The Sea Vixen's main role was that of defending the fleet at sea. Known as an All Weather Fighter (AWF), it had a radar, the Air Intercept18 (AI 18) with an A (Azimuth) scope and B (Elevation) scope. This was the reason why the Observer was enclosed in a dark enclosed space. His small window even had a blackout curtain.
The Sea Vixen had two types of missiles.The first was a Firestreak, an Infra Red homing missile. Only Mark 1 Sea Vixens were fitted with this weapons system. The second missile type was a Red Top radar guided missile. The Mark 2 Sea Vixens were dual fitted with Firestreak and Red Top missiles. This was the reason for the airframe changes from Mk 1 Sea Vixen to Mk2 version. The airframe changes were a forward extension of the twin tail booms on the upper surface of the wings. These contained the Red Top missile computers. The forward protrusions of these booms were fitted with extra fuel tanks called Pinion Tanks.
Interceptions were constantly practiced at High, Medium, and Low Level from 45,000 feet to 500 feet over the sea by day and by night. The name AWF was derived from the fact that these interceptions could be achieved without visual contact, the pilot flying blind on instruments. This was state of the art for this period in aviation. For different heights there were different radii of turn to be assessed.
Very close crew cooperation and team work were required within the Sea Vixen Crew. The Vixen would be vectored to a target by either the Aircraft Carrier or a ship in company under radar control of a Direction Officer, or by a Gannet Airborne Early Warning (AEW) aircraft on patrol. On target pickup the Observer would take control of the intercept. He would bark out snappy orders for the pilot to follow in order to achieve a missile kill position +/- 30° or so astern of the target and within the range of the missile.