An F-35 update

A brief summary of where we are 

The F-35B test fleet has received the F-135 engine fix that makes sure there won't be a repeat of the hard rubbing of fan blades and stator that lead to the fire on the USAF AF-27 aircraft last year. The only aircraft in the test fleet which has yet to receive the pre-trenched stator is BF-5, and that's because it spent the last 6 months inside the McKinley climatic laboratory in Eglin, to undergo extreme climatic testing. 
The whole fleet of F-35s is due to be fitted with the pre-trenched stator element by early next year. The stator element received a "trench", cut in during production, which ensures there is not excessive rubbing with the fan blades. The alternative, used to quickly fix some of the test aircraft, is to fly a series of manoeuvers planned out to gracefully cut the trench in. 
The fix is said to be effective. The loss due to the greater gap in the stator is said to be just around two degrees, which is not significant. However, engineers are considering whether a more effective change is possible, affordable and needed.

As mentioned, BF-5 has recently completed climatic testing. The results seem to have been good, and there have not been particular issues arising either from extreme heat or extreme cold, or everything in between. 

 

Sun bathing to replicate the intense heat of a day parked on a runway in hot climate zones

Icing cloud test

Flying in the freezing air

Flying without moving from the spot, including in VTOL modes. Testing the F-35B required a complex infrastructure.

In May, 6 F-35B of the USMC are due to deploy at sea on the USS Wasp for the first Operational Testing phase (OT-1). This test deployment will be a work-up to the incoming IOC, still scheduled for July. USMC F-35Bs are moving through the depots to receive the modifications they need to get up to the latest standard. As of March, 5 jets were undergoing the refit at the Cherry Point Fleet Readiness Center - East. 2 more should have already been redelivered, and other work is being done by the USAF's own Depot, in Utah. 
A total of 10 frontline aircraft will be modified in order to achieve IOC. 

F-35B Ski Jump trials have begun in Patuxent River, and are expected to finish by mid-May. The first images of an F-35B taking off from ski jump are expected soon, and this will be a significant milestone for the british and italian needs. 

AF-1 has begun flying test sorties with a very asymmetric external load (one wing with clean pylons, the other with two GBUs and one Sidewinder) as part of the work needed to clear external carriage of weapons in the Block 3F software. 
Test sorties have been flown with 4 Paveway IV and 2 ASRAAM on the wing pylons, as well, to begin the integration of the british weapons load configuration expected at Block 3F (up to 6 Paveway IV, 2 internal and 4 external, and 2 external ASRAAM). 

AF-2 and at least another F-35A have been flown in a first series of trial sorties, testing basic fighter maneouvering with the assistance of F-16s. These have been defined "dogfights" in some press reports, but it seems we are still talking mostly about testing the handling and finding where the flight control laws can be adjusted. Building on high Angle of Attack testing and departure trials, the test pilots have begun flying with and against F-16s to see what the F-35 can do. The report says that there is margin to relax the flight controls to achieve greater agility, perhaps leading to a reversal of the degradation reported a few years ago. 

AF-2 is also preparing to begin, this June, the firing trials with the 25mm gun. The gun becomes available with the Block 3F software. 

Earlier, Col. De Smit of the dutch air force and Lt Col Lee Kloos, USAF, both coming from the F-16, went on record saying that an F-35 compares nicely in terms of turning to "an F-16 with combat load". They both said that a clean F-16 will turn better, but noted that a clean F-16 has little to offer in terms of range and weaponry, and is never actually flown operationally in such a way. 
Transonic acceleration, as well as climbing and descent, are described by the two pilots as matching those of a clean F-16 Block 50.  
Later on, with the beginning of Air Combat Manoeuvre training, we will no doubt hear more. 

 
The F-35C is due to have its DT-2 period of trials at sea between august and september. This time, the carrier involved is expected to be the USS D. Eisenhower. 



Remaining issues

Issues remain in the development of ALIS, the logistic planning software. Progress is slower than desired, and this impacts on the time needed to carry out maintenance. It is also one of the problems remaining on the road to USMC IOC, as the portable, deployable ALIS terminal isn't yet ready. 

