Ship-based helicopters: what's hot and what's not.

The earliest shipborne helicopters were dedicated to rescuing crews from aircraft that had ditched near carriers while attempting to take off or recover. As their size and power increased, helicopter roles expanded to include cargo transport, search and rescue, armed assault, anti-submarine warfare (ASW), anti-surface vessel warfare, over-the-horizon targeting, mine laying and countermeasures, and airborne early warning.

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Realistically, the lower end of the naval helicopter range is illustrated by the 2.6-tonne, twin-engined Eurocopter AS 555 Fennec (the TwinStar on the commercial market), which can be operated from quite small vessels. Powered by two 388-kW Turbomeca Arrius 1A engines, the baseline AS 555MN can be equipped with a Telephonics RDR-1400R radar. The AS 555SN can additionally carry a lightweight anti-submarine torpedo, such as the 244-kg EuroTorp A244/S. Recent orders include six AS 555SNs for the Royal Malaysian Navy, which will use them in training and over-the-horizon targeting duties.

Appreciably larger ships are required to operate the 4.6-tonne Eurocopter AS 565 Panther, equipped with two 729-kW Turbomeca Arriel 2Cs. The AS 565MB is the basic naval version, while the AS 565SB can carry four MBDA AS15TT anti-ship missiles or two lightweight torpedoes. It is typically fitted with a Thales Agrion 15 radar, but it can carry a dipping sonar or mad (magnetic anomaly detection) system. Its cabin is large enough to accommodate ten marines.

Recent sales of naval Panthers (the military version of the Dolphin) have included two for the Mexican Navy, which has options on eight more. These aircraft, which were delivered in June 2005, will be operated from Mexican Coast Guard vessels, in parallel with ten much lighter (2.6-tonne) upgraded Eurocopter BO 105s. The Panthers will be used for naval surveillance and interdiction missions, as well as coast guard duties such as search and rescue and drug-enforcement. Eurocopter has sold over 250 Panthers including 78 of the maritime version.

One of the most widely used naval helicopters is the multi-role Agusta Westland Lynx series, of which almost 500 have been built including over 200 marinised aircraft. The Lynx was designed to operate from frigates under sea state six conditions. Special features to facilitate operations from a highly mobile deck include a harpoon deck-lock, and main-wheel units that can be towed outboard.

The British Royal Navy Lynx HMA8 is equipped with a Sclex Sensors and Airborne Systems Seaspray radar, a Sea Owl thermal imager and an ASQ-18 active dipping sonar by L-3 Communications. It can carry MBDA Sea Skua anti-ship missiles and a variety of depth charges and torpedoes (Selex S&AS, owned 75% by Finmeccanica and 25% by BAE Systems, was formed in May 2005 by the merger of the avionics division of Galileo Avionica and BAE Systems Avionics). The Sea Owl has now been superseded by the Selex Titan that is on German Lynxes.

The latest production variant is the 5.33-tonne Super Lynx 300, with a glass cockpit and two 1000 kW LHtec CTS8004N engines. Recent naval orders have included six for Malaysia, four for South Africa and two for Thailand. The Royal Malaysian Navy may buy up to four more if plans for extra offshore patrol vessels are put into effect. The aircraft delivered to the Royal Thai Navy are equipped only for training and utility duties, and may later be augmented by six more equipped for antisubmarine and search and rescue roles.

In March 2005 the Future Lynx, based on the Super Lynx 300, was named as the British Ministry of Defence's preferred choice to satisfy its Future Rotorcraft Capability (FRC) requirement, to cover both British Army and Royal Navy needs. The naval element is the Maritime (Surface) Attack requirement, currently valued at only 30 aircraft, despite the Navy having stated a need for at least 37 and ideally 55. A go-ahead for the FRC has been delayed until early (or later) in 2006. The Future Lynx for the Royal Navy is expected to have an electro-optical payload and a radar with an electronically-scanned array. There have been references to the possible adoption of the Selex S&AS Seaspray 7500E, as was chosen for the US Coast Guard Lockheed Martin HC-130H radar upgrade programme.

