Artist’s impression of F-35B on the deck of HMS Queen Elizabeth.

Does Air Forces’ Procurement of STOVL Fighters Make Operational Sense?

07:32 GMT, September 10, 2009 Both the Royal Air Force (RAF) and the Italian Air Force (Aeronautica Militare Italiana, AMI) are betting their future attack capabilities on the procurement of an advanced STOVL aircraft - more specifically, the F-35B version of the LIGHTNING II Joint Fighter Aircraft. Based on current plans, the RAF stands to acquire 150 F-35Bs under the JCA (Joint Combat Aircraft) programme with the Royal Navy’s Fleet Air Arm, that will be operated in a similar fashion as the current Joint Force HARRIER. The AMI on its part is aiming at a mixed force of 69 F-35As CTOL aircraft and 40 F-35Bs, while the Italian Navy will also order 22 F-35Bs to replace its AV-8Bs in what for the time being remains an independent naval aviation (GrupAer).

It is this article’s contention that such a heavy emphasis on STOVL technologies and operational concepts do raise a number of perplexing questions, and it is hardly justifiable in operational terms. Rather, there are reasons to suspect that the real rationale for this keen interest towards the F-35B is eminently political, and it has to do with the air forces’ desire to maintain their traditional role as the main, and ideally only, purveyors of air power in our age of expeditionary conflicts.

It is certainly only logical and indeed commendable for a Service to have an exceedingly high notion of its own responsibilities and capabilities, and by the same token even fratricide battles over budget allocations, self-destructive as they are shall arguably be understood as an unavoidable consequence of years over years of savage cuts in defence expenditure. But, a line has to be drawn somewhere. The truly alarming aspect of the RAF’s and AMI’s current STOVL plans, and thus the reason for this article, it is not that such plans effectively imply stealing the naval aviation’s power projection lunch and indeed suppressing it to take its place - unpalatable as this prospect might be for those wearing Navy uniforms. What really matters is, given the multiple limitations inherent with the STOVL concept, the promised “STOVLisation” of air attack assets effectively translates into asking the taxpayer to pay a significant higher price in exchange for zero extra operational capabilities - indeed, for significantly l o w e r operational capabilities, as this article intends to demonstrate. The real goal, to the obtained at such a high cost, consists in guaranteeing the role of the air forces as the rapid intervention and power projection tool of choice.


STOVL Rationale - Then and Now

Back in the early ‘60s, NATO formulated a Basic Military Requirement (NBMR-3) for a supersonic strike fighter capable of V/STOL (as it was formulated back then) performance. The rationale for this requirement was clear and evident enough. NATO Air Forces needed a residual strike/ground attack capability that would be able to survive the only too likely devastating counter-aviation attacks on all NATO airfields in Germany, launched by the Soviet and Warsaw Pact’s Front Aviation forces (plus quite possibly ballistic missiles) in the opening phases of a major conflict. NATO thus wanted an aircraft that could be dispersed to, and operate from whatever secondary and/or improvised airstrips could be available - even including selected highway sections and other emergency surfaces, as well as the still useable sections of cratered main runways.

It was abundantly clear that given a number of annoying physical principles and technological issues, any such supersonic V/STOL strike aircraft would by definition be markedly inferior to a contemporary CTOL design in all performance parameters but V/STOL capabilities. V/STOL was thus basically a desperate solution in view of a desperate problem - not unlike the contemporary Luftwaffe’s plans to send all of its flight instructors with their ALPHA JETs (!) in a mass attack against the Soviet armoured columns in the very opening phases of a major conflict (because, as the late Gen. Steinhoff dryly told me, in such a conflict there would be neither scope nor time to form new pilots, and thus training assets were eminently expendable).

It would be far too long to trace down here the tortuous road that led to the collapse of NBMR-3, and eventually resulted in the RAF being the only Air Force to field a STOVL fighter under the guise of the less capable subsonic HARRIER. A point that needs some attention, however, is that back then no other NATO air force saw any reason to devote part of its resources to the procurement of STOVL combat aircraft - despite the Cold War stakes being extremely high. Simply put, the many limitations and higher costs of STOVL technologies were perceived as being out of proportion to the limited operational benefits.

Needless to say, in the current operational scenarios, none of the above applies any longer. The possibility of counter-aviation attacks on our main operating bases, either at home or even in an expeditionary context is virtually down to zero. Even the residual risk of a ballistic missile launch against expeditionary air bases would arguably require not the pre-emptive dispersal of combat aviation assets across a number of smaller bases, but rather the opposite approach of concentrating them on a few main bases heavily protected by adequate BMD systems.

