STOVL or CV F-35?

The generally favourable experience of STOVL carrier operations over the previous 15 years had by the mid-1990's brought the RN close to prescribing a STOVL solution for the then Sea Harrier Replacement (subsequently incarnated as the Future Carrier Borne Aircraft and now Joint Combat Aircraft).  The service was an avowed proponent of STOVL on account of, amongst other things: better sortie-generation rates; reduced aircraft impact on overall platform size and cost; and the ability to operate in higher sea states. 

Yet in 2000 these assumptions began to be revisited.  For one thing, the size of the carrier had been driven up quite significantly to accommodate and operate an air wing sufficient to achieve desired sortie-generation rates.  As a result, CVF was likely to displace around 55,000 tons regardless of whether it operated a STOVL or CV air group.  At this size, sea state impacts less on aircraft operating limits.  Industry sources suggested that CVF should be able to conduct operations in conditions up to Sea State 6.  A CV-configured carrier would enable cross-deck interoperability with the USN and the French Navy, and open the way to a more capable MASC solution, nullifying the misalignment between the JSF downselection and the MASC programme.  By mid-2002 the Royal Navy increasingly saw the CV version as being cheaper, flying further and carrying more.  "The requirement is value for money," said Commander Ron Finlayson, in charge of the Royal Navy's surface ship capabilities. "We plan to run these ships for 50 years and in cooperation with other navies. We wouldn't expect to regularly run U.S. Navy F/A-18s or French Rafale's off them, but do we want to be locked into a configuration that only STOVL aircraft can use?".  

Although the UK firmly committed to JSF for meeting its JCA requirement in January 2001, no decision was made at that time between the two carrier capable variants.  Instead the Defence Procurement Agency (DPA) put in to place a mechanism to decide whether the UK should opt for the short take-off and vertical landing (STOVL) variant, hitherto the UK's planning assumption, or the Carrier Variant JSF (the latter actually designated as the "CV" variant because the land-based JSF variant for the US Air Force is confusingly designated the "CTOL" variant!).  One factor for this indecision was the fact that the USA was considering abandoning the technically risky JSF STOVL variant, and concentrating on just the CV and CTOL variants, another was the greater than expected difference in performance between the STOVL and CV variants

The MoD's difficulty in coming to a conclusion on JCA in part reflected the continuing uncertainties about the relative cost and performance of the F-35 STOVL (F-35B) and CV (F-35C) variants, their impact on the carrier design, and their implications for through-life cost of ownership. It also had to take into account the results of operational analysis examining the UK's overall future offensive air capability, and 'softer' issues such as the concept of operations.

"The decision to be made between the STOVL and [CV] variants will be a difficult one," said Wing Cdr Green said RAF Wing Cdr Mark Green of the Joint Combat Aircraft integrated project team (JCA IPT). "They are being viewed as equal competitors. Our final decision will be informed by the results of the current concept demonstration phase, study work to examine the UK's future offensive air capability, and a range of 'softer' issues such as our concept of operations."  

"It's a very complex decision-making matrix, and the arguments for and against are very tight," said one senior maritime aviator. "It goes without saying that the CV variant gives us access to more target sets, will have a longer range and a greater 'bring back' capability, but it will undoubtedly come at greater cost. I suspect it will ultimately be a balance of investment decision."

But by mid-2002 it was being reported (e.g. by JDW) that the higher echelons of the RAF -  the service that will 'own' the aircraft and thus a very significant "player" in the decision process - was firmly inclined towards STOVL.  Officially this was in part because of the greater flexibility of deployment, but also because of the lower training penalty needed to keep those predominantly RAF-manned JCA squadrons carrier qualified.  And the advocates of STOVL apparently had some strong arguments, for example Major Andrew G. Shorter, USMC states in article published in the September 2003 edition of the USNI Proceedings:

Studies compared the effectiveness of conventional take-off and landing (CTOL) and V/STOL aircraft at sea.  One study, conducted by the American Institute of Aeronautics and Astronautics (AIAA) in 1980, concluded that V/STOL aircraft provide better mission performance at sea with fewer aircraft.  This stems from the V/STOL's ability to generate a greater number of sorties for a given time period, primarily because it is unconstrained by the normal deck cycles of CTOL aircraft. The AIAA study points out that "the air platform from which V/STOL operates can be smaller than today's large deck carrier. The support costs, including logistics, maintenance, manpower, et al. are reduced for both the aircraft and the ship." This concept sets the stage for reducing the large overhead normally associated with sea-based tactical aviation to the point where it can be considered viable on many more seagoing platforms.