Software development also remains, unsurprisingly, challenging. At IOC, the USMC seems set to not have access to the intended "4-ship fusion", which connects 4 F-35Bs in a package able to share the complete situational awareness picture, so that any target spotted by one aircraft is made visible to the others as well. 
Fusing the sensors inputs coming from 4 different aircraft is currently causing issues, as the differences in how each aircraft see the target generate multiple symbols on the screen, effectively making it hard for the pilot to know which target mark is the correct one. 
Fusion will initially be limited to pairs, while software clear up progresses with the aim of fixing this issue by October. 

The F-35B is still dealing with the Dunlop tyres, which, despite improvements made since 2013, still wear out quicker than planned. A new tyre design will follow. 

Software aside, the greatest issue still standing is the F-35B's 496 Bulkhead, which in 2004 was switched to aluminium from its original titanium design in order to reduce weight, with the unwanted result that, during airframe durability testing on the ground, it cracked, and then severed, at just after one simulated flying life. 
In order to be certified for its intended 8000 hours life, the F-35's fuselage must survive 2 simulated life cycles, with a third life cycle planned for validating the possibility of extensions beyond the 8000 hours. 
Durability testing on the F-35B's airframe has been stopped many months ago because of the 496's failure, and a redesigned bulkhead is needed. 
The problem will not affect the F-35B in the immediate (it'll be years before any of the aircraft produced so far enters the dangerous number of flying hours), but it is to be hoped that airframe stress tests will resume soon. In April 2014 Rear Adm. Randy Mahr, deputy program manager, said that the solution to the 496 problem was known and a redesigned bulkhead will be embodied into production from the LRIP 9 onwards, with the same component retrofitted during depot maintenance on the F-35Bs of the earlier lots. It is not clear at the moment if this is still the case, or if the development of a full, effective solution has slipped. It remains one issue to work upon. 

One non-issue which instead made a lot of noise on the press is the fix to the F-35B's weapon bay in order to fit the Small Diameter Bomb II. The apocalyptic tones used in some reports are definitely excessive when the fix is actually about a small change to the passage of an hydraulic line and some wire bundles. Moreover, the F-35 cannot exactly be blamed here, since the B's weapon bay was downsized all the way back in 2004, while the SDB II, which is not yet in service, began development in 2010. The "fault" is of the weapon, but the fact is that is simpler to carry out the small modification to the weapon bay rather than try to further miniaturize the bomb. Much drama has been made about how the SDB II won't be available on the F-35 before 2022, without considering that the SDB II won't be operational before 2017 at the earliest (on USAF F-15E), which becomes 2019 on US Navy Super Hornets. 
Moreover, it is not like F-35 will instantaneously make up the whole of the US air power: for many more years there will be F-15Es and F-16s to carry out a big share of the game. No real need to panic. 

The F-35B modification will be part of Block IV work, and the Joint Project Office is designing the fix keeping track of the requirements for partner weapon requirements as well. For the UK, this includes Meteor and SPEAR 3. 



British Status of Play

On a british-specific perspective, the 17 (R) Squadron stood up in Edwards AFB as the F-35 OEU squadron. For now it is equipped with BK-1 and BK-2 only. These aircraft came out from depot maintenance and received the latest modifications. 
BK-3, which is not instrumented, is in Beaufort as training aircraft, embedded in the USMC training squadron 501. 
BK-4, the next aircraft to be delivered, is instrumented and will joint 17(R) Sqn as third and last test platform. 

Procurement of a first batch of 14 aircraft has been authorized. The expected LRIP split is 4 in LRIP 8, 6 in LRIP 9 and 4 in LRIP 10. This should lead, by end-2018 or 2019 to the following situation: 

- 5 F-35B training fleet in Beaufort
- 3 F-35B test fleet in Edwards
- 9 F-35B in 617 Sqn, to RAF Marham 

Where to find F-35s in 2018

Speaking of RAF Marham, more than 300 million pounds have been assigned for infrastructure preparation in the base. Back in June 2014 it was announced that 3 Landing Pads will be built in order to practice vertical landing. A runway renovation is planned. The current Hardened Aircraft Shelters used by IX squadron with Tornado GR4 are due to be modernized ahead of welcoming 617 Sqn when it arrives from America (although the extension of the service life of the third Tornado squadron on base complicates somewhat the management of spaces as the major building work begins). 
Marham is also expected to receive an Integrated Training Centre which will train british pilots from 2019 and that will welcome other european crew training needs too, probably beginning with Norway's. 
Again, Marham is expected to eventually include a MRO plant for maintenance and upgrade, and this will require a large hangar and serious infrastructure. Another hangar complex is needed to host the stealth coating maintenance and the RCS testing laboratory which certifies the Low Observability after each coating re-application. 