The only country that could conceivably still maintain a requirement similar to NBMR-3, albeit in a different strategic context is Israel. Indeed, the Israel Air Force is understood to be pondering on the possible procurement of a mixed F-35A/F-35B fleet, not unlike the AMI although for completely different reasons. No final decision has been reached, however, and furthermore I am not aware of any official IDF document detailing the rationale for such a mixed fleet. So, we will put this aside for the moment.

The STOVL rationale now being put forward by air force circles in both Britain and Italy is of a completely different nature, and hinges on the concept’s supposed advantages and benefits in an expeditionary scenario. While these advantages remain based on STOVL aircraft not being tied to traditional runways and airfield, this capability is now perceived in terms of operational flexibility rather than survivability. STOVL aircraft are described as being the ideal solution for expeditionary operations, thanks to their supposed ability to be brought quickly in theatre as well as being inherently suitable for operating from forward/austere bases that would not accept CTOL types. Forward basing of tactical aircraft by definition reduces the distance to the battlefield, which translates into improved response times to urgent calls for air support, increased aircraft surge rates, and higher combat load or/and longer times on station for the same fuel fraction.

Does this make sense? It certainly does. Indeed, the concept has already been demonstrated in real combat operations, including most notably the RN’s SEA HARRIER being moved on an improvised strip ashore during the Falklands conflict, the forward basing of USMC HARRIERs during “Desert Storm”, and more recently in Afghanistan. During “Desert Storm”, the twelve USMC aircraft based at an ARAMCO helicopter field at Tanajib in Saudi Arabia, south of the Kuwaiti border were within 65km and five minutes flying time from the battle, whereas CTOL combat aircraft flying from bases in southern Saudi Arabia and the coastal Gulf states as well as from aircraft carriers had to cover at least 250km to reach the nearest targets in Kuwait. By the same token, during the earlier phases of Operation “Enduring Freedom” the six GR7A HARRIERs of No 3 (Fighter) Squadron, based at Kandahar airfield while the single runway there was being slowly rebuilt were the only combat aircraft able to operate from the south of the country, and the sole local fighter asset readily available to support allied troops. And even at a later date, the STOVL performance of British GR7/GR9s and USMC AV-8Bs based at Kandahar were of pivotal importance in enabling simultaneous combat, logistic support and civil operations all using a single runway. Further, the very nature of combat operations in Afghanistan has highlighted the fundamental importance of nearly immediate, “on call” air support.

But this is only part of the story, for there also are other considerations.


A Reasoned Critique

While the operational advantages of land-based STOVL assets under certain operational conditions are self-evident, so are the inherent disadvantages and limitations, as well as the much higher procurement and life-cycle costs. The question thus is of whether these operational conditions actually are of such an overwhelming importance, or/and are being encountered so often, as to justify organising nearly half (AMI) or the totality of attack assets (RAF) on STOVL aircraft.


From Where to Where?

When talking of land-based aircraft being deployed for an expeditionary operation, a not-so-trivial consideration involves the question of where the aircraft are taking off from, and where they are to land in theatre.

It would seem rather obvious that we must reason in terms of aircraft leaving a home base and performing a ferry flight, involving a certain number of in-flight refuelling operations or/and en-route stopovers at available own or friendly bases, before landing at a main airport in theatre or anyway close to it and then being finally moved to their intended operating base(s) (if the airport of arrival can not be used for this purpose). For if we rather start thinking in terms of the aircraft arriving in theatre on the deck of a carrier, then we are inescapably led back to the logic of naval, rather then air force, operations.

The respective ferry range performance to be eventually demonstrated by the F-35A and F-35B, respectively is still a matter for guesswork rather than any solid evidence. It remains, though, that the F-35B will carry much less internal fuel (some -2,000kg) than the CTOL variant and will thus have an inferior range (some -600km), period. This indicates that far from simplifying expeditionary deployments, the F-35Bs in RAF’s and AMI’s service will significantly complicate them due to the need to plan more refuelling rendezvous or stopovers.


How Austere is Austere?

Much hype is being placed on the F-35B’s expected ability to operate from deteriorated runways that could not be used by conventional jets, and dubious mentions of “improvised runways” as well as clearings, tennis courts, parking lots and the like even appear in print. Let’s set the record straight.

