Roll on Roll Off in the Sky
In our many conversations about utilising one airframe or the other to cover a broader mission set the subject of roll on roll off systems has often been raised.
There are many possibilities but the ones we have discussed most are airborne armed reconnaissance, some form of long range bomb truck and maritime patrol. The donor aircraft on top of most lists are the A400 and C130J. There are other possibilities also, SIGINT and electronic warfare/PSYOPS for example.
That is actually the most relevant question, before we even start.
The argument goes something like this;
Take a utility airframe (usually tactical transport) and use it for more than its original role, thus increasing fleet utilisation and reducing costs overall.
We live in a multi purpose world;
Arguments can be made that a dedicated device is always better than the master of none multi purpose devices.
A digital SLR camera will take much better images than the camera on a smartphone which is why professional photographers still use them but the professional photographer represents a tiny percentage of the number of people that want to take a photograph.
What you get with the smartphone is convenience and ease of use but above all, you get a reduction of cost.
It is the 80/20 dilemma, the professional needs the 20% so pays the dividend but for the vast majority of people, 20% of the cost with 80% of the functionality is a compelling proposition.
The question therefore, is a very simple one.
Can the military afford to be in that 20% 100% of the time, or, can a reduction in capability be accepted for the allure of those big savings.
I don’t have the answer and neither do I have the answer on the question of whether utilising the A400M as a Nimrod replacement would actually be cheaper but it is an intriguing question nonetheless.
Senior Scout and Harvest Hawk
This concept of roll on roll off modular system is not revolutionary, it has been done before;
In 1991, as U.S. forces prepared for Operation Desert Storm, the Air Force was busy preparing to debut a new airborne intelligence system. Aircrew operators rolled a giant gray metal box – one that looked like a railroad freight car or a shipping container – out onto a runway, where a specially-modified C-130 was waiting. The container fit snugly into the Hercules’ cargo deck and quietly came to life.
Inside that plain-looking metal box was one of the most sophisticated tactical intelligence command centers on the planet. Holding a small team of analysts and packed to the gills with special computers, antenna, sensors and processors, the box turned a C-130 into an airborne intelligence cell, capable of harvesting an ocean of critical information about the adversary, and then sharing that information with allied troops across the battlefield.
Senior Scout, as the container was called, started as a research project in Lockheed Martin’s Aeronautics division in 1986. Just five years later, it would be called into service during Operation Desert Storm. A suite of signals intelligence (SIGINT) technology built into a trailer-like unit and loaded onto a C-130 aircraft, Senior Scout allowed the United States Air Force to collect information on enemy tactical forces and quickly disseminate that information to allies in the field. Data that once took weeks to reach soldiers, marines and sailors was now available in a matter of hours.
Another quote on its performance;
On 8th June 2008 a SENIOR SCOUT crew departed Karshi-Khanaba Air Base, Uzbekistan, en route to Zabul and Uruzgan provinces located in south central Afghanistan. When they arrived they discovered the 22nd MEU surrounded by 120 insurgents. SCOUT operators quickly and efficiently passed critical intelligence to the marines. Within 90 seconds of being made aware of the danger they pinpointed three targets for tactical strikes and identified escape routes. When the battle subsided more than 80 insurgents were dead with only minor injuries sustained by the marines.
This isn’t some exotic aircraft, it is a C130 truck.
The basic concept of roll on roll off systems has been developed by Lockheed Martin with their Vigilant Hawk proposal which expands on the Harvest Hawk and secret squirrel hyper spectral imaging Shadow Harvest programmes.
There is also the Senior Scout product.
From the Senior Scout product page
Senior Scout is an intelligence, surveillance and reconnaissance (ISR) system built into a trailer-like container that can be rolled on and off C-130 aircraft. This ISR suite of equipment rapidly configures standard C-130 aircraft for tactical signals intelligence, providing capabilities that exploit, geo-locate and report communications intelligence and signals of interest to air and ground component commanders
Senior Scout has COMINT, SIGINT and ELINT operators and as the description above, the cabin simply plugs in with the antennas already having been fitted
Both Harvest Hawk and Senior Scout continue to evolve.
Crew and Systems Accommodation
Any operator consoles, computing, storage and communication equipment would need to be housed in a suitable enclosure.
Although this is not especially technically demanding it does require specialist knowledge owned by a small number of manufacturers.
Knight Aerospace in California is one such company, there are a number of others. The images below show interiors of their modules, from the luxurious to the utilitarian.
There are also a number of manufacturers of crew rest accommodation, a number of them based on palletised solutions.
Clearly, accommodating personnel (flight crew and mission specialists) in relative comfort is not be a problem, long endurance missions with multiple onboard crews would be possible with galley, toilets and crew rest facilities all within the ‘pod’
With airborne refuelling, record breaking mission endurance would enable serious persistence over an area of interest.
In smaller aircraft, cooling power hungry electronic mission equipment usually creates a significant problems, with a larger aircraft that have much greater internal volume into which to dissipate heat, this could potentially be less of an issue.
As long as the aircraft has sufficient power for electrical and cooling there should be no practical limitations to the kind of systems or mission equipment that can be carried.
Time taken to convert to role, at least for the accommodation module should take no longer than rolling in, securing in, plugging in and conduction checks.
Sensors and Antennas
It is at this point that many start sucking their teeth on the assumption that poking holes into or adding bits onto aircraft is eye wateringly expensive.
I think they have a point but there are options others have explored, doors and pods.