As an alternative to buying more Lynxes, the Royal Thai Navy may have its existing six Kaman SH-2F Seasprites upgraded with 1285 kW General Electric T700-GE-401 engines and refurbished to 6.44-tonne SH-2G Super Seasprite standard.

The SH-2G is marketed by Kaman both as a new-build aircraft, instanced by the five SH-2G(NZ) aircraft purchased by New Zealand, and as a conversion of the ex-US Navy SH-2F held in desert storage. The latter procedure was employed in the cases of Australia with eleven SH-2G(A)s, and Egypt with ten SH-2G(E)s.

The SH-2G(E) is used with dipping sonar in the ASW role, while the Australian and New Zealand versions appear to be more concerned with ASuW, armed with the Kongsberg AGM-119B Penguin and Raytheon AGM-65D Maverick respectively. The SH-2G(A) is also cleared for the 304-kg EuroTorp MU/90 Impact torpedo.

Chile is reportedly considering the acquisition of the 5.5-tonne Hindustan Aeronautics (Hal) Dhruv (Sanskrit for Pole Star), which has been developed with the help of Eurocopter Deutschland. The Dhruv first flew in 1992 and entered production in 2002, initial deliveries going to the Indian Coast Guard.Hal is increasing its annual production rate from 18 to 30 units based on planned orders for over 300 aircraft, including 110 for the Indian Army, 50 for the Navy and 150 for the Air Force. Deliveries to date include six for the Indian Navy, but these are now being used only as light transport helicopters. Hal is now developing an anti-submarine Dhruv and will later develop an ASuW version.

The Dhruv is powered by two 825-kW Turbomeca TM333-2B2 engines, but these are to be superseded by the new 900-kW Turbomeca Ardidan 1H. The bird will be known in India as the Shakti. This began bench tests in late 2005, and flight tests are due to start in July 2006. Hal is providing an eleven per cent contribution to its development and will manufacture 21% of the engine. The company hopes to sell 600 Dhruvs.

One of the most important developments in this field is the US Marine Corps H-1 Upgrade Program, representing the creation of 100 UH-1Y utility transports and 180 AH-1Z attack helicopters by 2014. Both types have four-blade rotors and employ 1285 kW General Electric T700-GE-401 engines, giving a maximum take-off weight of 8.4 tonnes. All the AH-1Zs will be converted AH-1W SuperCobras, but only the first two Lots of UH-1Ys (totalling eleven aircraft) are to be conversions, since this process (although less expensive) removes the aircraft from service for a considerable period. The remaining UH-1Ys will be new-builds, with deliveries beginning in 2008.

The first examples of either type were handed over on 15 October 2005 for final operational evaluation. The principal export prospects for the AH-1Z are Turkey, requiring 50 attack helicopters with a further 41 on option, and Taiwan. Turkey has abandoned plans to manufacture its new attack helicopter in-country, but Taiwan, which has an initial requirement for only 30 (of an eventual total of up to 75), is demanding a production licence. Taiwan already makes tail booms for the UH-1Y and AH-1Z. Over 16,000 UH-1s have been produced, hence large numbers are available for upgrading to UH-1Y standard.

The ten-tonne Sikorsky SH-60 Seahawk, of which the US Navy has over 200 examples, is exported as the S-70B, used by seven navies. Recent S-70B orders have included twelve for Turkey (with five more on option) and six for Singapore, with both countries taking deliveries in 2008. Mitsubishi is licence-producing a new variant, the SH-60K. The first delivery took place in August 2005.

The new H-60 generation for the US Navy is represented by the MH-60R Seahawk and the MH-60S Knighthawk. Although Sikorsky is the prime contractor for both airframes, Lockheed Martin is prime for MH-60R systems integration and provides the common cockpit avionics suite for both aircraft. Both models are powered by two 1400-kW General Electric T700-GE-401C engines.

The multi-mission MH-60R will be the deployed fleet's primary anti-submarine and anti-ship platform, replacing US Navy SH-60B/F Seahawk in battlegroup protection duties. Other roles will include surveillance, communications relay, Sar, naval gunfire support, logistics support and personnel transfer. The procurement of 254 MH-60Rs is to be completed by 2015. First flight took place in July 2005, and initial operational capability (IOC) is due to be achieved in 2006.

