Carrier 2000: A Consideration of Naval Aviation in the Millennium

In 1994 the UK Ministry of Defence (MoD) embarked upon a series of concept studies to examine the options for replacing the three Invincible-class aircraft carriers in current service. The conclusion of this work was to lead to the generation of a Staff Target for presentation to and approval by Ministers in late 1997. The study work has now been completed, but the arrival of a new Labour Government in May 1997 prompted the initiation of a Strategic Defence Review (SDR) which included a fundamental assessment of whether or not the Royal Navy should operate aircraft carriers in the future and if so, what should be their principal capabilities.

Naturally, this delayed Ministerial approval of the Staff Target for The Future Aircraft Carrier (CVF) until the White Paper summarising the future of UK Defence was presented to Parliament in the summer of 1998.

Aim

The aim of this article is to establish the need for CVF within the future UK force structure and to discuss the principal capabilities which should be included in such a vessel.

The genesis of the Invincible-class

The analogies between CVF and the Royal Navy’s last attempt to persuade a Labour Government on the need for a new class of aircraft carrier are inevitable. In 1966 the building of CVA 01, Britain’s first nuclear powered aircraft carrier, was cancelled as a result of the defence review initiated by a new Labour government entering office after a lengthy period of Conservative leadership. There are other parallels; the Royal Air Force (RAF) are seeking a Future Offensive Air System (the major component of which is likely to be a future manned aircraft) in similar time frame to CVF, in 1966 the Air Force were seeking a new offensive aircraft, the TSR2. Similarly, although the UK economy is arguably stronger now than it was in the mid-1960s, both in 1966 and today each Government perceives a need to save money on Defence expenditure in preference for ‘higher priority’ claims to the public purse.

However, in 1966, the acrimonious wrangling between the Air Force Department and the Admiralty succeeded only in providing sufficient evidence for the Treasury to make a case for cancelling both projects, albeit the TSR2 survived rather longer than CVA 01. In contrast, there is now a common understanding of the complementary nature of sea and land-based air power across the MoD, and there is common agreement on the need for a balanced military capability to emerge in the SDR conclusions.

There is much folklore surrounding the cancelling of CVA 01 with the Air Force Department being accused of conveniently displacing Australia by some 500 miles to support their ‘Island Base’ alternative to carriers, and poor Staff Work in the Admiralty being two of the more commonly told accounts. In fact, whilst there might be some truth in all of the stories, it seems the principal cause of failure was that the case for the carriers was based solely on the need to operate East of Suez. When the Government determined that the UK could no longer afford or justify the role of ‘global policeman’ and aligned our defence priorities squarely with NATO in Europe, the case for CVA 01 was lost. Post-1966, and apart from the Polaris force, the Royal Navy’s principal role was to provide Anti-Submarine Warfare (ASW) protection to USN Carrier Battle Groups in the Greenland, Iceland, UK (GUIK) Gaps as part of NATO’s Forward Maritime Strategy.

The Forward Maritime Strategy aimed to keep the large Soviet nuclear attack submarine fleets contained in the sea areas north of the Greenland, Iceland, UK gaps to allow American reinforcement and re-supply shipping unhindered passage across the Atlantic and thus ensure any land war in Europe could be credibly fought without premature recourse to nuclear weapons. To prosecute successfully so many Soviet nuclear submarines, the Royal Navy perceived the need to deploy large numbers of ASW Sea King helicopters in the North Atlantic. The Invincible-class was conceived as the platform for these aircraft and also as the afloat headquarters of the Commander ASW Strike Force. The initial Staff Requirement called for a ship capable of operating nine Sea King helicopters in the North Norwegian Sea and with Command, Control, Communications and Intelligence (C3I) facilities to support the NATO command task. The ship was termed a ‘through deck cruiser’, partly to avoid using ‘aircraft carrier’ so soon after the demise of CVA 01 but, more accurately, because these ships were to fulfil a traditional cruiser role (extensive command facilities, the Sea Dart weapon system, etc.) and were built to cruiser construction standards. Initially the design did not feature a ‘through deck’ but the superstructure was eventually off-set to starboard.

This decision, coupled with the successful development of the Harrier Short Take Off, Vertical Landing (STOVL) aircraft, allowed five Sea Harriers to be added to the Invincible’s air group. The Sea Harriers were required to eliminate the threat from Soviet reconnaissance aircraft which could direct air attack against NATO maritime forces. However, NATO land-based fighters were perceived as the main protection from the classic Soviet Regimental Badger raid, leaving the Fleet Air Arm (FAA) with only a tenuous role in air defence and a very limited fixed wing capability.

Of course, in 1982 the principal task for the Royal Navy was temporarily moved 8,000 nautical miles to the south and Invincible demonstrated the remarkable versatility of these ships, embarking and operating over 20 aircraft during the Falklands conflict. The Sea Harrier also came of age. Apart from a very few RAF Harrier GR3s, the Sea Harriers were the only fixed wing combat aircraft in theatre and were tasked on air defence, reconnaissance and ground attack, achieving considerable success in all roles. Without the Sea Harrier and ships capable of operating them, it is doubtful whether the UK could have restored British Sovereignty in the Falklands. The success of the Invincible-class STOVL carriers led to the acceptance of this type of ship as a credible and affordable means of deploying air power. At a fraction of the cost of a nuclear-powered ship with Conventional Take Off & Landing (CTOL) aircraft, the STOVL carriers proved an attractive option and are now in Spanish, Italian, Indian and Thai service.

Following the Falklands conflict, the Invincible was retained in the Royal Navy (there had been a plan to sell her and run only two ships in the class) and the air group evolved to a standard mix of 6-8 Sea Harriers, 7-9 Sea King ASW helicopters and 3-4 Sea King Airborne Early Warning (AEW) helicopters. This was a far more potent air group than that perceived during the initial design, but one still principally geared to maritime tasks such as ASW, maritime air defence and attack of opposing naval forces.