Pure VTOL for combat operations is a fake that does not even need further discussion. If a theoretically VTO-capable aircraft is to take-off with full internal fuel and any meaningful payload, then a lot more than just a pad is needed. As regards operating (in the STOVL mode) from improvised strips, the F-35B will not offer any inherent advantage over the F-35A. Whatever capabilities the JSF will have in this regard, are embodied in its basic design (particularly as regards the strength and geometry of the landing gear) and are thus equally shared by both versions. Indeed, if anything the F-35B could be expected to be l e s s suitable than the F-35A for using unpaved runways or grass strips, due to its power plant arrangement creating a much more serious risk for FOD ingestion.

As a collateral note, the current negative experience with the F-22, whereby more than half of the aircraft’s appalling maintenance record - 30+ maintenance hours for 1 flight hour! - is reportedly being caused by the delicate RAM stealth coating, casts very serious doubt on the notion of any version of the JSF being confidently deployed in a “dirty” environment. One might wonder for how long a JSF would maintain its stealth features, when operating e.g. from Kandahar’s notorious “dust bowl”.

What the F-35B will certainly offer is the capability to take-off from shorter runways than would be required for the F-35A. Here again, precise data on the aircraft’s TO run lengths at different weight configurations and under different environmental conditions are still years away, but it is understood that the original USMC requirement was for a TO run of 450ft (137m) or less under ISO standard. This is a far cry from the 2,500-3,000m runways that are typically present at main bases for CTOL combat aircraft, and would certainly seem to open up completely new operational possibilities as regards forward basing. It would however be advisable to ponder on two not totally insignificant points:

• Even though a STOVL aircraft is by definition capable of short take-offs, this capability is actually exploited (as regards land-based deployments) far less frequently than one might think. Whenever possible, it is more convenient and practical (particularly in terms of max. TO weight in hot/high condition) to operate even STOVL aircraft in a quasi-CTO mode. For instance, the already mentioned forward site for USMC HARRIERs at Tanajib during “Desert Storm” actually had a 2,500m runway (1,800m of asphalt plus 350m of concrete at both ends).

• STOVL capabilities come at a hefty price in terms of higher overall weight and inferior payload both as regards fuel and weapons. A STOVL aircraft would thus by its very nature deliver a smaller combat load at a shorter range than a comparable CTOL design. While it could certainly be maintained that this is an acceptable price to pay in order to enable STOVL operations when and where CTOL ones are not possible, it must be appreciated that the STVOL shortcomings are built-in and thus p e r m a n e n t. They will always adversely affect the aircraft, and cannot be traded back for a higher payload when there are no real operational requirements for STOVL performance.


How Forward is Forward?

As already commented, in an expeditionary scenario the notion of aircraft dispersal to reduce vulnerability to counter-aviation attacks does not make much practical sense. Rather, the main advantage of the STOVL concept is supposed to lie in bringing the aircraft closer to the battlefield through forward basing. This indeed sounds like a sensible proposition - to a point.

We must logically assume the availability of at last a Main Operating Base (MOB), from which CTOL combat aircraft will also be operating. Given that these aircraft will be at the very least capable of carrying the same payload at longer ranges than STOVL types (when not a larger payload at longer ranges), forward basing would only start to make a real difference, when the targets to be engaged are hopelessly out of CTOL aircraft’s unrefueled range, or/and need to be attacked within the slightest delay as possible. One might question whether such operating conditions would be encountered that frequently as to justify the whole exercise.


Logistic Implications

Operating modern combat aircraft from forward sites is a b i g logistical challenge. Even assuming that no maintenance activities of any sort will be performed there (which is not without its own risks), the aircraft’s insatiable appetite for fuel, ordnance and other stores will need to be somehow satisfied. Incidentally, one might note that the F-35B will likely have close to trice the fuel consumption of a HARRIER, and will by definition be considerably thirstier than the F-35A.

Intuitively enough, the simplest way to support a forward base would be by transport aircraft in the C-130 class. This, however, dictates very precise limits on how short the short runway there, and how primitive the airport infrastructure can actually be. For this very reason, the NBMR-3 requirement was paralleled by the NBMR-4 requirement for a V/STOL transport aircraft. Failing this, one has to rely on helicopters or/and trucks. Relying almost exclusively on vertical lift to supply forward bases would however place an enormous burden on already limited helicopter capabilities.

