'Cats and Traps': Launching the Carrier Debate in the Right Direction?

Media debate on the UK's carrier programme is focusing on the jets, rather than the ships they land on. Central to this discussion is 'cats and traps', the launch and recovery system, which drives the choice of aircraft. Critics who say that this will cost too much overlook the long-term strategic value it will add.

By Dr Lee Willett, Senior Research Fellow, Maritime Studies, RUSI

Ahead of the 1998 Strategic Defence Review (SDR), The Economist argued that the United Kingdom (UK)'s on-going debate about aircraft carriers would provoke the 'biggest row of all' in the forthcoming defence review, simply because '[t]he possession, or not, of aircraft carriers - more than any other weapon - says a lot about a country's self-image.'[1] Eighteen months on from the October 2010 Strategic Defence and Security Review (SDSR), and as serious debate develops about decisions to be made in the (expected) 2015 defence review, this argument still holds true.

Carriers and SDSR

The carrier question was pivotal both in the debates leading up to the SDSR and in the Review's conclusions and consequences. Intending to generate an adaptable capability based around two ships and balanced with the rest of the UK force structure, SDSR's principal points were:

Strategic Rationale

  • An aircraft carrier capability provides a range of political and military options, as a complement or alternative to ground engagements, to respond to state and non-state threats.
  • A carrier capability supports the strategic requirement to project air power where and when required in support of UK interests, without the need for reliance on land bases.
  • Although the UK envisaged few circumstances in the short-term where deploying sea-based air power would be essential, it acknowledged the need for the longer-term political flexibility provided by carriers to mitigate against dependency on permission of other states for access, basing and overflight (ABO) rights.

Programme Decisions

  • The construction of two carriers - HMSs Queen Elizabeth and Prince of Wales - with one to become operational and the other to be placed in extended readiness (able to return to service if required). The in-service date of the operational carrier was revised to around 2020, from original dates for two ships (as announced in December 2008) of 2016 and 2018.
  • To fit catapults and arrester gear ('cats and traps') to the Prince of Wales to enable interoperability with other navies, their aircraft and ships.
  • The purchase of the Carrier Variant (CV) of the F-35C Lighting II Joint Strike Fighter (JSF). CV, with longer range and the ability to carry internally a greater range of weapons to give greater power projection capability, also uses 'cats and traps' for launch and recovery. The decision comes after the UK considered both variants before the Short Take Off and Vertical Landing (STOVL), or F-35B, version was selected in September 2002 and approved in July 2006. Improved commonality across the fast jet fleet through operating one aircraft type at sea and ashore is estimated to reduce through-life costs by around 25 per cent.
  • Numbers of aircraft - both procured overall and embarked at sea - are to be reduced, as the UK no longer requires the scale of strike capability previously planned. The UK planned originally to buy 138 in total, but reports have suggested this number will be cut perhaps to just 50. The intention is to embark 12 fast jets routinely for operations on the single carrier, while retaining the capacity to deploy up to the 36 previously planned.

In recent weeks, reports have suggested the Government is considering a switch to STOVL or F-35 B because potential cost increases in 'cats and traps' are making the CV (F-35 C) option unaffordable in the short-term, especially given the on-going financial challenges. While the SDSR states the aim to seek 'in-built' flexibility to adapt the carriers' capabilities over their 50-year life, in the current debate some significant issues - particularly relating to this requirement for flexibility - are being overlooked.

Should the UK Bring Both Carriers into Service?

Possessing two operational carriers can offer strategic advantage. Minister for International Security Gerald Howarth MP, hinting that the Government hoped to 'look again' at and 'recover' in the 2015 defence review the decision to deploy only one operational carrier, stated that bringing both ships into service would provide 'continuous at-sea capability'.[2]

Recent operational history has highlighted the role of carrier strike operations in both Afghanistan and Libya. With only one operational carrier, the UK would have been unable to conduct concurrent operations in both theatres. One carrier also may not be sufficient to enable the UK to cover areas of interest which include the Indian Ocean, the Persian Gulf, the Mediterranean and the North and South Atlantic. With only one carrier, routine maintenance and refit may result in the UK having - at times - no capability at all.