Strategic change

Since the demise of the Soviet Union, the end of the Cold War and almost a decade of NATO readjustment, it is now widely acknowledged that the threat of general war and, in particular, direct threat to the UK has receded and, perhaps arguably, continues to recede.

Certainly, it is not credible to consider general war without considerable warning time, and it is therefore no longer necessary to keep a large military force at short notice to respond to such threat. However, identification of what the appropriate indicators and warnings may be, and whether there will be the political will to respond to early indications of a future hostile act, remains an issue, but one beyond the scope of this article. A regional crisis within NATO is, therefore, likely to be the largest scale military action that the UK would have to respond to with limited warning. NATO regional crisis thus becomes a military force driver, that is a determinant of the range and scale of forces the UK will need to sustain at relatively high states of readiness. The likelihood of a NATO regional crisis is uncertain, but, if the UK is to meet its obligations, it must sustain forces capable of making an effective and rapid military contribution in support of any NATO ally, under Article 5 of the Washington Treaty.

Of course NATO is essentially a narrow perspective of our wider security interests since UK is heavily reliant on a free market for world trade, has many nationals living abroad and still has dependent territories and security agreements such as the Five Power Defence Agreement it must honour. It is unquestionably in UK’s direct interest to promote peace and stability throughout the world and, as even the most casual review of recent world events will highlight, there are many and varied potential threats to peace and stability.

Arms proliferation is a particular concern; not only the availability of ex-Soviet military technology to third world states, but also the increasing sale of sophisticated Western technology as European and American defence manufacturers seek to offset the shrinking home market by increasing exports. Thus, in any future conflict, UK forces are likely to face weapons with similar technology to their own and will not be able to rely on a ‘quality of weapons’ advantage. In addition, and despite considerable international efforts to prevent their spread, weapons of mass destruction (encompassing nuclear, biological and chemical warheads) are becoming an increasing threat as witnessed by the recent underground nuclear tests in India and the response from Pakistan [May 1998 – Ed]. There may be some comfort in the thought that less well-developed nations do not have the ability to deliver these weapons in a direct attack on the UK and would be challenged to target a mobile maritime force, but in the hands of an unstable or fanatically inspired regime they pose a considerable regional threat. This threat is compounded if the opponent does not hold the same rational value set as that widely recognised by most NATO partners. In such circumstances, what appears an inconceivable tragedy to the West may be entirely acceptable to a regime which places a different value on human life, undermining the effectiveness of international attempts to deter conflict or uphold human rights. Instability is also insidious as the events in Bosnia so graphically demonstrated. Long suppressed but deeply held beliefs, be they religious, ethnic or inspired by other sources, have the potential to create conflict in areas of direct concern to the UK.

A further consideration, and an inevitable consequence of the world market place, is the ever expanding tapestry of military and trade alliances between nations and groups of nations. The relatively simple ‘us and them’, or bipolar strategic map of the Cold War-era has been immeasurably complicated by such factors and it is no longer possible to predict with confidence who will be coalition partners for some future crisis.

Militarily this raises a significant issue, the availability of Host Nation Support (HNS). The simple consideration as to whether HNS will be guaranteed is becoming difficult to predict, but a caveat placed on the use of host nation facilities, as imposed on occasion during the height of the Bosnia crisis and during recent events in the Near East, would seriously affect the ability to deploy a national or Allied force. Even in circumstances where HNS is ultimately granted, the diplomatic decision process could take so long that military action is complicated, undermined or negated. Finally, the maturity of host nation facilities may be insufficient to support modern aircraft with advanced support requirements such as the maintenance of low observability (stealth) features. Clearly some of the under developed nations would be challenged in this regard, but the potential new partners in NATO might also struggle to support the high technology equipment used by some of the more established NATO members.

These factors are not exhaustive but they serve to illustrate the unpredictable nature of conflict in the post-Cold War-era. In the past it was relatively simple to justify the need for a military equipment programme against a known threat for a predictable war in a known geographic location; now new military equipment must be procured with the capability to prevent, coerce or fight an unknown enemy in an unknown location with undetermined allies. The security situation faced by the UK is thus markedly different from that prevailing in 1966 and until the destruction of the Iron Curtain. Weapons proliferation, the drugs trade, terrorism, ethnic and population pressures and the breakup of some existing states all present new or greater challenges. Increased globalisation, in which all states are becoming increasingly interdependent, requires the UK to be able to act in coalition, in response to circumstances which undermine the strength and stability of the international structures upon which we and our allies depend. Furthermore, the contribution made by military forces in defusing and managing crises, through what may be described as ‘defence diplomacy’, have already been demonstrated in a wide range of day-to-day contacts and peace support operations.

The Government has acknowledged that the UK has wide international interests beyond Europe. These are most likely to be affected by events in the Gulf, the Near East and Africa and we must be ready to respond, in coalition with others, to support stability in these regions which are vital to our economic prosperity. UK interests also extend beyond these regions but the risks to them are of lesser magnitude. Whilst interests in areas such as the Far East are unlikely to drive our force structures, it is clear that forces capable of rapid deployment and sustained operations will be of great value in supporting the role of the United Kingdom’s Armed Forces ‘as a force for good in the world’.

The conduct of future military operations

In stark contrast to the well-developed and frequently practiced tactics of the Cold War, it is exceptionally difficult to plan for a future war of attrition against an unknown enemy in an unknown location. The operation is also likely to be fought alongside allies of an ad hoc coalition who may not even be NATO partners and who may have a different view on the need for military intervention than that held by the UK. Therefore, the SDR is likely to renew the emphasis on Military Tasks which assist crisis prevention, coercion and defence diplomacy. If conflict becomes unavoidable, distance from the UK, media pressures and public opinion are likely to militate against a campaign that relies on the attrition of the enemy, particularly as this will increase the risk of casualties among Allied forces. An emphasis on the doctrine of manoeuvre warfare is thus entirely coherent with the unpredictable nature of future conflict.