Meanwhile, a Virtual Analysis Laboratory has opened in Ampthill, UK, to allow british-based software experimentation, analysis and development through simulation. The work done here will inform and direct software development carried out at the ACURL (Australia, Canada, United Kingdom Reprogramming Laboratory) at Eglin, in the US.


In Culdrose, funding is expected soon to rebuild the current Flight Deck training facility (the "dummy carrier" HMS Siskin) so that it ceases representing an Invincible class deck and enters the Queen Elizabeth age instead. The 14 Sea Harriers currently used for deck handling training are also expected to be replaced as they do not "impersonate" the larger and heavier F-35B well enough. A small number of F-35B mock-ups will be procured instead, for the handling and parking proper, while an option for deck runs and engine-on rolling training is getting back some ex-RAF Jaguars, which are thought to provide a more F-35B like feel. 

A Navy News graphic shows the existing HMS Siskin, surrounded by the shade of what Queen Elizabeth's deck would look like. In reality, it seems that there will not be a whole deck mock-up, but just the stern area, up to and including the first elevator.

A busy HMS Siskin training deck handlers. This is where you can still see Sea Harriers engines in action, although none of the aircraft can fly.

 
The 5-strong F-35B training fleet is expected to move out of the US to begin operating in Marham in July 2019. That's when US-based training of british F-35B crews is expected to end. 
Actually, the last of a planned 24 british pilots to be trained at Beaufort is expected to complete the course by May 2018. 

There is not yet a date for the standing up of the second frontline squadron, 809 NAS. For now, the stated purchase target stands at 48, including the test fleet. Greater clarity is hoped to come from the new SDSR. 



Where do we go from here? 

The beginning of the F-35B in british service will be relatively modest, at least compared to what the aircraft will be able to do later on. With Block 3F, the F-35B at IOC in 2018/19 will be able to carry 2 ASRAAM externally and up to 4 AMRAAM internally in a fighter role; or 2 AMRAAM and 2 Paveway IV in internal-only configuration, or up to 4 AMRAAM, 2 ASRAAM, 4 Paveway IV, or again 2 AMRAAM, 2 ASRAAM and 6 Paveway IV using both internal and external carriage. 
 
The gun pod will be available as well, provided that a new "no gun" budgetary stunt is pulled, like that, then aborted, which was played with the Typhoon.  

Block 3F capabilities

Block 3F comes with some limitations to the use of the EOTS as IRST sensor; and with no video-downlink capability, which is unfortunate as in recent years this has become a key factor in providing air support to the troops on the ground, sharing imagery with the JTAC. 
In defence of the F-35, it must be said that when the requirements were written and development started, the ROVER video-downlink did not exist yet. Clearly, the capability to share sensors imagery with the troops on the ground will be high on the list of priorities for development of Block IV, the software load for the 2020s. An IR pointer is also likely to be added. 

At entry in service, the F-35 will be able to share targeting information through self-determined GPS position data. Not quite the same thing as having full imagery, but it should be enough of a beginning. 

A notional road map for future developments

The capabilities will expand a lot going forwards with the Block IV software. Last 17 march, the deputy manager of the F-35 programme, Rear Adm. Randy Mahr, provided a document explaining some of the planned next steps. The presentation includes a table of enormous interest about british weaponry plans.

Block IV apparently is now going to comprise 4 different software releases, and I can’t quite say at the moment how this relates to the earlier assumption of having two stages, Block 4A in 2021/22 and 4B in 2022/23. 

March 2015 document showing the list of candidates for Block IV integration.

The four releases will incrementally add new weapons to the F-35, and for the UK the first candidate is SPEAR 1 – Penetrator, which is the new bunker-buster warhead developed for the Paveway IV bomb. This new warhead, which keeps the external shape of the current one but comes with an hardened penetrating body inside, is the de-facto replacement for the current 2000 lbs Paveway III used on Tornado GR4. The III is destined to go out of service alongside Tornado, it seems. Raytheon Uk and the MOD have been working on the new warhead option for the Paveway IV for a while now, and a production contract is expected soon.

