Aircraft of the ADF – N7 Westland Wessex

The Wessex prototype, a development of the US Sikorsky S-58 re-engined with the Gazelle turboshaft, had flown on May 17 1957. The type then entered frontline service with the Royal Navy’s 815 Squadron in July 1961.

The Wessex Mark 31, the RAN variant, was similar to the Royal Navy Wessex HAS.1, but was powered by the more powerful 1540shp (1150kW) Napier Gazelle Mark 162 (model NGa 13/2) in place of the 1450shp (1080kW) Gazelle 161.

The 27 RAN machines were delivered consecutively off the Yeovil production line, with the Westland sequence numbers WA200 to WA226. The RAN accepted the first three Australian aircraft at Westland’s Yeovil plant on August 30 1962. On October 31, the first Wessex arrived in Sydney, and was delivered to HMAS Albatross the following day. The maiden Australian flight was conducted on November 20 1962 by WA200 at Albatross, followed by an official ceremony on November 23. The first two aircraft, WA200 and WA201, were then handed over to 725 Squadron, which commenced an intensive flying schedule from January 1963.

The conversion flying conducted by 725 Squadron enabled the commissioning of the frontline unit, 817 Squadron, on July 18 1963 with 10 Wessex. On August 1, 817 Squadron embarked on board HMAS Melbourne. To commemorate becoming operational, 817 Squadron staged a ceremonial flypast on September 4 of its 10 helicopters – in true naval spirit – under the Sydney Harbour Bridge.

Typical complement of the two Wessex units was 10 aircraft with 816 and nine with 725. The remaining machines were rotated through deeper maintenance and storage.

The first eight aircraft which had been delivered to 725 Squadron had been coded 880 to 887, but this was changed in 1963, with the 27 helicopters being coded 810 to 836. All Wessexes initially retained their Westland constructor’s numbers (from WA200) as RAN serial numbers, and these have often been mistaken as Royal Navy serial numbers.

By 1965, “Confrontation” with Indonesia had reversed the earlier policy of only operating ASW helicopters from the carrier, and Grumman Trackers and Douglas Skyhawks were ordered to provide a reprieve to the Fleet Air Arm’s fixed wing elements.

In addition to being embarked on HMAS Melbourne, 817 Squadron’s Wessexes were also deployed on HMAS Sydney for anti-submarine duties during troop movement to Vietnam. During 1967, four of 725 Squadron’s Wessexes were also embarked aboard Sydney for a Vietnam deployment.

Early in 1969, 817 Squadron began operating the upgraded Wessex Mark 31B. Between 1968 and 1970, 23 Mark 31A were modified to the 31B standard. The first flight of the 31B had been in June 1968, with two aircraft modified by Westlands in England, and subsequent modifications carried out by Hawker de Havilland at Bankstown.

The improvements included incorporation of the US AN/AQS-13 sonar system for underwater detection of submarines, the higher powered 1600shp (1195kW) Napier Gazelle Mark 165 (model NGa 22) turboshaft engine, improved TACAN navigation and UHF communication systems, and a RUDAT station keeping radar. The main external distinguishing feature of the upgrade was the addition of a fairing aft of the main rotor mast.

Not all of the RAN’s Wessex fleet underwent the upgrade to Mark 31B standard, as WA206, WA207 and WA225 had all been previously written-off, and WA217 had been damaged and was held in storage. After service as an instructional airframe, WA217 was acquired by the Australian Naval Aviation Museum (ANAM), at HMAS Albatross, and remains today as the sole surviving Mark 31A.

The 31B aircraft continued in the role of anti-submarine protection for the fleet, embarked on HMAS Melbourne, until February 2 1976, when HS-817 Squadron re-equipped with the Westland Sea King Mark 50 anti-submarine helicopter. The Wessex then assumed a utility role, with its sonar equipment removed, to then equip HT-723 at Albatross.

On February 9 1984, HU-816 Squadron reformed – having previously been the first line Tracker squadron (VS-816) – with Wessex helicopters transferred from 723. 816’s 10 Wessexes supported the army with amphibious operations from HMAS Tobruk, and land-based troop carrying. In addition, 816 provided utility tasking and search and rescue (SAR) for the fleet.

The last aircraft were retired from service at the end of 1989. The type had served for 27 years with the RAN, flying with 723, 725, 816 and 817 Squadrons. Most of the RAN Wessex fleet were renumbered in the N7 series. Those below listed with the older WA serial number were written-off before having an N7 number applied.

Survivors in Australia now include N7-202 in Darwin, to commemorate the type’s assistance after Cyclone Tracy in 1974, and N7-216 at the Maritime Museum at Darling Harbour in Sydney. The Navy has retained N7-214, N7-217, N7-220, N7-221, N7-222 and N7-224 for display or storage at ANAM at Albatross.