Operational manoeuvre is based on a philosophy of striking at the enemy’s key points rather than tackling his military might head on. The aims are to destroy his cohesion (for example by destroying his command and control infrastructure), to unbalance the enemy (in which surprise or unpredictability are key factors) and to take decisive action (to select and achieve the, possibly limited, objective) as quickly and dynamically as possible thus denying the enemy reaction time. Collectively the aim is to prevent coordinated, effective military action in preference to seeking the opponent’s defeat through the systematic attrition of his forces. Ideally the enemy is persuaded of the futility of continued conflict and surrenders.

The utility of aircraft carriers in an unpredictable world

Against this evolving strategic setting and future concept of military operations the utility of aircraft carriers can be assessed. Clearly it is no longer credible to base this assessment on predictable scenarios with accurately quantifiable threat orders of battle ranged in opposition to Allied Forces. Therefore the assessment of aircraft carrier utility has been based on accepted UK doctrine. The increased emphasis on littoral operations suggests that a CVF will inevitably be engaged in Joint and Combined Operations for the majority of missions (the littoral includes the area overland over which maritime forces are capable of projecting power and the sea areas in which they operate whilst engaged on such missions. In very broad terms it is the sea area within 200 nautical miles of the coast and up to 500 nautical miles inland from the coast). In the absence of formally issued Joint Doctrine for UK Forces the analysis examines, in turn, a carrier’s utility to maritime, military and air power doctrine. In this context maritime doctrine has three facets; power projection, sea control, and constabulary or benign tasks. The CVF contribution to military doctrine includes maritime manoeuvre and amphibious warfare, while the broader contribution of aircraft carriers to air power doctrine is more generic.

Power Projection is the use or threatened use of military force (maritime, military or air) at a distance from the UK to achieve a political aim. Specifically, the CVF could conduct:

– Combat operations against the land, which includes offensive air support operations, air interdiction and electronic and information warfare.

– Support air operations backed up by comprehensive medical and air maintenance facilities. Examples are the evacuation of civilians in a Services protected operation, the conduct of combat search and rescue missions and casualty evacuation.

– Operations in support of diplomacy, involving the visible presence or simply the possibility that the carrier may be somewhere over the horizon, poised to influence events. Carriers offer political flexibility through proportionality, unhindered by the need to gain support from a third party. Thus, the prepositioning of an aircraft carrier is a national decision which, taken quickly, may be sufficient to prevent an impending crisis. Such preventative, precautionary and pre-emptive uses of naval force are traditional applications of naval diplomacy but are only effective if escalation is credible. A carrier’s ability to rapidly increase and sustain the tempo of air operations is, in itself, an effective deterrent.

– Peace Support Operations, as exemplified by recent examples of operations in the Adriatic and Gulf of Oman, which highlight a carrier’s ability to remain independent of third party cooperation, and capitalise on its ability to move rapidly, at very short notice, to provide the correct military response, including fire support.

Sea Control. This is properly defined as the control of a sea area for one’s own, national purposes. A carrier has applicability across the following elements: The interdiction of enemy forces (sea, air and submarine), the protection of maritime trade, surveillance, establishing and maintaining maritime exclusion zones, layered protection, and precursor operations.

Without a carrier, the achievement of these tasks would require commensurately greater numbers of other assets, such as land-based air defence aircraft, surface escorts and other helicopter operating platforms.

The final element of maritime doctrine is Constabulary and Benign tasks. By definition these do not involve military action and it could be argued that a CVF would be excessively capable for such tasks. However, an aircraft carrier would dramatically increase the probability of success in many of these operations and could be expected to maximise international recognition for UK participation in such missions.

In a Joint context, military doctrine is the principal driver for a carrier’s warfighting capability: Maritime Manoeuvre has become synonymous with the contribution of maritime forces to Joint warfare in the littoral. Specifically, a CVF would contribute air support to the land forces, maximising the advantages of sea-based air power.

– The CVF could be taken under the direct operational control of the Land Force Commander who could determine the optimum position for the ‘airfield’ in relation to the land battle, determine the target priorities for the aircraft and exercise positive, dynamic control of the immediate air assets.

– The floating airfield can move in parallel with the land battle, minimising reaction time and guaranteeing appropriate fire support where and when required. This will apply to the carrier-based fixed wing and, if required, the associated Attack Helicopter force which might also be deployed from the CVF.

– Finally, the maritime task force can provide protection to the land force logistic tail – particularly as the vast majority of equipment and personnel will, inevitably, be transported by sea.

A further element of military doctrine is amphibious warfare. The UK has invested substantially in a modern amphibious warfare capability with the new amphibious helicopter support ship HMS Ocean nearing completion and the new landing ships Bulwark and Albion now under construction. Of course carrier aviation has a vital role to play in amphibious warfare as it is the only guaranteed source of offensive air support for these lightly armoured, highly mobile forces.

A traditional view of amphibious forces is to use them for theatre entry, the so-called ‘knock the door down’ capability deemed necessary to secure sea and air ports of entry for the larger follow-on forces. This is the predictable employment of amphibious capability, with an initial ‘storm the beach’ followed by consolidation ashore before ‘breaking out’ to other objectives, as exemplified during the Falklands conflict. A manoeuvrist view would be rather different, more akin to the concept of a raid where the forces move in quickly, achieve the objective and withdraw before the enemy has time to respond in a structured or ordered manner. Alternatively, the amphibious force could be used to poise on an enemy’s seaward flank as a potential and unpredictable threat causing a disproportionate and debilitating diversion of forces to repel the potential attack. All of these conceptual uses of amphibious capability rely heavily on guaranteed air support which in many circumstances can only be provided by an aircraft carrier.

