Protecting the Air from the Sea

JMSDF fleet
Construction is due to begin shortly of the first of two new advanced destroyers based on the existing JMSDF designs. They will participate in a regional defence shield against ballistic missiles, as well as providing area air defence for the JMSDF fleet. (US Navy)

Advances in the capabilities of surface-to-air missiles are being matched by developments in maritime air defence sensors. There is therefore demand for increasingly sophisticated, dedicated air defence vessels. This article analyses a number of the most significant recent developments in this field.

Australia is one of several countries surveyed in this article which is pouring investment into its air defence surface combatants. Currently in build for the Royal Australian Navy (RAN) is a trio of 6250-tonne, 147-metre/m (482-feet/ft) warships, designated by the RAN as Air Warfare Destroyers (AWD). These vessels will replace the RAN’s ageing ‘Adelaide’ class frigates and are urgently required to provide area air defence for RAN task groups, particularly as the fleet’s highest value surface units, the two new ‘Canberra’ class amphibious assault ships, are very lightly armed. The AWDs will also have significant anti-submarine, and Anti-Surface Warfare (ASuW) capabilities. These are technologically advanced, and potentially, highly capable, warships, although they are experiencing a complex, trouble-plagued gestation.

Following the green light for the programme in 2007 which uses a design based on an adaptation of the Armada Española (Royal Spanish Navy) ‘F-100’class frigates which are built by Navantia, Canberra opted for a modular approach to construction. Construction is being performed by the AWD Alliance, comprising the Australian government’s Defence Materiel Organisation, ASC shipbuilders and Raytheon’s Australia subsidiary. After numerous changes of plan, a total of 31 modules per ship are being constructed by ASC, BAE Systems and Forgacs in Australia, and Navantia in Spain and the UK, while mast structures are being built by MG Engineering of Australia. Design, engineering and contractual problems have combined to delay the programme by some three years. The project nevertheless reached a major landmark in early May 2016 with the activation of a number of combat systems on the first-of-class, the HMAS Hobart, which had been launched about a year previously.

The armament fit of the AWD is comprehensive. Its main weapon system is the Lockheed Martin Mk.41 48-cell vertical missile launcher, able to fire Raytheon RIM-161 Standard Missile-2 (SM-2) Block-IIIB and Raytheon RIM-162 Evolved Sea Sparrow (ESSM) surface-to-air missiles (SAMs). The vessel’s Anti-Ship Missile (AShM) capability is provided by two quadruple canister launchers for Boeing RGM-84 Harpoon family AShMs. The vessel’s gun armament takes the form of a BAE Systems’ 127mm weapon backed up by two Rafael Advanced Defence Systems Typhoon 25mm automatic cannon. The ‘Hobart’ classes’ ASW fit consists of Eurotorp MU-90 torpedoes fired from two twin Babcock Mk.32 Mod.9 launchers. The very advanced and capable Sikorsky MH-60R helicopter is embarked for ASW and ASuW. All of these systems are tied together using Lockheed Martin’s Aegis Combat System integrates, a range of sensors including the Lockheed Martin AN/SPY-1D(V) S-Band (2.3-2.5/2.7-3.7 Gigahertz/GHz) radar and Northrop Grumman AN/SPQ-9B X-band (8.5-10.68GHz) pulse Doppler horizon search radar. Finally, the ships’ propulsion is provided by twin General Electric Marine gas turbines and a pair of Caterpillar diesel engines in a Combined Diesel or Gas (CODOG) arrangement, giving a top speed of over 28 knots (52 kilometres-per-hour).

AWD’s director of communications Danielle De Santis confirmed that the ship will feature “the most modern equipment, including the RIM-161 SM-2 Block-3B and RIM-162 SAMs, and Raytheon’s PhalanxBlock-1B Close-In Weapons System (CIWS), and the latest Curtis-Wright ASIST (Aircraft Ship Integrated Secure and Traverse) system to facilitate the secure landing, deck handling, and recovery of (the ship’s) helicopter.” Ms. De Santis confirmed that the current scheduled in-service dates for the three ships of the class are as follows: HMAS Hobart (June 2017), HMAS Brisbane (July 2018) and HMAS Sydney (December 2019). The original total cost estimate for the AWD was $8 billion; Canberra’s 2015 project overview estimated that it was likely to run $1.2 billion over budget, while the AWD Alliance was not able to supply an up-to-date estimate.