The MH-60S, which has the larger cabin of the US Army's UH-60L, is to replace the US Navy CH-46 and HH-60H in the VertRep and Csar roles. Organic airborne mine countermeasures has recently been added as another primary mission, using two mine detection and three neutralization systems. Recognising that the MH-60S must be capable of operating in a high-threat environment, it will now incorporate some of the weapon system features of the MH-60R, including a flir sensor and provisions for the Lockheed Martin AGM-114 Hellfire missile and the shallow water Raytheon Mk 54 torpedo. The mission kit allows the crew to fire laser-sighted 7.62 mm machine guns from the cabin windows and 12.7 mm weapons from the side doors. The US Navy plans to acquire 237 examples of the MH-60S. The first production aircraft flew in January 2000, and IOC is scheduled for 2006.

Although the eleven-tonne Eurocopter EC 725 is not intended to be based on ships in the long term, the French Air Force requires it to be qualified as 'fit for deck landings' by the French Armament Authority (DGA) in order to fulfil its Csar role and fight maritime terrorism. Landing trials on the frigate Courbet began in October 2005, and the EC 725 will also be tested on the carrier Charles de Gaulle.

One of the best-selling medium helicopters is the 10.6-tonne NHIndustries NH90, which is currently the subject of firm orders from eleven nations for 357 aircraft, with options on more than 120. In addition, Belgium (requiring ten aircraft), New Zealand (eight to ten) and Spain (45 of an eventual 100) have selected the NH90 and are currently negotiating contracts. NHI is jointly owned by Eurocopter (62.5%), Agusta Westland (32%) and Stork Fokker (5.5%).

The NH90 is produced in two principal versions: the NFH, designed for operation from Nato frigates in conditions up to sea state five, and the TTH tactical transport helicopter for land-based use. It can be equipped with two 1735-kW Rolls-Royce Turbomeca RTM332-01/9 engines, or 1520-kW T700/T6As, the latter having been jointly developed by General Electric, FiatAvio and Alfa Romeo Avio. Orders for the NFH version consist of 27 for France, 46 for Italy and 20 for the Netherlands.

Russia's contribution in this category is the helicopter family based on the eleven-tonne Kamov Ka-27, with contra-rotating rotors and a four-leg undercarriage. The Ka-27 is a ship-based ASW and Sar helicopter, designed to operate from a highly mobile deck ten metres long and ten wide. Its rotor system is smaller in diameter than the conventional arrangement (25% smaller than for a Mil Mi-17), facilitating use from a small deck. The Mi-27 entered service in 1981 and it is believed that around 270 were built. The Russian Navy is reported to have approximately 85 Ka-27s still in service, as well as about 30 examples of its Ka-29 derivative.

The export version of the Ka-27 is the Ka-28, which has increased fuel capacity and a twelve-tonne maximum take-off weight. It is powered by two 1640 kW Klimov TV3-117VMA engines. Small numbers have been sold to China, India and Vietnam. The Ka-28PS is a dedicated Sar helicopter with ASW equipment removed. Armament options include one lightweight torpedo and ten Plab 250-120 depth charges. The Indian Navy, which has around 15 Ka-28s, has been offered the Vympel Kh-25 (AS-20) 'Harpoonski' anti-ship missile as an upgrade.

The 11.5-tonne Ka-29 is described by Kamov as a transport combat helicopter. It entered service in 1987 and the Russian Navy is believed to have about 60. The Ka-29 is designed to land an assault team of twelve fully-armed marines, and to provide fire support and transportation of supplies. The cockpit and powerplant areas are armoured against small arms strikes. The transport version of the Ka-29 has a flexibly-mounted 7.62 mm Gaffing gun in the nose, while the attack version is armed with two fixed 30 mm Shipunov 2A42 cannon, as used on the Ka-50 and Mil Mi-28. It can also carry two 23 mm gun pods, eight KBM 9M114/120 (AT-6/9) air-to-ground guided missiles or up to 80 rockets of 80 mm calibre.