Air power doctrine is the application of air power to achieve a military purpose. Here, aircraft based in the CVF are able to contribute in exactly the same manner as land-based equivalents. The recent embarkation of RAF Harrier GR7s to supplement the Sea Harrier FA2 force in the Invincible-class carriers deployed in the recent Near East crisis exemplified the flexibility of a carrier air-base. Returning to the uncertainties of time, place, enemy and ally, a carrier ensures that at least part of the UK’s offensive air power can be brought to bear in a timely manner without reliance on a third party. Similarly, by positioning the floating airfield close to the crisis area, the need for air-to-air refuelling can be minimised and combat aircraft are able to concentrate their effort in combat rather than lengthy and exhausting transits between the air base and theatre of operation. More importantly, close proximity to the battlefield enables the carrier to respond instantly to changes in operational tempo, providing offensive aircraft in direct support as the situation demands. By operating close air support aircraft from deck alert, concentrated firepower can. be applied in a far more effective manner than the limited number of aircraft that could be sustained on airborne alert from a distant airfield. Sustained combat presence is the Achilles heel of air power, but the inherent sustainability of maritime forces, enhanced and extended by replenishment at sea from the Royal Fleet Auxiliary, would enable CVF based aircraft to overcome this limitation. However, the CVF would need to be more than simply a forward operating base for fuel and weapons if sophisticated aircraft are to be kept combat ready.

Extensive maintenance and stores facilities will be essential elements of the total package. The final element of air power is C3I support. A future carrier will need to be able to take advantage of the full C3I infrastructure developed for land-based aircraft but will be able to forward deploy the operational aircraft control centre without reliance on any other form of strategic lift. Furthermore the carrier’s comprehensive communications suite will remain in constant contact with higher command, and there will be no requirement for the additional protection required by a temporary shore-based C3I facility.

The unpredictable nature of future crisis, the desire of the Government to use UK military capability as ‘a force for good in the world’ and the consequent adoption of Joint, flexible military formations present a vastly different strategic environment from that of 1966. The broad utility of aircraft carriers would appear indispensable in the post-Cold War-era yet the financial pressures of a modern democracy require the procurement of CVF to be balanced against other conflicting demands on public money. Clearly the procurement of CVF is as much dependent on the ability to produce a potent military capability at an affordable price with demonstrable benefit to the UK industrial base as it is to the currently perceived future strategic environment.

Essential attributes for CVF

On the basis of the doctrinal analysis above, it is clear that the CVF will have utility in a very broad range of missions provided it is carrying aircraft appropriate to the operation. Clearly single role aircraft with utility in one mission type are inappropriate to the carrier’s air group since the ship would be unable to deploy sufficient aircraft of each type to be militarily effective in all roles. In the case of fixed wing combat aircraft, a multirole concept is entirely feasible and in the time frame of CVF it should be possible to procure combat aircraft that are both capable fighters and effective ground attack aircraft. Indeed the Sea Harrier evolved a ‘swing-role’ capability when deployed in the Adriatic, launching with a mix of air-to-air and air-to-ground weapons and responding to both Deny Flight (fighter) and Deliberate Force (ground attack) tasking in a single sortie. This concept will need to be mirrored in the next generation of carrier compatible fixed wing combat aircraft.

CVF will also offer the opportunity to deploy a range of helicopters. Currently, the Invincible-class embark helicopters for ASW and AEW purposes and it is likely that CVF will need similar aircraft to fulfil these roles if it is to be capable of providing the full utility identified in the doctrinal analysis above. However, the roles and missions anticipated for CVF may make Attack and Support helicopters more appropriate aircraft to the carrier’s air group for some operations. CVF will thus need to be able to embark, support and operate a range of different helicopter types as dictated by operational circumstances.

This concept is not new and has been described as a ‘golf bag’ approach to the carrier air group mix. Thus, rather than have a specific, separately identified and procured, air group exclusively attached to the CVF, the ship should provide the flexible air base for whichever aircraft are required in theatre as dictated by operational circumstances. Of foremost importance in CVF design will be attributes that contribute to the generation of combat air power, or sortie generation. Secondly, Survivability and the Combat system which allow the aircraft to be tasked and controlled effectively from a survivable platform. Thirdly, the less glamorous, but nonetheless essential, capabilities that allow the carrier to be available and sustainable for the envisaged operations. Finally, affordability, the difficult task of acquiring and maintaining a capability to deliver air power within the limited financial resources available. This translates into a floating airfield able to deliver decisive air power whenever and wherever required by UK defence policy.

Taking these elements in turn: Sortie Generation.

A criticism of the Invincible-class and indeed any small carrier is that they carry insufficient aircraft to be militarily decisive. CVF is likely to carry more aircraft than Invincible if it is procured, but determining how many aircraft will provide decisive military capability is problematic given the uncertainties of future conflict and scale of contribution that may be made by other Allied aircraft. During CVF concept studies several attempts to quantify the ideal CVF air group were attempted. It appears that 30-40 combat fixed wing aircraft would provide credible capability in most foreseeable scenarios but this is heavily dependent on the assumptions made with regard to enemy order of battle, Allied contribution, aircraft effectiveness etc. Given the uncertainty of future conflict it would seem that the more aircraft the ship can deploy the better.

However, there are practical limits to the size of ship the UK could build and support. The principal limitations are the capacity of the remaining shipbuilding facilities within the UK and the size constraints imposed by existing support facilities in Portsmouth and Devonport. Whilst it may prove cost effective to make minor modifications to these existing facilities, a ship greater than 40-50,000 tonnes would require disproportionate investment in build and support infrastructure. Thus, the UK is essentially restricted to a ship in the order of 40,000 tonnes and capable of deploying 40 or so aircraft. Aircraft capacity itself is a confusing term. For CVF there are three measures of aircraft capacity:

– Design Capacity; the number of aircraft the ship is designed to support with full accommodation, air weapon, aviation fuel and other facilities.

