for the United States Navy, but its primary function for much of its later service life was as an electronic warfare platform, tactical air reconnaissance platform, and high capacity aerial refueling tanker. In these roles it was among the longest serving carrier-based aircraft in history, entering service in the mid-1950s and retired in 1991. Throughout its service, it was the heaviest operational aircraft to operate from aircraft carriers, earning its nickname, "The Whale.” Eight RA-3Bs converted as electronic aggressor aircraft (primarily for war-at sea exercises) with ECM in new extended tail cone, ventral "canoe" fairing, cylindrical fairing atop vertical fin, and two detachable ram-air turbine powered ALQ-76 countermeasures pods (one under each wing). Added chaff (radar countermeasure) dispensers (streaming chaff from the tail cone and two self-protection chaff dispensers on the aft fuselage) and four ram-air turbines (two per side) to power the equipment located in the former bomb bay. Crew increased to four: pilot, navigator, crew chief, and Electronic Countermeasures Officer (ECMO) with one generally unused "jumpseat" in the aft crew compartment (formerly the weapon bay). There was no equipment position for a second Electronic Countermeasures Officer or enlisted crewman in the converted weapon bay. The "jump seat" was used for qualified instructor ECMOs training new ECMOs, for guest observers on operational flights, or for passengers during operational deployment transits. While the ERA-3B could withstand the stresses of a cable arrested landing, the ALT-40 and ALR-75 equipment in the former bomb bay was not stressed to withstand a catapult launch and the ERA-3B was never deployed aboard carriers.