Should the UK Fit One - or Both - Carriers with 'Cats and Traps'?

Much of the current debate focuses on potential delays and cost increases in buying and installing 'cats and traps'. Recent press reports suggest that reverting to F-35 B, with the removal of the requirement for a 'cats and traps' fit, may result in savings which would enable the UK to bring both carriers into service. At this stage, there is no evidence of any formal discussion of converting the second carrier to 'cats and traps', or of any potential costs. However, if the UK is able to consider bringing both ships into operational service at some point, should financial circumstances allow: having both fitted with 'cats and traps' would enable the capability to be available continuously.

'Cats and traps' also enable interoperability with the US Navy which is providing the launch and recovery system the UK will use. For its next generation carriers, the CVN-21 class, the US is developing a new 'cats and traps' system, comprising the Electro-Magnetic Aircraft Launch System (EMALS) and Advanced Arrestor Gear (AAG) technologies. The first-of-class, the USS Gerald R. Ford (CVN-78), is already in build, with the system being installed as the ship is constructed. According to Congressional testimony, the ship is on schedule to enter into service in 2015.[3] This is earlier than the planned in-service date for Prince of Wales. As the Ford-class carriers are expected to be in service for most of the rest of this century, installing 'cats and traps' would give the UK carriers interoperability with US Navy (USN) for as long as is required.[4]

Interoperability and Future-Proofing - Today and Tomorrow

Given SDSR's stated intent to maximise the carriers' in-built flexibility, 'cats and traps' offer advantages for current and future capability, innovation and interoperability.

First, there has been regular discussion as to whether the UK has a 'Plan B' should JSF be delayed or even cancelled. 'Cats and traps' provides a 'Plan B' by enabling the UK to consider other aircraft options. If there is a gap between the ships entering service and the availability of an aircraft (should either STOVL or CV be delayed), installing 'cats and traps' would allow the UK to consider purchasing or leasing French Rafale aircraft or US F/A-18 Hornets to bridge the gap. These aircraft are both launched and recovered by 'cats and traps'. However, there is no other STOVL aircraft which could fill the F35B's place. The Hornet option is an interesting example. A number of Royal Navy pilots already are flying Hornets in training and combat from US carriers. Moreover, Hornets are also already interoperable with the French Navy's aircraft carrier Charles de Gaulle: C variants have flown from the French carrier on exercise in the Eastern Atlantic. The USN has already developed tanking and electronic warfare variants of the Hornet which the UK could use if required. An interim solution of either Hornets or Rafales would also enable the UK to embark aircraft on US and French carriers before its own ships arrive and to use these aircraft to help de-risk its 'cats and traps' fit. The Hornets are scheduled to be in service until 2036, so purchasing Hornets also gives the UK greater choice in when to start buying the Carrier Variant, as well as offering a longer-term option should JSF not work out. Moreover, an interim solution like Hornet would negate the political debate about 'ships with no planes'.

Secondly, 'cats and traps' will also pre-fit the carriers for future air capability developments beyond JSF. Much discussion of 'sixth generation' combat air vehicles focuses on the development of Unmanned Aerial Vehicles (UAVs). At present, some of the principal UAV programmes the US Navy is developing for carrier-based combat operations would be launched by 'cats and traps'. These include the X-47B Pegasus and the Sea Avenger.

A 'cats and traps' fit would also strategically appeal to the United States by providing an extra carrier deck to fly from. Richard Scott has argued that carrier interoperability is as strategically crucial to the US-UK defence relationship as the existing relationships on nuclear weapons and submarines.[5] With defence co-operation also a key factor in the UK Government's effort to improving strategic relations with France, so the ability to cross-deck with French aircraft and carriers would be an important contributor. Media reports suggest that the Carrier Variant is too heavy to land on the Charles de Gaulle and that the UK's own carriers will not be configured to carry French aircraft. However, as the aircraft and ship programmes are still being developed and as discussions between the navies are on-going, it seems unlikely that conclusive positions have been reached on these issues. At a time of enduring financial and strategic challenges, and with a wider government emphasis on strategic partnerships, the links between the three major navies would be strengthened considerably if all three possessed the same core carrier capability.