– Hangar Capacity; the number of aircraft that can be stowed with sufficient space for maintenance activities within the hangar. This is in the order of two thirds design capacity, thus a ship with a design aircraft complement of 40 aircraft should be expected to stow around 26 in the hangar.

– Operational Overload Capacity; the maximum number of aircraft that could be embarked if operational circumstances required. In this case the hangar would be cram-stowed and all available deck space would be used to park additional aircraft in a manner akin to that used when Invincible deployed in the Falklands conflict. Thus a ship with a design aircraft complement of 40 aircraft could be expected to deploy a mix of over 50 helicopters and combat aircraft in operational overload, although the exact number would be subject to the detailed hangar and flight deck design.

The ability to deploy 40 or more combat aircraft in CVF represents a significant investment in carrier based air power when compared to the current capability in the Invincible-class carriers with their eight Sea Harriers. Also, as the overall requirement for UK offensive air power is unlikely to increase, the acquisition of CVF would herald a shift in capability from land-based to carrier-based air power. Although the procurement of CVF is still some 12 years away, it is difficult to imagine how such a major increase in capability could be achieved within the Fleet Air Arm. Despite the obvious attraction of a larger, more capable Fleet Air Arm to proponents of carrier-based air power, a more practical, perhaps more palatable and certainly more Joint solution is to build on the recent operational experience of embarking RAF Harriers alongside the Sea Harriers in the Invincible-class. In the long term, the aim would be to acquire a common, carrier compatible aircraft to replace both the Royal Navy’s Sea Harriers and the RAF’s Harrier GR7s. The opportunity would then exist to create a truly joint force equally capable of deploying in the CVF or, if operationally appropriate, to a suitable airfield ashore. Undoubtedly there are significant differences in the manner in which the Royal Navy and RAF currently operate their aircraft and, if the Joint Force concept is to succeed, every effort must be made to resolve these differences and establish common ‘best practice’ before the CVF enters service. Increased alignment of the Sea Harrier and Harrier GR7 communities offers the perfect opportunity to establish common operating and support procedures over the next 12 years.

Even with an air group of 40-50 aircraft the CVF’s resources are limited and all means of maximising the combat power available must be developed: To this end, operating from deck rather than airborne alert preserves aircraft and allows resources to be brought to bear when they are most needed. Some of the operational analysis conducted in CVF concept studies indicated that deck alert is up to five times more efficient than airborne alert and even the most pessimistic assessment gives a 3:1 advantage for aircraft held on deck. Inevitably there are key enabling factors to the concept:

– The ability to generate sufficient warning time for the aircraft to be launched, transit to the engagement area, and conduct the mission before the attacker gains his objective. In air defence this would demand a high quality Airborne Early Warning (AEW) capability.

– The next element in the equation is efficient carrier deck design. Clearly there must be room to safely park the required number of armed aircraft for the expected mission. These same aircraft must be able to launch within the allotted warning time – normally within five minutes. This implies the runway/ski jump or catapult launching system must be readily available to the alert aircraft.

– The final and perhaps surprisingly, least critical element of the equation is the aircraft transit speed. It is generally least critical because the distances involved are relatively small for a supersonic aircraft and thus the operational capability of the aircraft once in the engagement area becomes the more important driver.

To sustain the capability it will also be necessary to minimise the ‘down time’ for each aircraft once it recovers from a mission. Here, the ‘pit stop’ approach to aircraft servicing, a concept borrowed from Formula One motor racing, will increase efficiency. Obviously fuel and weapons are key replenishment items but an autonomic system that informed the maintenance organisation of aircraft unserviceabilities before the aircraft recovered would minimise the time on deck necessary to repair or replace the faulty components. Or, in the worst case, it would allow a replacement aircraft to be brought in to the programme and the unserviceable plane moved directly to the hangar on recovery. With innovations like this it may well be that the limitation on sortie generation will be pilot availability or pilot fatigue.

The next issue will be sustaining this capability over time. Clearly the type and number of air weapons carried will be central to the sustainability of the air group, and aircraft maintenance facilities will also play a key part, but with a concept that calls for tailored air groups and different aircraft types being embarked as required, it will be necessary to provide flexible magazine, workshop and stores support. A modular approach, perhaps based on standard containers, may offer advantages in this regard providing the ship is designed with these concepts in mind from the outset.

Air Group Composition will also be a driver of the CVF’s ability to generate aircraft sorties. In particular, mixed helicopter and fixed wing operations can cause a significant degradation of flight deck efficiency unless fully considered during the design process. Ideally there should be separate operating areas for rotary and fixed wing aircraft although this may prove challenging in CTOL or Short Take Off But Arrested Recovery (STOBAR) ships which require most of the available deck area for the fixed wing activity. The requirement to tailor the air group for each mission, an inescapable consequence of the unpredictable nature of future missions, will also complicate the design since the proportion of rotary wing aircraft in the air group may vary.

A fundamental element of aircraft sortie generation is the type of fixed wing aircraft CVF will be required to operate. There are three generic types of carrier aircraft and each have an associated ship design: Firstly, CTOL aircraft which launch with catapult assistance and recover to an angled deck and arrester wires. This is the traditional concept of aircraft carriers, is practised in the very impressive American nuclear powered carriers, and is the system selected for the new French carrier Charles de Gaulle. The advantage of this approach is that aircraft launch weight is less critical as the catapult provides additional power to assist the launch of combat aircraft in a very short distance. Similarly, returning aircraft remain in wing-borne flight until the moment of touchdown but are stopped in a very short distance by arrester wires picked up by the aircraft’s tail hook. The advantage of this recovery technique is that a CTOL aircraft is unlikely to need to jettison weapons to achieve a safe landing weight. This is particularly significant in peace support missions when weapons are less likely to be expended than in an operation involving full combat.