The Ka-31 is a dedicated AEW derivative of the Ka-29. It first flew in 1987 and entered service in 1997. The Indian Navy is reported to have nine Ka-31s. The landing gear units are raised in flight to provide a clear field of view for the rotating ventral radar antenna, a large rectangular array which, for landing and take-off, is stowed against the underside of the fuselage.

The Sikorsky S-92 is marketed primarily as a civilian helicopter, the military H-92 Superhawk being given lower priority. However, in 2004 the Canadian Forces selected the MH-92 to replace the Sea King in ASW operations and ordered 28 (designated CC-148 Cyclone) for delivery from 2008. The 12.84-tonne H-92 is powered by two 1880 kW General Electric CT7-8C engines.

The 14.6-tonne, three-engined Agusta Westland International (formerly EHI) EH101 is marketed in both land-based and naval forms. It employs either the 1688-kW Rolls-Royce Turbomeca RTM322-02/8 or the 1490-kW General Electric CT7-6A. The current order total is 145 units, including 44 for Britain's Royal Navy, 16 for the Italian Navy (eight for ASW/ASuW duties, four utility transports and four AEW aircraft) with up to 20 more required, and 26 VH-71As for the US Navy-funded presidential helicopter squadron. Lockheed Martin is prime contractor for the VH-71A, and 19 of these aircraft will be built by Bell Helicopter. In addition, Kawasaki is building 14 EH101s for the Japan Maritime Self-Defence Force. Designated KHI-03, these aircraft are to replace the S-61 in Antarctic support duties and (equipped with the EDO Oasis system) the MH53E in the airborne mine countermeasures role. The 15 Canadian Forces CH-149 Cormorants are land-based Sar aircraft, based on the civil EH101.

Powered by two 4586-kW Rolls-Royce T406-AD-400 engines, the Bell Boeing V-22 Osprey is the world's first production tilt-rotor aircraft. Maximum weight ranges from 21.5 tonnes in the vertical take-off mode to 27.4 tonne using short take-off. The V-22 was designed to fulfil the requirements of the US Marine Corps for amphibious/vertical assault, and those of USsocom (US Special Operations Command), plus US Navy needs in the strike rescue context. In June 2005 the MV-22 successfully completed operational evaluation. In September 2005 the V-22 received Pentagon approval for full-rate production, which will increase annual delivery rate from the present eleven units to 48 by 2018. Over 70 V-22s have already been flown. The US Marine Corps is to receive 360 MV-22s, USsocom 50 CV-22s and the US Navy 48 HV-22s. There have been reports that the Marine Corps may order up to 180 AV-22 gunships, and that the makers hope to win export orders from Israel, Japan and the UK.

In December 2005 the Pentagon authorised the Marine Corps to launch the $ 4.4 billion development of the Sikorsky CH-53K or Heavy Lift Replacement (HLR) project, formerly CH-53X. The HLR is to replace the three-engined, 33.3-tonne CH-53E, of which the service currently has around 140. Some of these will start reaching their safe fatigue life limit in FY2011. An ISDD (Initial System Development and Demonstration) contract worth $ 8.8 million was signed with Sikorsky on 3 January 2006, with the main SDD contract scheduled to follow two months later.

The engine proposals are reportedly based on the General Electric T64, the Honeywell T55, the Pratt & Whitney Canada PW150 and the Rolls-Royce AE1107. Some of these could provide a take-off weight of up to 45 tonnes. The CH-53K will have a glass cockpit, new main rotor blades with anhedral tips and an elastomeric rotor head. It is required to carry a payload of 12.25 tonnes over a 225 km range. The CH-53K is scheduled to fly in FY2011, and the US Marine Corps is to receive the first of 156 in 2015.

This HLR has successfully avoided incorporation in the US Army-led Joint Heavy Lift (JHL) rotorcraft, which is also to fulfil Navy requirements associated with its new sea-basing strategy. It is felt that JHL will not be available until 2025, and will be too large for the ships planned for US Marine Corps operations. The service sees the JHL more as a possible KC-130J replacement.