The STOVL JSF greatly reduces the training and currency requirement for fixed-wing operations afloat. This increases commensurately its ability to be adopted and employed jointly as the Air Force is no longer excluded from non-land-based operations. With the large power margins, enhanced stability control, and pilot augmentation systems the STOVL JSF will incorporate, safe and efficient landings at sea will become easy and straightforward. This should lead to streamlined training and extended currency limits—so much so that non-naval-trained pilots could become ship-qualified in just a few days. Consider the flexibility of being able to jointly sea base all of the services' primary tactical air assets, not only in the context of the tenets mentioned earlier, but also in the form of indefinite sustainment for the force structure. The STOVL JSF squadrons from any service, with minimal effort, could provide forces for surged or sustained sea-based maritime operations—a force planner's dream.

Fewer aircraft require less hangar space, fewer maintenance and support personnel, and for STOVLs, fewer ship systems to support them and a much smaller air department. STOVLs require 30% less deck space for operations, which leads to increased operating efficiencies.  Those efficiencies allow generation of more sorties given equal mission performance. For example, STOVL aircraft can generate 30% more sorties than CTOL aircraft for targets out to 400 nautical miles, and 15% more for ranges to 700 nautical miles.  The affordable combination of multiple missions within one hull design can become a reality based on our emerging technology.

However some people started to challenge the RAF's view of the steep gradient of the additional training required for JSF CV vis-a-vis STOVL, arguing that high-fidelity simulators, the JSF's advanced flight-control system, and modern auto-land facilities would make carrier landings far less challenging than hitherto assumed.  Indeed, it was pointed out that back in the 1960's and 1970's pilots were safely making their first 'trap' on RN fleet carriers with only minimal shore based training as specialist training carriers had disappeared in the 1950's and suitable simulators simply didn't then exist, indeed the 1965 Defence White Paper envisaged RAF F-4 Phantom squadrons operating from RN carriers if required!   Also, assumptions on the cost differential between a STOVL and a CV (CTOL) carrier were proving overly pessimistic.  Early Assessment Phase 2 deliverables from both contractor teams suggested a differential of between £80 million and £100 million per ship at build, significantly less than the £200 million previously speculated. 

MoD and industry sources also quietly suggested that the RAF was actually anxious that JCA should not threaten Eurofighter Tranche 3, nor dilute its aspirations for the Future Offensive Air System (FOAS).  The RAF was worried that the long range (800nm) F-35C would be regarded by both the MOD and Treasury as having sufficient capabilities to fulfil the FOAS manned role, and thus funding for a separate, dedicated, non-naval, fast jet aircraft specifically procured for FOAS would be cut.  Selecting the shorter range STOVL F-35B for JCA avoided this problem.

Entering the increasingly heated and closely balanced debate, UK industry now voiced its support for selecting the STOVL variant of the F-35 for FJCA.  Rolls-Royce, as developer and supplier of the STOVL variant's shaft-driven lift fan, stood to gain far greater industrial benefit from a decision in favour of STOVL, which would in turn bring UK political weight to bear on the US Department of Defense's commitment to the USMC STOVL off-take.  BAE Systems sources also indicated that, from a programmatic and long-term business outlook, a decision in favour of STOVL would be favoured by it.

The MoD's Investment Approvals Board (IAB) re-convened on 12 August 2002 to consider the down-selection of the STOVL or CV variant of JSF for JCA, after being unable to reach a decision in a previous meeting in early July.  Based on overall affordability, backed by a strong industrial advocacy, the STOVL variant of JSF was considered to have the edge on balance.  The Defence Procurement Minister, Lord Bach, finally announced on 30 September 2002 the selection of the short take-off and vertical landing (STOVL) variant of the Lockheed Martin F-35 Joint Strike Fighter as the JCA.  He said that choosing the STOVL variant of JSF would build on the RAF and RN's "unique and valuable knowledge of STOVL aircraft acquired during nearly four decades of operations of Harrier on land and sea".  He went on to cite the STOVL variant's short runway and land-basing flexibility as a major discriminator in the down-selection decision.

Another factor that tipped the decision in favour of the F-35 STOVL variant was the aircraft's ability to meet an ISD of 2012.  "Timing was a key driver," said Chief of Naval Staff and First Sea Lord, Admiral Sir Alan West. "All the indications were that if we went for the [CV] option we would have incurred a delay of about two years on our programme." [This statement has become rather ironic given BAE Systems' opinion that an ISD of 2014 or even 2015 is far more realistic for CVF-01 than the official 2012]

MoD and industry officials also acknowledged that selection of the F-35 STOVL variant over the CV version would bring greater benefits to UK industry participation in the JSF programme.  Rolls-Royce (which has primary responsibility for the STOVL lift system) and BAE Systems will in particular gain from the decision.