Which Carries Less Risk: CV or STOVL?

The F-35 B, or STOVL, remains potentially a very capable aircraft which meets UK requirements. The STOVL concept also continues to offer a unique benefit, with its vertical take-off and landing capability enabling aircraft to operate for example when available basing infrastructure may not support conventional take-off and landing.

However, the prominent press discussion surrounding a potential reversion to STOVL has not highlighted a number of development, production and operational risks and costs which remain, including:

  • limits on aircraft's vertical landing weight, forcing the UK to develop a rolling landing concept for aircraft still carrying a certain weight of weapons and/or fuel;
  • the less-capable STOVL will reduce the flexibility in the UK's carrier capability. Both aircraft may meet UK requirements, but the greater range and payload flexibility offered by the Carrier Variant improve the flexibility mandated by SDSR;
  • While likely final unit costs of both aircraft remain uncertain at this stage, reports suggest that buying the required number of additional STOVL aircraft to make up for the capability shortfall between the two variants would cost an extra £2.4 billion in total, with 136 STOVL required instead of 97 Carrier Variant. Moreover, the SDSR assessed through-life support costs for STOVL to be 25 per cent higher than for CV.
  • Whether reverting back to STOVL will incur any additional costs, for example if the CV decision had precipitated ship design changes which would have removed the ability to operate STOVL

The Daily Telegraph reported that a leaked operational analysis paper produced by the MoD's Defence Science and Technology Laboratory (DSTL) demonstrated that the Carrier Variant is 'more effective ... [and] provides a more robust capability ... in almost all cases' when considering the respective contributions of both variants to the scenarios considered in the paper.  As interoperability is an important factor in the carrier concept, it is worth noting that, although a STOVL aircraft can be flown off the deck of a carrier fitted with 'cats and traps', this is not something which the UK has done before with the US, and the way the US conducts carrier flight operations (using high-intensity sortie rates conducted over 12-hour period rotations) raises the question as to whether a STOVL aircraft could be operated from a US carrier deck without interrupting the flow of the ship's conventional strike operations.

Because JSF arguably is the only current 'fifth generation' aircraft, attempting such a conceptual leap forward in design, technology, build, testing, operation and support will inevitably be challenging. As a result, there remains risk of further problems, cost growth and time slip in all three variants (the third being the F35A Conventional Take-Off and Landing aircraft, scheduled to enter into service with the US Air Force). The US Government Accountability Office (GAO) has highlighted specifically the risk in conducting simultaneous development, testing and production.[6] For CV, one of the most prominent recent challenges has been the tailhook, which has been failing to catch the arrester wire in certain tests. While a re-design and testing of the hook still needs to be completed, aircraft manufacturer Lockheed Martin stated in January that the issue is 'fairly straight forward and isolated to the hook itself ...  It doesn't have secondary effects going into the rest of the airplane', and the testing of the new hook is expected to begin in the second quarter of 2012.

Some of the current press debate seems to imply that the risks are greater in the Carrier Variant than in STOVL. The development challenges in both variants must not be understated, and there may of course be risks in both which are specific to UK programme requirements. However, it must be noted that -- while a US Department of Defense-imposed two-year probation period on STOVL was lifted a year early in January 2012 -- US Defense Secretary Leon Panetta acknowledged that STOVL had still only reached 'the kind of performance and maturity that is in line with the other two variants'.[7] In addition, the GAO reported that several of the fixes put in place are 'temporary and untested', adding that the effect of the fixes 'in some cases, will not be known for years'.[8] This view was supported by the findings of the DSTL paper discussed in the Daily Telegraph, where it referred to 'considerable technical risks' which still exist in the STOVL programme.

