The early A-3 variants had a crew of three: pilot, bombardier/navigator (BN) and crewman/navigator (aka: third crewman). An unusual cockpit configuration was incorporated with the three crew sitting under a framed canopy. In the raised compartment, the pilot and bombardier/navigator sat in a side-by-side arrangement with the pilot's station on the port side having full flight controls. On initial variants, a third crew member, who also acted as a gunner for the twin tail-mounted 20mm cannon that briefly equipped the original bomber version of the A3D/A-3A (removed and replaced by ECM equipment), sat behind the pilot in an aft-facing seat. The third crewman station had the sextant for celestial navigation and the defensive electronic counter measures equipment. Later electronic reconnaissance variants could accommodate a crew of seven with the flight crew consisting of a pilot, co-pilot and navigator plus four electronic systems operators occupying stations in the former bomb bay in the spacious fuselage.