Country of origin:

United Kingdom

Description:

Anti-submarine warfare and search-and-rescue helicopter

Power Plant:

One flat-rated 1,149 kw (1,540 shp) Napier Gazelle N.ga.113/2 turboshaft

Specifications:

Armament:

Two homing torpedoes or depth bombs

History:

The Westland Wessex was a British development of the Sikorsky S-58, with a turboshaft engine replacing the original piston-engine radial. In 1956 Westland purchased a licence to develop and produce the type, which was then in production for the US Navy as the HSS-1, an anti-submarine helicopter.  An HSS-1 airframe (c/n 58265 – BuAer 141602) was taken from the Sikorsky production line to be used as the British prototype (XL722).  It was initially flown with a 1,138 kw (1,525 hp) Wright Cyclone piston engine with B-class registration G-17-1 and was tested at Boscombe Down in Wiltshire before being grounded in August for installation of the Gazelle engine.

The airframe was fitted with an 821 kw (1,100 shp) Napier Gazelle N.Ga-11, the HSS-1 demonstrator (XL722) being flown for the first time on 17 May 1957. Extensive trials were carried out to develop the power plant installation.  The type was then put into production as the Wessex.  The first production machine built in the United Kingdom was flown on 20 June 1958.  Production aircraft were similar to the pre-production aircraft but had up-rated Gazelle engines of 1,149 kw (1,540 shp).

The Wessex was developed initially for service in the anti-submarine role, carrying one or two homing torpedoes externally, and a crew of two pilots, an observer, and a rating.  Deliveries to the Royal Navy commenced in 1960, and in 1962 an assault transport version, known as the Wessex I, was built, this being capable of carrying 15 troops internally, and having provision for a 1,814 kg (4,000 lb) externally-slung load.

Further development of the type occurred for the British armed forces, including the Wessex HC Mk 2 transport version for the RAF, which was fitted with two 1,007 kw (1,350 shp) Bristol Siddeley Gnome shaft-driven turbines coupled to a single gearbox and de-rated to a total of 1,156 kw (1,550 shp); the HAS Mk 3 with a 1,156 kw (1,550 shp) Napier Gazelle N Ga-18 Mk 165 engine and a performance improvement; and the Wessex HC Mk 5, powered with the two Gnome engines of the Mk 2, being purchased for service on board Commando arriers of the Royal Navy.

In July 1961 the RAN ordered the Wessex for anti-submarine duties aboard the aircraft carrier HMAS Melbourne, a total of 27 examples being obtained, the first (WA200) being accepted on 6 September 1962 at Westland in the UK.  It was immediately shipped to Australia and taken by road to HMAS Albatross, Nowra, NSW arriving on 11 November 1962.  After re-assembly it was test flown on 22 November and on the 29th of that month No 725 Squadron commenced operating the type.  A further three arrived in August 1962, one more later that year The other 23 were delivered during 1963.  These were similar to the HAS Mk I but were fitted with the 1,149 kw (1,540 shp) Gazelle 162 engine.  Serials were WA200 to WA226, these also being their construction numbers.

These helicopters continued in service for many years, being modified to Mk 31A standard in 1968-1969, this involving an improved sonar system, increased load carrying capacity, a more powerful engine, improved navigational aids, station keeping radar, and improved communications equipment, 23 of the aircraft being converted.  Later 22 were modified to Mk 31B standard, this including the installation of a 1,231 kw (1,650 shp) Napier Gazelle M165C turboshaft, two in the United Kingdom and the remaining 21 by Hawker de Havilland at Bankstown, NSW by the installation of up-rated engines.

At one stage in 1983 the type was grounded due to the loss of one aircraft in Bass Strait, a number of machines at that time being based at RAAF East Sale, VIC and beingconveyed from the base to HMAS Tobruk by RAAF Chinook. The type was eventually replaced by ten Westland Sea Kings in the anti-submarine role and the Wessex continued for many years thereafter in the training and utility transport role.  A number were placed in storage but, after the loss of four of the ten Sea Kings in accidents, a number of Wessex were returned to service.