Royal Navy

Like the RAN, the Royal Navy is also replacing its frigates, chiefly the ‘Duke’ class with the Type-26’ class frigate, as part of the Global Combat Ship project initiated in 1998. The go-ahead to start the final design and pre-manufacturing work on the ‘Type 26’ class was given to its prime contractor BAE Systems in 2010. The ship will be optimised for ASW, but will also be well equipped for both air defence, and direct support of land operations. Priority roles for this 8,000-tonne, 150m (492ft.) warship will be escorting the Royal Navy’s new ‘Queen Elizabeth’ class aircraft carriers, and participating in international security and humanitarian and disaster relief operations.

The ‘Type-26’ class’ strong air defence capability is provided by a 48-cell vertical launcher for MBDA Sea Ceptor SAM. The vertical launchers will be large enough to enable possible allocation of Raytheon BGM-109C Tomahawk surface-to-surface cruise missiles. BAE Systems Stingray torpedoes, both ship and helicopter launched, will enable ASW, with the ship’s gun armament being a BAE Systems Mk.5 127mm mounting, backed up by two MSI Defence Systems automatic DS30M Mk.2 30mm cannon, two Phalanx CIWS. The ships’ sensor outfit consists of a BAE Systems Type-997 Artisan naval surveillance radar, a Kelvin Hughes SharpEye navigation radar, a Thales’ Type-2087 towed array, and Type-2050 bow sonars. The ‘Type 26’ class will be able to operate two AgustaWestland/Leonardo HM.1/2 Merlin or HMA.1 Wildcat helicopters for ASW/ASuW or one Boeing HC.2 Chinook heavy-lift helicopter. The ships’ propulsion is achieved by a CODOG system combining two Rolls-Royce MT30 gas turbines, four MTU diesel generators and two electric motors.

Sea Ceptor SAM system
Although its prime role will be anti-submarine warfare The ‘Type 26’ class’ new Sea Ceptor SAM system, and its accompanying Type-997 3D radar, will add significantly to the Royal Navy’s air defence capabilities. (Trevor Hollingsbee)

In December 2015 the British Government announced that eight, rather than the originally planned 13, ‘Type 26’ class frigates will be ordered, but that at least five smaller, cheaper, general purpose frigates, designated as the ‘Type 31’ class, will also be constructed, using the funds freed up. The UK Ministry of Defence official 2015 estimate for 13 ‘Type 26’ class vessels was a cost of $16.5 billion. In-service date for the first Type 26 meanwhile remains uncertain. Concepts now being considered for the ‘Type 31’ class are known to include modified versions of the BAE Systems ‘AlKhareef’ class corvette (in use with the Royal Navy of Oman), the ‘River’ class Offshore Patrol Vessel (OPV) in service with the Royal Navy, and Babcock Defence’s ‘Roisin’ class OPV in service with the Irish Navy, as well as BMT’s new ‘Venator’ class frigate design, and a downscaled variant of the ‘Type 26’ class.


Across La Manche (the English Channel), the Marine Nationale (French Navy) are planning to build two Fregate de Défense Aériennes (FREDA/Air Defence Frigate) versions of the ‘Aquitaine’ class multi mission frigates that the navy currently operates. Marion Bonnet, a spokesperson for DCNS which builds the ‘Aquitaine’ class, and which will also build the FREDA ships, told Armada that the size of the FREDA vessels will “be the same as that for the standard ‘Aquitaine’ class.” Their air defence armament will consist of a total capacity for 32 MBDA Aster-15/30 SAMs. MBDA’s Exocet MM40 AShMs will also be fitted, and there will be capacity for the possible retrofit of land attack missiles. Cost estimates specific to the FREDA project have not yet been made available, although the 2015 French government estimate for the ‘Aquitaine’ class costs was $755.5 million per unit.

FREDA air defence frigates
France’s new FREDA air defence frigates, ordered in place of two cancelled ‘Horizon’ class destroyers for the Marine Nationale, will have MBDA’s Aster-15/30 as its primary SAM system. (DCNS)


Away from Europe, over the past 20 years the People’s Republic of China’s People’s Liberation Army Navy (PLAN) Navy has emerged as a leading maritime power. The PLAN fleet already includes some 90 frigates and destroyers, and details are emerging of a significant new air defence destroyer project. According to local reports, at the end of 2014 the first ‘Type 055’ class destroyer was laid down at the Changxingdao-Jiangnan Shipyard. These reports, and others indicating that construction of a second example commenced at Dalian, northeast China in 2015, remain unconfirmed, but a training mock-up of the new warship has been identified on shore at Wuhan, central China.

