The Wessex HAS.3 was a more powerful development of the Wessex HAS.1. The majority of Wessex HAS.3's were produced by converting 42 HAS.1 airframes, though an additional 3 were built new as pre-production aircraft. It was powered by a 1,600shp Napier Gazelle 18 Mk.165 turboshaft engine and equipped with the Ekco EK10 lightweight search radar, the Marconi Doppler navigation system and a duplex Newmark/Westland Mk.30 Automatic Flight Control System. This allowed it to perform adequately in the Anti-Submarine Warfare (ASW) role with automatic control of take-off, hover and transition both by day and night without having to depend on the ships radar. During it's service life from Aug 1967, the HAS.3 equipped five operational squadrons (706, 814, 819, 820 & 826Sqn's) and two training units (700 & 737Sqn). In it's ASW role, it embarked in the carriers HMS Eagle, Victorious and Hermes. Some helicopters were deployed onto County Class frigates parented by 737Sqn e.g. HMS Hampshire, Glamorgan and Antrim. After withdrawal from font-line service in 1971, HAS.3's provided the platform for the training of observers and crewmen. 737Sqn at Portland was the last unit to operate the type, disbanding in February 1983.