A number were lost in service:  N7-218 ditched in the Java Sea after engine failure and was later recovered;  N2-212 ditched in Jervis Bay, NSW on 22 January 1978 and was recovered for the FAA Museum;  WA206 crashed near Crookhaven, NSW on 24 November 1964;  WA207 crashed at sea on 20 July 1965;  WA213 crashed in the North Sea on 13 July 1977;  WA209 crashed into the sea off Bondi Beach on 26 May 1987;  WA215 crashed into Bass Strait on 4 December 1983;  WA220 crashed near Nowra on 3 November 1985;  WA225 crashed near Jervis Bay on 6 March 1967;  and WA217, later N7-217, eventually became an Instructional Airframe.  On the occasion of 21 years of service with the RAN fourteen Wessex made a fly-past at HMAS Albatross.

In 1982, with the introduction of the Bass Strait Counter Terrorism Plan, Wessex Mk 31B helicopters of HC723 were deployed for counter-terrorism training, the whole fleet of 20 survivors being based for a period at RAAF East Sale.  These operations included practice attacks by the helicopters carrying SAS troops to the oil-rigs and operating at night.

In the 1980s, due to the importance of the production of oil in Bass Strait, the Australian Government introduced a maritime restriction zone in that area, the initial policing of the area being given to Grumman Trackers of the RAN.  Later the work was performed by Lockheed Orions of the RAAF, and then civilian Learjets on contract to the Australian Government.  Eventually the work was carried out by RNZAF Douglas A-4 Skyhawks based at HMAS Albatross.

In RAN service the Wessex was attached to HS817 Squadron on board HMAS Melbourne and HT725 at HMAS Albatross.  Aircraft were also embarked on other ships of the RAN, including HMAS Sydney, HMAS Tobruk and HMAS Stalwart.  Initially the serial numbers were WA200 to WA226, these later being changed to N7-200 to N7-226.

The operational days of the Wessex came to an end when one aircraft suffered a catastrophic transmission failure at 305 m (1,000 ft) over the sea.  Subsequently they were used in the transport role until 1989 when the type was de-commissioned.  After withdrawal a number were placed on display at Museums around the country.

In early 2019 HARS at Albion Park, NSW received two examples from the RAN, the first being N7-222 (Code 832) which was assembled and placed on display, the second N7-203 (Code 813) was conveyed to the HARS satellite museum at Parkes, NSW, both aircraft being restored for display purposes.

The civil variant of the Wessex, the Mk 60, has also been seen in this region in the civil role, being operated mainly in Western Australia by an English company, Bristow Helicopters, this model being fitted with two 1,007 kw (1,350 shp) Bristol Siddeley Gnome turboshafts. This company has a large fleet of helicopters which have been used to supply oil-rigs off the Australian coast and all around the World. These were operated for a few years but were replaced by the larger Puma and Super Puma helicopters.

Those machines registered in Australia have included Model 60/1 VH-BHX (c/n WA694 – ex G-BBNG, VR-BEY, G-BBNG, PK-HBO, N6268N) initially registered in July 1969 and exported to the UK as G-AWXX in October 1981;  VH-BHC (c/n WA561 – ex PK-HBQ, G-AVNE, G-17-3) registered in June 1971 and exported to Malaysia in November 1973 as 9M-ASS;  VH-BHE (c/n WA686 – ex G-AWOX, VR-BCV, G-AWOX, G-17-1) registered in April 1972 and exported to the UK; VH-BHI (c/n WA503 – ex G-BGER, G-603 [Ghana Airforce]) registered in March 1979 and exported to the UK in August 1979;  and VH-BHL (c/n WA562 – ex G-AVEW, G-17-1) registered in April 1968 and destroyed by fire on 2 June 1969 near Port Samson, WA in February 1975.

In 2000, following the retirement of the type by the Royal Air Force, a number of HC Mk 2s were obtained, shipped and converted at Christchurch, NZ for civil work, the first becoming ZK-HVK (c/n XS509) with Metro Air.  Later a further six were obtained for forestry work including logging operations with Wessex Air Ltd of Christchurch, and those include: ZK-HBE (c/n XS677); ZK-HBF (c/n XT606), G-AZBY and 9G-DAN.

One (c/n WA740 – ex G-AZBY, 5N-ALR, G-AZBY, G-17-5) was imported to New Zealand and painted as ZK-IDL, although this registration was never allotted to the aircraft.  For some years it was painted with advertising in the car park of the Imperial Discount Liquor Store in Christchurch.

It seems at least seven airframes were imported to New Zealand in 2004 for HeliLogging.  Serials of these machines imported include XR511 (c/n WA136), XR588 (c/n WA121), XS675 (c/n WA194) and XV730 (c/n WA625).

On 19 September 2018 three Wessex HC.2 frames were delivered to the Classic Fighters Museum at Tauranga.