Ultimately, observers saw the decision as hinging on the wider balance of investment judgments.  Returning to catapult-launch and arrested-recovery operations with the JSF CV variant would have cost more, but pound for pound represented the most cost-effective way of getting bombs on target.  The chosen STOVL option will deliver a more modest capability, somewhat below that of a CV solution, but will cost less overall.  That in turn leaves more money available to be spent elsewhere in the MoD's hard-pressed equipment programme.  And by selecting an "adaptive" design for CVF, the door has not been completely closed on the possibility of CTOL operations in the future. 

There were rumours in the summer of 2003 that the UK was again examining the requirements associated with operating the F-35C from CVF, and interestingly, in early 2004 Aviation Week magazine repeatedly reported that the UK was re-considering its commitment to the STOVL F-35B as result of performance issues (largely due to weight problems) and likely delays in the schedule of STOVL variant compared with the CV F-35C.  The magazine said the UK was considering a buy of 80-85 F-35C's instead.  Other reports confirmed that the UK was reconsidering its choice of the F-35B rather than the F-35C, with a final decision then expected in late 2004 or the first half of 2005.  Clearly a switch to the F-35C meant that the CVF's would be built as conventional take-off and landing carriers, with catapults and arresting gear.  However by June 2004 Lockheed Martin appeared to be have considerable  success in resolving the problems related to the JSF programme and in particular the F-35B, and a switch by the UK seemed increasingly unlikely, although the reports give an indication of the intense pressure to perform as promised that was on the Lockheed-Marin JSF team in late 2003 and early 2004.  

Even more confusingly, after the defence cuts announced in July 2004 which reduced the operational requirement for RAF offensive strike aircraft to just 64 deployable front-line aircraft, there were suggestions that some elements in the RAF were now advocating a switch from the STOVL F-35B to the CTOL F-35C variant in order to avoid having an excessive proportion of less capable (at least in terms of range and payload) STOVL aircraft in the shrunken force.  There were also some reports that clearing the F-35B for ski-jump operations would be bigger technical challenge than expected, and the UK will have to pay most of the bill. 

In Spring 2005 the MOD admitted that it was reviewing which variant of JSF would best meet its Joint Combat Aircraft requirement  and that a decision would inform the CVF main investment decision then due in early 2006.  The analysis would take into account more mature JSF cost and technical data and revised force mix assumptions.   The cancellation of the Future Offensive Air System (FOAS) in June 2005 opened up the possibility of a split version JSF buy - perhaps 60-75 navalised and carrier capable aircraft probably (but not certainly) STOVL, plus a similar number of a longer range and purely land based variant that is unlikely to be STVOL.    

During this period American decisions (particularly the failure to agree a ITAR technology transfer waiver for JSF to the UK, and the proposed cancellation of the alternative F-136 engine being developed by GE and Rolls-Royce) began to have a large impact on UK thinking.

In special hearings before the US Senate Armed Services Committee on 14 March 2006, British, Australian and Italian officials expressed their unhappiness about the lack of consultation in U.S. handling of the JSF program and technology transfer delays.  Minister for Defence Procurement Lord Drayson issued a stark warning that unless Britain's technology access needs are met, it will quit the JSF program. The British government's stance appeared uncompromising. Either provide the U.K. with "operational sovereignty" on its Joint Strike Fighter (JSF) aircraft, or watch London pull out.

"We have no reason to believe that our discussions with the administration will not be successful, but without the technology transfer to give us the confidence to deliver an aircraft fit to fight on our terms, we will not be able to buy these aircraft," Drayson cautioned. "I am spelling this out because it is so important to make our intentions clear. I know the British can be accused of understatement."   Minister's began to talk about a "Plan B" alternative to the JSF if the UK pulled out of the JSF project at the end of 2006, something that would have been unthinkable in 2003 or 2004. - almost certainly a navalised Eurofighter Typhoon, although defence analysts struggled to take this seriously.

In the event the UK signed a Memorandum of Understanding (MoU) on the next phase of the Joint Strike Fighter (JSF) programme - production, sustainment and follow-on development (PSFD) - on 12 December 2006. The MoU sets out the framework for purchasing JSF and supporting and upgrading it through life. It also provides for the pooling of the partner nations' collective buying power in a common support solution, and of their resources and technology in follow-on development. It does not, however, formally commit the UK to buying any aircraft.   The first two UK JSF's are due be ordered in late 2008 or early 2009 for delivery in 2011