Further, in the prevailing asymmetric combat conditions of expeditionary operations, forward bases would require considerable resources to guarantee continuous, round-the-clock perimeter protection against mortar/rocket attacks, suicide bombings and the like. Much the same applies to the need to protect the resupply convoys, is the land approach is selected.


The USMC Model

It is highly instructive at this point to take a look at the rationale for the F-35B as formulated by the US Marine Corps, i.e. the world’s leading expeditionary force.

The USMC requirement for the JSF programme mandated a multi-mission aircraft capable of operations from austere shore facilities as well as amphibious ships and other sea bases. Such basing flexibility is fundamental to the expeditionary nature of the Marine Corps, and indeed is the only reason why the Marines want a STOVL aircraft. Basing flexibility not only provides the foundation for forward basing which improves responsiveness, but also increases the number of airfields from which to conduct operations, thus allowing for more assets to be brought into theatre.

This sounds very close to the STOVL rationale as being expressed by the RAF and AMI. But the USMC’s doctrine, “Operational Manoeuvre From The Sea” (OMFTS) seeks to avoid establishing a traditional logistics base ashore from which to conduct follow-on operations. Rather, manoeuvre forces will move directly from the ships to their objectives with a minimal footprint. Accordingly, OMFTS calls for the majority of firepower, to include aviation, to remain afloat and only go ashore if necessary. This means that the Corps’ F-35Bs, like the current AV-8Bs will operate primarily from naval ships - where they can be more easily provided with fuel, ordnance, and maintenance without becoming a logistical burden - versus land bases. While forward-basing the aircraft ashore as early as feasible would arguably look like the best way to improve operational effectiveness, the USMC opine that sustainability considerations rather dictate for them to remain onboard.

This approach is aptly underlined by the evolution of the US Navy amphibious assault ships, from the LHA to the LHD, LHD-8 and now LHA-6 designs with progressively expanded aviation capabilities. More specifically, the new AMERICA class, with no deck well but able to operate up to 24 F-35Bs are dedicated STOVL carriers but in name, even though due to deference toward the “real” carriers they will not be fitted with a sky-jump.


Ulterior Motives

The Royal Air Force and the Italian Air Force believe that the operational advantages offered by the STOVL concept in expeditionary scenarios outweigh its many limitations and shortcomings as well as its significantly higher cost. The Services are thus prepared to invest an important part of their limited resources toward the procurement of a lower number of less capable (but for the STOVL performance) aircraft.

This approach is not shared by any other air force in the world. The US Air Force, despite an increasing emphasis on expeditionary roles, did briefly consider a possible mixed F-35A/F-35B buy, but eventually dropped the idea. Even other European air forces such as the Belgian Air Component or the Royal Netherlands Air Force, which are reorganising and re-equipping themselves around the main mission of participation to Coalition expeditionary operations, show no interest for STOVL solutions. It is a very curious coincidence, if indeed it is a coincidence, that the only two air forces to discover a pressing need for the F-35B are those in countries with a naval aviation, and aircraft carrier programmes.

With the end of the Cold War and the emergence of new strategic scenarios that place a particular emphasis on rapid intervention and power projection missions all around the world, the RAF as the world’s oldest independent air service was very quick to recognise that these scenarios contained the seeds of the possible growth of a very serious threat to its overall status within the UK military. This was further reinforced by the legacy of the Falkland War, and the envious comparison between the RAF’s and Fleet Air Arm’s respective roles in that expeditionary conflict.

With attention being increasingly focused on global contingences, air forces that are incapable of worldwide power projection missions - that is, everybody except the USAF - risk being reduced to a second rank role in ensuring defence of the national airspace against increasingly unlikely threats, while army, navy (including naval aviation when available) and amphibious assets become the nation’s strategic spearhead. This being clearly not acceptable, the only way out consists of either piggy-backing on US-led coalitions, whereby air bases abroad and air refuelling assets to get there will conveniently become available courtesy of Big Brother - or, ensuring a passage for the air force’s aircraft onboard the navy’s carriers, supplementing and then effectively “elbowing out” naval aviation planes.