A range of reports, including in the official Chinese media, indicate that the destroyer will displace around 10,000 tonnes, with a length of 175m (574ft). Its armament will reportedly consist of a Zhengzhou Mechanical-Electrical Engineering Research Institute Type H/PJ38 130mm naval gun and a 713th (Research) Institute H/PJ-11CIWS, both mounted forward, and a total of 128vertical launch cells, fitted fore and aft. The cells will be capable of firing China Precision Machinery Import-Export Corporation HQ-10SAMs, China Aerospace Science and Industry Corporation YJ-100 AShM and, probably, as-yet-unspecified land attack and anti-submarine missiles. Two medium naval support helicopters will be carried. The superstructure of the Type 055 appears to have a low radar cross section design. Available imagery also indicates that four S-Band three-dimensional (altitude, bearing and velocity) fixed array radar antennae are fitted around the forward superstructure, together with an integrated mast containing components of the ship’s radar, electronic support measures and communications.

A vessel of this size, and capability, will add to the combat capabilities of the PLAN. According to Lyle Goldstein, associate professor of China Maritime Studies at the US Naval War College: “Like the Aegis (Combat Management System, see above) destroyers that formed the model for its predecessors, the ‘Type 055’ class’ main mission is certain to be fleet air defence, including for Beijing’s nascent carrier battle groups.” Beijing might well also be trying to match the defence Russia Navy’s revived ‘Kirov’ class nuclear-powered cruisers and the US Navy’s new ‘Zumwalt’ class destroyers bestow on their respective fleets.

PLA Navy
This new, large destroyer, the first examples of which might already be in build, are intended both to boost the PLA Navy’s already substantial inventory of air defence vessels, and to enhance the status of the PLA Navy. (


The PLAN’s rival Japan Maritime Self Defence Force (JMSDF) has operated its defence destroyers equipped with the Aegis CMS since 1993. The JMSDF’S existing ‘Kongo’ class Aegis CMS-equipped destroyers and the two improved and enlarged ‘Atago’ class variants are based on the US Navy’s ‘Arleigh Burke’ class destroyers. These warships are at the core of the order of battle of an increasingly ambitious and outward-looking JMSDF, and provide area air defence for Japanese battle groups and allied assets, as well as in conjunction with Republic of Korea Navy and US Navy warships. The core of the current JMSDF Aegis-equipped destroyers’ area defence capabilities is a Lockheed Martin Mk.41 vertical launch system consisting of cells fitted forward and aft. The cells can fire a mix of RIM-162 SM-2MR and SM-2MR SAMs. Their main gun armament is a Leonardo/Oto Melara 127mm Compact Gun whereas the ‘Atago’ class have a Japan Steel Works Mk.45 Mod.4. Last ditch defence against AShMs is provided by two Phalanx CIWS. Canisters for up to eight RGM-84 (the Mitsubishi Type 90 AShM on the ‘Atago’ class) are fitted for ASuW, while fixed anti-submarine weaponry consists of two triple torpedo tubes capable of firing Raytheon Mk-46 torpedoes. The ship’s sensors include the AN/SPY-1D naval surveillance radar and OQS-102 bow mounted sonar, while a Sikorsky SH-60J naval support helicopter is carried. There are advanced plans in hand to build two additional, improved Aegis destroyers, to a design based on that of the existing vessels. In September 2015 Japan’s Ministry of Defence announced that two ’27-DD’ class destroyers were to be constructed, with an empty displacement of 12300 tonnes, compared to the 10000 tonnes of the ‘Atago’ class. Planned features of particular note include Northrop Grumman AN/SPQ-9B surface search radar, and combined gas turbine/electric and gas turbine (COGLAG) propulsion. The ships are scheduled to enter service in 2020-21, and are estimated to cost $1.5 billion per vessel.

JMSDF fleet
Construction is due to begin shortly of the first of two new advanced destroyers based on the existing JMSDF designs. They will participate in a regional defence shield against ballistic missiles, as well as providing area air defence for the JMSDF fleet. (US Navy)


There is a definite tendency for air defence ships to increase in size. Reasons for this include the requirement to fit large numbers of vertical launch SAM canisters, and increasingly large and complex surveillance and detection systems, in order to cope with multiple attacks by advanced missiles. Also, many navies now can only afford limited numbers of escort vessels, so air defence ships are, in addition, increasingly being given comprehensive anti-submarine and above surface warfare capabilities in an effort to ensure their survivability in multi-threat environments. Delineation between the categories of destroyer and frigate is therefore blurring; this is a trend which seems certain to continue.

by Trevor Hollingsbee