However, the penalties of catapult and arrester gear operations are significant: In order to withstand the dynamic loads imparted by the catapult and arrester wires, the aircraft requires considerable structural strengthening compared to a land-based equivalent. This implies an increase to the basic weight of the aircraft limiting the overall capacity to carry fuel and weapons. To an extent, this can be minimized, providing the aircraft is designed from the outset for aircraft carrier operations but, inevitably, some aspects of aircraft performance are likely to be degraded in order to meet the demands of CTOL carrier operations.

Launch rates are restricted by the carrier’s ability to generate catapult power. Traditionally, this is steam in very large quantities. For example, two catapults with a 45 second launch interval would require the same volume of steam as that generated by a nuclear powered attack submarine at full power. In the very large US carriers, with nuclear power systems specifically designed for this purpose, catapult steam is not an issue but in Charles de Gaulle which, for reasons of economy, has adapted submarine reactors to power the ship and catapults, launch interval has been extended to one minute between aircraft and, because of the limited power available, the ship’s top speed is around five knots less than ideal. CVF concept studies identified that the cost of nuclear propulsion for a UK carrier is prohibitive so the provision of catapult steam presents unique technical challenges to the Royal Navy.

There are alternative sources for catapult power and the Electro-Magnetic Aircraft Launching System (EMALS), in particular, offers considerable potential. The related technology is already in use in some mono-rail train systems and some of the more advanced roller-coaster rides, but there are significant challenges in scaling the power levels to that required to launch a 20 tonne aircraft within 100 metres. It is doubtful whether the UK could afford to develop such a system without collaboration with another nation.

The third limitation of CTOL carriers on aircraft sortie generation is flight deck management. Even on the large American carriers, aircraft usually require to park on the angled deck prior to launch, preventing simultaneous recovery. Similarly, recovering aircraft are inevitably required to park in the way of the catapult track preventing simultaneous launch. As a result, CTOL carriers tend to operate in cycles with preplanned launch and recovery ‘windows’. Undoubtedly USN carriers are exceptionally efficient at this type of operation but it is not compatible with the deck launched intercept or deck alert concept of operations and in some cases results in aircraft being launched simply to create deck space to prepare for the next pre-planned activity.

The final limitation with CTOL operations stems from the need to provide tanker aircraft from within the air group. For tactical purposes it may well be desirable to provide air-to air-refuelling tankers to extend the range of combat aircraft on a pre-planned ground attack mission but it is less desirable to dedicate a percentage of the limited air group to the tanking role simply to assist in the safe recovery of combat aircraft. The need stems from the fact that an aircraft approaching the angled deck at speeds around 150 knots has a significant probability of missed approach, particularly at night or in bad weather. Tankers provide an emergency refuelling facility to enable these ‘bolter’ aircraft to conduct further attempts at an arrested landing.

The second generic aircraft type is Short Take Off But Arrested Recovery or STOBAR. This concept has only been successfully operated by the Russian Navy but, theoretically, any aircraft with a good power-to-weight ratio should be capable of this type of carrier operation. The concept relies on the aircraft having sufficient power margin to be able to take off without the aid of a catapult but probably assisted by a ski-jump launch. Recovery is to the traditional angled deck and arrester wires. Clearly many of the same issues apply to this concept as they do to CTOL carriers although the elimination of catapults significantly simplifies the ship design, particularly in non-steam ships. In addition, deck management issues are potentially more critical than in the CTOL case since a STOBAR aircraft will require a longer take off runway than the 100 metres used in a catapult system. The third generic aircraft type is STOVL.

This concept is currently employed by the Harrier and Invincible-class combination. In CVF time scale the only new STOVL aircraft, and the first with supersonic capability, will be a product of the US/UK Joint Strike Fighter programme. If this aircraft development programme is successful, then there will be a credible STOVL aircraft capable of meeting the range of missions required by the next generation of UK carrier based aircraft. STOVL operations offer many advantages:

– Flight operations are less affected by sea state than in a CTOL or STOBAR ship. This is because the STOVL aircraft establishes a hover alongside the ship and can choose the deck area with least motion and await a quiescent period before committing to the final landing. In contrast a CTOL or STOBAR aircraft approaches the landing area at high speed and must attempt to land in precisely the area where the arrester wires are deployed. Thus in a high sea state with considerable deck motion there is an increased likelihood of missed approach.

– A STOVL ship has no catapults, reducing ship complexity, flight deck maintenance and increasing reliability.

– Since a STOVL aircraft is not required to conduct an arrested landing there are concomitant benefits to aircraft weight and the elimination of the need for tanker aircraft.

– STOVL operations imply simpler flight deck management with a greater probability that the launch area can be kept available to aircraft held on a short deck alert prior to launch.

However, STOVL aircraft are limited by the power available and tend to have reduced payload and radius of action compared to CTOL alternatives. Significantly, given the increased prominence of peace support operations, a STOVL aircraft has a very limited ‘bring back’ capability; that is the available power margin severely restricts the amount of fuel and weapons the aircraft can retain if it is to complete a vertical recovery. These limitations may be partially resolved during Joint Strike Fighter development but careful carrier design could also offer significant advantage. For example, if STOVL aircraft were to be operated from a ship with an angled deck it would be possible to offer a running landing to the aircraft and increase the ‘bring back’ payload. In these circumstances the STOVL aircraft would employ much slower approach speeds than a conventional aircraft and thus avoid the need for a full arrested landing and the concomitant airframe structural strengthening.