Cost and Strategic Risk

The carrier issue continues to generate heated debate. This has been evident in how the debate about the costs of the different variants as well as the installation of 'cats and traps' has been portrayed in the media. A number of articles claim that conversion costs of perhaps £2 billion are too expensive within the SDSR, with press sources quoting "Whitehall officials" as saying that there is 'every likelihood the costs will continue to rise'. Yet, according to statements from senior US officials, such estimates are inaccurate. The Daily Telegraph reported that US Assistant Secretary of the Navy for Research, Development and Acquisition Sean J Stackley wrote to Peter Luff, UK Minister for Defence Equipment and Support, to inform the UK that 'cats and traps' equipment would cost £458 million to procure and that the US would underwrite any equipment and cost risk (with the Telegraph contending that defence experts estimate an additional £400 million to fit the equipment). While the US has its own budget constraints and while there may be some development costs which would be specific to the UK, this total of under £860 million nevertheless remains significantly smaller than figures mentioned in the press, where there has been no explanation of what the additional £1 billion might include. Also, fitting one or both ships with 'cats and traps' at this stage offers potentially more cost savings than deciding to do so later should this be required.

While Secretary Stackley's letter reaffirmed the US commitment to supporting the UK programme, The Daily Telegraph quoted another Whitehall source stating that the US '[wants] to ensure that the information the British Government is working from is accurate because currently that is quite clearly not the case'. The direct intervention of the US Government highlights the significance of the issue to the US, particularly in the context of the future of JSF and the question of interoperability. Given the impact any UK decisions may have on the US, this raises questions about whether the US is providing input into the UK decision-making process.

The Need to Opt for Long-Term Strategic Value, Not Short-Term Cost-Cutting

The UK carrier capability requirement is to deliver deployable aviation in support of government policy. This leaves policy-makers with a number of options: delivering two STOVL-capable carriers; bringing into service an aircraft type which can operate with one UK 'cats and traps' carrier and with any other compatible aircraft carrier; or bringing in two 'cats and traps' carriers, thereby maximising through-life operational flexibility.

The MoD has said little publicly, other than to state that no decisions on the variant have been made, and that it is continuing to assess a number of programme aspects. While generating a conventional carrier capability is acknowledged by some as 'a step change' to 'an altogether new carrier-borne capability' which brings significant short-term costs and risks, the whole point of the SDSR's original decision to switch variants was to deliver improved capability, flexibility and interoperability.[9] The Carrier Variant's improved capability - and, in particular, the interoperability enabled through the required 'cats and traps' fit - will generate greater long-term strategic utility, flexibility and value.

The choice facing the UK is not so much about jets as it is about whether the UK should opt for the longer-term strategic value provided by fitting 'cats and traps' to one or both carriers, or whether it should opt for possible short-term cost savings, which itself is subject to debate. Of course, any additional investment in new equipment for either carrier will have consequences for the balance of investment across the defence budget, but the question of through-life flexibility remains. 'Cats and traps' can both de-risk for today and future-proof for tomorrow. The F-35 B or STOVL will inhibit the very flexibility and political choice that is essential for the UK's carrier capability.

The views expressed here are the author's own and do not necessarily reflect those of RUSI.


 (A fuller bibliography downloadable here)

[1] The Economist, 31 January 1998, p.32.

[2] Gerald Howarth (Minister for International Security Strategy), in 'Navy May Get Two Carriers After All', The Daily Telegraph, 23 August 2011, p.12.

[3] Statement before the House Armed Services Committee Subcommittee on Seapower and Projection Forces on Navy Shipbuilding Acquisition Programs and Budget Requirements of the Navy's Shipbuilding and Construction Plan, 29 March 2012. p.4.

[4] Ibid., p.3.

[5] Richard Scott, 'Lining up the Approach: UK Eyes a New Special Relationship to Generate Future Carrier Capability', in Jane's Navy International, December 2011.

[6] United States Government Accountability Office (GAO). 'Joint Strike Fighter: Restructuring Added Resources and Reduced Risk, but Concurrency is Still a Major Concern'. Testimony before the Subcommittee on Tactical Air and Land Forces, Committee on Armed Services, House of Representatives. GAO-12-525T. 20 March 2012. Executive Summary & pp.1, 7 & 17.

[7] Leon Panetta (Secretary for Defense). Cited in Amy Butler, 'Panetta Lifts F-35B Probation', Aviation Week, 23 January 2012.

[8] GAO. 'Joint Strike Fighter:', op. cit., p.10.

[9] Richard Scott, Op. Cit.

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