STOVL assets are absolutely pivotal to this, as they are the only type that can be moved back and forth land bases and carriers with no significant modifications to the aircraft and but a minimum of specific training for their pilots. (Much the same of course applies to dedicated shipboard CTOL types such as the F-35C being flown by carrier-qualified pilots, but this remains strictly within the framework of naval aviation). Hence, in a British context the creation of Joint Force Harrier (JFH) in April 2000, its subsequent quick metamorphosis into a purely RAF-oriented force with the premature and unnecessary withdrawal of the FA.2 air defence aircraft (air forces are not interested in maintaining shipboard air defence capabilities), the choice of the F-35B as the new JCA (Joint Combat Aircraft) for both the RAF and the RN, and plans for the JHF scheme to be maintained for a future Joint Force Lightning. The whole then came to its logical conclusion in early June 2009, when the outgoing head of the RAF, Air Chief Marshal Sir Glenn Torpy, openly questioned the future relevance of the fixed-wing Fleet Air Arm and effectively called for it to be folded into the RAF. The Italian Air Force for its part clearly intends to move along very much the same path, starting with the discovery that it needs an F-35B fleet twice the size of the Navy’s and circulating comments about the “logistic advantages” and “savings” that a joint structure would enable.

Now the notion of a joint STOVL force - or even an Air Force-managed and - commanded force if you prefer - for both land-based and shipboard operations does indeed make a lot of sense. This is not simply in terms of simplified logistic support and other such measures to please the bean counters, but much more importantly in view of a far greater operational flexibility. The fact that the aircraft can be continuously redistributed between carrier decks and land bases according to the demands of the respective theatres, and indeed it is even possible to concentrate all available resources, either at sea or on land if the operational conditions allow, is a first-class force multiplier in an expeditionary environment. The validity of this concept was clearly demonstrated by the recent deployment of JFH aircraft to Afghanistan.

Further, this deployment flexibility also enables significant savings as regards the required numbers of aircraft. The current British plan for a total of 150 JCA is clearly predicated on the aircraft’s “swing” capability for land or sea basing, and should the programme be split into two separate requirements then a substantially larger total fleet would be needed.

Point is, the whole approach hinges on the availability of STOVL carriers - or to put this in a different form, the possibility of using STOVL carriers as “mobile airbases” is the only really valid rationale for an air force’s attack fleet to be largely or exclusively based on STOVL aircraft. This is not only in terms of the joint force operating from the carriers in a pure naval aviation style, but more broadly in using the carriers to maintain the extremely important strategic option or rapid deployments virtually worldwide, and irrespective of the availability of en-route bases or/and adequate in-flight refuelling assets.

This point is what makes the ongoing defence spending debate in the UK, whereby the CVF programme is expected to be at the very centre of the process of formulating the new “Strategic Defence Review”, particularly sensitive. It would appear that the increasingly desperate fratricide battle for a bigger chunk of the meagre defence budget is causing at least some sectors within the RAF to rediscover their traditional anti-carrier bias, and to side with the Army in disparaging the CVFs as “Cold War relicts” that could and indeed should be cancelled in order to release funds for more pressing needs. One may guess that these sectors reckon that Britain will anyway no longer be in a position to sustain an independent power projection capability, and would thus be content with just a supporting role, Belgian/Dutch style, in any US-led Coalition - with the important provision that the Royal Navy, too, shall be denied such a capability.

Should the RAF/British Army “unholy alliance” really achieve the unthinkable, and manage to steer the “Strategic Defence Review” towards cancellation of the CVF programme, it would be rather interesting to see whether the RAF would maintain its current choice for an all-STOVL attack fleet, or would rather all of a sudden discover that the F-35A is a much more sensible proposition. But if the RAF really intends to take this path, they are sawing the branch on which they are seated.

The prospective situation in Italy seems to provide less reason for concern. The AMI will anyway operate a majority of F-35As, and provided a strategic deployment via ferry flight is feasible, there will thus be no need to deploy STOVL aircraft in an operational environment that doesn’t require them just to prove a point. Also, the CAVOUR STOVL carrier is already in service, and the presence of a total of 22 (Navy) + 40 (Air Force) F-35Bs will not only ensure that her deck will always be more than well stocked, but it might also assist in the Marina Militare’s ongoing effort to obtain when not a second carrier then at least a STOVL-capable multi-purpose vessel. If the price to be paid for such a ship is the creation of a Joint Force Lightning, or even the fixed-wing Grupaer being completely reabsorbed into the Air Force, my tentative guess is that the Navy would accept it.

Be this as it may, what would arguably be the most logical solution, as well as the one providing better returns on taxpayer’s money - F-35A for the RAF and the AMI, F-35B for the Italian Navy, and F-35B or much better F-35C for the Fleet Air Arm - remains completely out of the question. Oh, well…


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by Dr. Ezio Bonsignore, Editor-in-Chief of MILITARY TECHNOLOGY (MILTECH)