Thus the choice of fixed wing combat aircraft will have a fundamental effect on the CVF design. However, if the deck-launched intercept concept of operations for air defence is to be viable, then the choice of AEW aircraft must also be considered. For example, if the next generation combat aircraft is a STOVL variant of the Joint Strike Fighter, CVF could be a relatively simple STOVL design. In consequence, the choice of airframe for the next generation AEW aircraft would probably be limited to a helicopter or helicopter derivative (ie., the advanced compound helicopter). But, a helicopter may not be able to fly at sufficient altitude to provide the radar range (and thus warning time) for the fighters to launch, transit and intercept the attacking aircraft before they release their missiles against the force. If, however, the CVF were to incorporate an angled deck, then the choice of AEW aircraft could include the V22 Osprey tilt rotor, with significantly better service ceiling, speed and time on task than currently attainable by a helicopter. The angled deck is necessary since a V22 could not launch via the ski jump (essential to the combat aircraft) but the angle would allow a clear deck run for a rolling take off. Therefore, the decisions on CVF design and which aircraft to procure for the next generation of AEW and carrier compatible fixed wing aircraft must be co-ordinated and considered in a ‘system of systems’ approach.

Combat System and Survivability. The combat system includes all elements of the ship’s fighting ability including navigation, communications, sensors and weapons up to and including the interface with the embarked aircraft but not the aircraft themselves. It is a matter for debate how complex the combat system in a future UK carrier needs to be. It is after all a key element in the survivability of the platform but it is only one element of layered defence which includes the contribution made by the air group, other aircraft, escorts, platform signature control and passive defence measures – the ship itself does not have to be a fortress. As recent operations have demonstrated, finding a carrier is difficult enough – bringing sufficient capable forces to bear to pose a credible threat is an operation that only a handful of nations are capable of achieving.

The focus for the combat system must be the facilities required effectively to task the air group, conduct mission planning and control the air war. In this, full use should be made of the UK’s continuing investment in Intelligence, Surveillance, Targeting And Recognition (1STAR) equipment. Admittedly much of this is designed principally for RAF purposes but since CVF will potentially be operating the same aircraft on the same missions as those flying from ashore, the ship should be capable of exploiting all the information available.

Such facilities will make the carrier an extremely attractive platform for higher command – Task Force, Joint or Combined. Established, reliable communications, comprehensive imagery and intelligence facilities in a fully defended and Nuclear, Biological & Chemically (NBC) protected hull offering relatively high standards of habitability would seem an attractive prospect to most Joint Force Commanders, particularly if the alternative is a tent! Should CVF feasibility studies proceed, such options should be explored but only as an optional addition since the command task is not the primary role focus for the ship. Similarly, concepts such as re-configurable operations centres utilizing flat screen and multi-use display technology, might also add to the flexibility of the platform in the command role.

Clearly, with such a significant element of the UK’s offensive air power embarked in a single ship, the CVF must be a survivable platform. Reducing susceptibility to attack by careful control of platform signature is an obvious means of enhancing the survivability of the CVE Signature control will encompass radar cross section, acoustic, magnetic and infra-red management. The aim will be to limit a potential enemy’s ability to locate, identify and target the CVF specifically. This does not imply a need for ‘stealth’ but positive signature control is required to make it difficult to distinguish the CVF from other vessels or tactical decoys. Given good signature control and the fact that the CVF will generally be at the heart of a force protected from above and under water attack by several defensive layers, the probability that the carrier will be successfully attacked is extremely low. In addition, tactical decisions, particularly the position and routeing of the carrier, and evolving Joint Doctrine should be based on the expected threat levels and ensure that exposure to significant risk is minimised. Nevertheless there are circumstances, particularly when operating under restrictive rules of engagement or perhaps as a result of a maverick style attack, when the CVF could be exposed to direct attack. In these circumstances, the last line of protection will be the carrier’s own suite of self defence weapons and decoys. The extent to which these systems will need to be incorporated in the CVF design is subject to assumptions made about predicted threat levels, concepts of operation and escort policy. However, it is difficult to accept that a ship of this military and political significance will not warrant at least a full suite of decoys (including the surface ship torpedo defence system) and some form of anti-ship missile defence ‘hard kill’ weapon. Naturally affordability will be a key aspect of the equipment finally selected, but even the most sophisticated self-defence missile system is likely to cost less than 1% of the total procurement cost of the ship, arguably a small price compared to the national embarrassment likely to result if CVF were successfully attacked whilst engaged on defence diplomacy or crisis prevention operations.

In the unlikely event that the CVF is successfully attacked, design features that increase tolerance to damage including blast alleviation techniques and fragment protection of mission essential compartments will enhance the survivability of the carrier. Large ships are inherently more survivable than smaller vessels but more can be achieved by careful consideration of compartment layout without incurring additional cost. Other measures, particularly shock protection, will need to be carefully focused at protecting areas essential to the efficient operation of the air group. System redundancy and the avoidance of single point failure will be essential to the fighting efficiency of the ship. The overall aim must be to ensure that the CVF is able to continue flight operations post attack, so that a single strike against the carrier does not eliminate the air group from continued participation in an operation.

Other elements of survivability include damage control and fire-fighting facilities. Traditionally these are manpower intensive activities which could become a complement driver for the CVF in the action state. A compromise will need to be established where technology is used to reduce the reliance on manpower for the routine management of the damage control organisation yet leaving sufficient flexibility in the overall ship’s complement to manage the range of tasks CVF may be required to perform, including the effective control and repair of battle damage.

Returning to the view that weapons of mass destruction are likely to be more widespread in the future, it may be necessary for the CVF to operate in an NBC environment. Targeting a maritime force with NBC weapons is not a trivial task and the first defence will always be to vacate the area should an opponent succeed in delivering such a weapon against the CVF. That said the embarked aircraft may well fly in contaminated areas remote from the ship and efficient cleansing and monitoring systems will be essential if the carrier is to remain an effective fighting unit.