The second candidate is “SPEAR seeker”. The definition is somewhat puzzling and not detailed, but I believe it probably refers to the proposed addition of an IR Imaging seeker again on the Paveway IV, in order to dramatically improve its ability to hit moving targets.

Spiral development of Paveway IV is all included in Selective Precision Effects At Range Capability 1 (2 being the Brimstone developments, and 3 the whole new weapon by the name of Spear).

There is also a “ASRAAM new build” candidate, which suggests that the Royal Air Force thinks it is time for a Capability Sustainment Programme for the ASRAAM. This has been loosely planned for years, and is supposed to build on what is being done for the CAMM / Sea Ceptor missile, itself an ASRAAM derivative.

Most important is the planned addition of Meteor. Integrating this weapon is particularly crucial to make best use of the F-35’s stealthness, firing from very long range. Moreover, integrating Meteor on F-35 is an indispensable step to move if the AMRAAM is to effectively leave british service in the near future.

The UK once planned to get rid of AMRAAM by 2017, but Meteor delays have forced a rethink. I would expect (and hope) that AMRAAM stocks will be extended a little more, to bridge the gap on the F-35, even after Meteor becomes the weapon of choice for Typhoon (should happen from 2018).

Finally, SPEAR 3 is expected to become available. Decisions regarding SPEAR 3 are expected in the coming months: MBDA is progressing with the design of the new SPEAR missile, but final development and production is expected to cost several hundred million pounds. There is a risk that the MOD will accept the Small Diameter Bomb II as SPEAR Capability 3 solution. However, this is not desiderable, as it would hurt the ability to design and produce complex weapons at home and moreover because the SDB II is a gliding weapon, while Spear has its own turbofan engine, offering greater range, greater Acceptable Launch Zone, more flexibility and greater range. All these advantages are crucial if SPEAR 3 is to provide, among others, a Destruction of Enemy Air Defence capability (DEAD) to compensate for the removal without replacement of the ALARM anti-radar missile. 

A single MBDA SPEAR missile seen on a Typhoon during development work

 

The end result the programme aims for. 2 Meteor and 8 SPEAR 3 will make for a powerful and versatile weapons load.

It becomes dubious if there will ever be a Storm Shadow integration on F-35. It won't happen that soon, and in the meanwhile the missile is aging. According to french budgetary documents, the Life Extension Programme for Storm Shadow / Scalp EG, which is a joint cooperation initiative between France and UK, is supposed to begin moving this year. We will have to see if the programme starts and how it goes. The number of missiles updated and life extended and the new OSD date will be crucial to understand if the F-35B will move on directly to the Storm Shadow future replacement. 

The SDSR 2010 imposed stock cuts on the Storm Shadow holdings for some 170 million pounds, according to the Telegraph. This is likely to have resulted in the removal of 170 to 200 missiles. Around 100 more have been used between Iraq and Libya, maybe more, leaving possibly around 600 rounds in stock. 

Brimstone is also not mentioned, at least for now. Brimstone, even in its Brimstone 2 iteration about to enter service is a rail launched weapon, so that internal integration is a problem (you need to eject the missile downwards and clear out of the weapon bay before its rocket motor ignites). However, SPEAR might include further developments of Brimstone, and if the missile continues to be the weapon of choice for CAS into the future, it will have to be added in at some point. 

Not mentioned in the table, but planned, is the addition, on the sole F-35A, of the tactical nuclear capability with integration of the B61-12 bomb for internal carriage. It does not concern the UK, but it is a factor in planning for Italy, Netherlands and, reportedly, for Belgium as it begins evaluating its options for replacing its F-16s.

Looking further into the future, the US are already planning years ahead, in particular by basing the research for new, more effective jet engines for the future on the F-135 powerplant. The future Adaptive Engine Technology Development (AETD) engine will be retro-compatible with the F-35, and is expected to bring massive advantages, in particular to combat range through much greater efficiency. The engine is expected to adapt to the various phases of flights to optimize its power output and fuel consumption. 

Funding is already being provided for cyber / electronic warfare capability insertion. In particular, a "cyber warfare" pod is in development already. Although not officially confirmed, the cyber payload will probably be carried into the TERMA-produced "multi-role pod" which is currently best known for containing the B and C's 25mm gun. 

Serious consideration is being given to directed energy weapons, in particular to lasers, but all this is of course quite a few years into the future.