Availability and Sustainability. Of course a carrier’s capability is of no use at all if it is not available when needed. Therefore, minimising the length of time a future carrier spends in maintenance activities is a key area for improvement over our current ships. A support policy based on reliability and condition-based maintenance will reduce the amount of upkeep required compared to the planned maintenance system currently used. Similarly if the required maintenance is conducted in frequent, short bursts the ship will never be unavailable for periods greater than six months and, if required in an emergency, could generally be recovered to the programme more quickly. Such a policy would not require long refits for the upkeep of the vessel which would limit the amount of update that could be achieved during routine maintenance. However, incremental updates are probably more cost-effective and careful consideration of the position of components which are likely to require update during the life of the vessel, for example, elements of the combat system, during the design process will allow later updates to be made more efficiently. Pre-planned equipment removal routes and, again, modular concepts may have advantage.

In operational terms availability might be regarded as the probability that the CVF can be on station when needed. Central to this issue will be the carrier’s speed of deployment and inherent endurance. In a large surface ship speed is a cost driver in the design of the vessel. During the concept study period it was established that a deployment speed of 18 knots will be required if the CVF is to be able to meet the range of military tasks envisaged in the areas of particular significance to the UK. However, the top speed requirement for an aircraft carrier is driven by the need to provide wind over the flight deck to assist in the launch and recovery of aircraft. This requirement, together with a need to maintain station within a maritime force, which may be transiting down wind, drives the top speed requirement to a minimum of 28 knots. This increases to 31 knots for CTOL ships since the launch and recovery of conventional aircraft tends to take longer than a STOVL equivalent, increasing the station keeping problem for the carrier. The endurance of a maritime force is traditionally extended by replenishment at sea. However, operating in littoral waters may make replenishment operations more difficult, particularly if there is limited sea room. Since the littoral is perceived as the most likely operating area for the CVF it will be advantageous to minimise the dependence on underway replenishment as far as practicable. Thus it should be possible to design the platform with high availability in both operational and maintenance terms. However, the availability of the crew must also be matched to the vessel without imposing undue hardship or contravening the harmony objectives which are applied across the Royal Navy. Innovative manning and training techniques may therefore be required to generate the necessary manpower without significantly increasing overall manning levels and thus the through life cost of CVF.

Affordability is probably the key issue in deciding whether the UK will invest in a new generation of aircraft carriers. The RN is not in the market for very impressive but extremely expensive carriers like the USN Nimitz-class or even the more modest but nevertheless very costly French nuclear powered carrier Charles de Gaulle. Clearly these are capable ships but at a price the UK cannot afford. The RN must therefore identify a way to project air power in a more affordable manner but without reducing the effectiveness of the carrier and its air group to a level where it can no longer deliver decisive military capability.

Concept studies have explored various ways in which large ships could be built at an affordable price. The first of these is the so called ‘big empty ship’ philosophy. In the past it has always been argued, and thus current cost models are based on the assumption, that ship cost is directly related to displacement. With modem ship building methods this is no longer true; steel work is relatively inexpensive, the real cost driver in a complex warship is compartment packing density. This is entirely logical if the working constraints of fitting complex machinery and electronics in a confined area are considered. The big empty ship approach provides high volume, less constraints on fitting out and is of course, more readily suited to modular concepts and update through life. Commercial welding and other techniques will allow this high volume hull to be produced cheaply with similar capability to the full mil-spec alternative. Secondly, allowing industry to use best commercial practice when it is militarily acceptable (such issues as accommodation, machinery control, etc.) will also generate considerable procurement savings. Utilising sub-systems that have been developed for other purposes, particularly in the combat and propulsion areas, will reduce cost and risk. The aim must be to develop only technologies that are CVF specific and for which no acceptable alternative currently exists. Thirdly, the use of modem computer aided design tools and electronic data management, coupled with virtual reality and simulation–based design methodologies suggests that it is increasingly possible to build the ship ‘right first time’. More traditional design tools often resulted in a need to modify the ship as it was being built with considerable elements of rework which added significantly to the cost of production. Some estimates suggest that up to 30% of the procurement cost of a traditionally designed warship is attributable to the effort required to ‘correct’ the design during the build process. For CVF, full utilisation of computer based design tools offers considerable scope for containing the cost of the vessel.

Other cost controls have already been alluded to; focus on primary role requirements and only providing other capabilities if it can be proved that CVF is the most cost-effective host platform. In this, higher command facilities are a classic example, but force electronic warfare and other force weapon systems should be subject to similar scrutiny. Finally, the ‘golf bag’ approach to the air group encourages a mind-set that does not think of a pre-formed carrier air group but regards the carrier as a floating airfield able to support as wide a variety of UK aircraft as possible, many of which may have been procured with different deployment concepts in mind.

Conclusions

The future strategic environment and the perceived role for UK Armed Forces within that setting suggest that a carrier capability will be an essential element of the UK’s arsenal. However, the CVF must compete for funding with other defence priorities and other claims on the public purse. The challenge is to procure an affordable but effective military capability relevant to the roles and missions for UK forces emerging from the current Strategic Defence Review. The issues discussed in this article suggest that this is an achievable goal but only if some of the more traditional concepts of aircraft carrier operations, procurement and support are abandoned. Realising the full benefits of a Joint, tailored air group, of modern ship design and construction and of innovative support and manning concepts poses considerable challenge over the next decade but the prize is deployable UK air power, wherever and whenever required by political and diplomatic pressures. In the uncertain future, no other platform or weapon system will be as relevant to projecting UK influence around the world as will an aircraft carrier, providing it is a truly, ‘Joint Defence Asset’.