This is genius lateral thinking, instead of changing the aircraft skin, you just change a door.
The Senior Scout aircraft, being SIGINT focussed, has a plethora of antennae to worry about but as can be seen from the image above, the designers have managed to keep them clustered onto components that can be changed relatively quickly.
Changing the undercarriage and paratroop doors is said to take no longer than 15 hours.
In previous posts both Martin and I have looked at the demountable options provided by Airdyne, as a recap.
The LC-130 ‘Skidbirds’ from the 109th Airlift Wing of the Air National Guard have been providing transport facilities to Antarctic stations for decades. There had been a number of aircraft losses due to undetected crevasse formations in the landing and take off areas so in 2006 the New York Air National Guard funded a programme by Sandia Labs to study an X-Band ice penetrating radar that could be mounted on its aircraft, principally the LC-130’s and Twin Otters then used for airborne ice field landing site reconnaissance, prior to landing.
Airdyne created a system that replaced the door with a pylon and integrated operator console.
What this project did (that is related to this post) is prove that a payload pod could be carried on a door mounted arm or stub wing. The benefit of using the paratrooper door is that if the aircraft is unlikely to be recreating the Arnhem landings then the door is somewhat surplus to requirements and represents a decent attachment point because it negates the need for complex airframe integration and can be easily swapped in and out as needs dictate.
It was, and is, is an ingenious solution.
Their main product is called SABIR (Special Airborne Mission Installation and Response) and it has a number of components, mounting solutions, integral operator seats, workstations, tube ejectors and the pods themselves.
These choices allows the user to mix and match depending on requirements and because there is no airframe modification they can be tested/integrated off board at a low cost. Various workstations, observer/operator seats and equipment racks can be fitted to the pallet. The pods themselves are attached to the swing arm with it being raised for take-off and landing and lowered when airborne.
Airdyne have a good description for the pods
In essence, SABIR pods are similar to smart phones – all you have to do is select a pod and add your sensor application. Because the pod form factor is already flight rated, customers save cost and schedule by only having to focus on what goes into the pod.
Multiple SABIR systems can be deployed on the same aircraft to maximise sensor variety or ability to observe multiple locations.
The A400M paratrooper door was subject of a great deal of test and modification during the aircraft design phase so this approach would probably not work as well and looking at the A400M door below it is immediately apparent integration would be more complex.
The basic point remains, door mounted solutions are possible, although perhaps not for complex or bulky sensors on the A400M.
If a side door pod option is less viable for these larger sensors (as opposed to antennas) the aircraft does have two, very large weight capable, plumbed in wing hardpoints.
Which brings us on to the subject of pods.
Putting sensors in pods is pretty much common or garden run of the mill stuff these days, any number are available off the shelves of a number of different manufacturers.
It is not even new.
The SAMPSON pod, amusingly called the Special Avionics Mission Strap On Now, was developed in the mid-eighties and flown on the High Technology Test Bed (HTTB) aircraft.
SAMPSON was based on a 1,360 gallon external fuel tank modified to take a range of avionics and sensor equipment with a ram air turbine providing the power. Instead of copper cabling the data link used an infra-red transmitter on the side of the pod and a receiver inside the aircraft looking through a passenger window.
It was much like a TV remote control although as the picture below shows, rather larger
The SAMPSON pod was used for many years by to support the Open Skies initiative, click here for a good read on this fascinating subject.
What does this trip down memory lane show, nothing really, apart from the simple fact that mid eighties engineering and systems integration found a way.
Designing and manufacturing sensor pods is not a trivial task but it is not rocket science either and there are organisations out there with the experience and skills to do it.
The US Harvest Hawk programme has demonstrated podded sensors on a large transport aircraft.
Harvest Hawk is an eminently sensible programme driven by the USMC, started in 2008/9, that seeks to squeeze maximum benefit from a common platform, using roll on roll off kits including podded sensors and weapons that extends the capability of the C130 tanker to include gunship and surveillance.
Defence Industry Daily has maintained a very comprehensive page on the US Marines Harvest Hawk, click here, well worth a read, plenty of great information and images.
Lockheed Martin are proposing a step forward from Harvest Hawk with Vigilant Watch and Vigilant Stare, all variations on the SABIR/SAMPSON podded sensor theme.
Lockheed Martin and Airdyne are joined by a number of other manufacturers with sensor pods, everything from the complex Gorgon Stare to the relatively simple Moog ProtectIR pod are available somewhere one someone’s shelf.
In fact, when you think about the size and weight of modern sensor systems it is hard to imagine anything that you couldn’t put in one, the very large radar systems perhaps, but beyond that, not sure.
The radar planned to be fitted on the A400M is the Northrop Grumman AN/APN-241 Tactical Transport Radar, the same as fitted to the C130J and C295. This might not be best suited to the maritime patrol role where something like the Selex Seaspray 7500 or Elta EL/M 220 would be more appropriate. This radar was selected by the US Coast Guard for their Hercules HC-130H upgrade programme, it would not be an insurmountable challenge to swap out the APN 241 should it be required and we already have in service members of the Seaspray family of radars.
An Elta EL/M 220 radar as fitted to numerous maritime patrol aircraft, again less than 100kg
Click here to read an Airbus presentation on SAR radar
An airborne AIS transponder and display would allow the crew to take advantage of ships identification transponder information. Even pod mounted searchlights are available off the shelf (we could always reuse those off the Nimrods) and an observer window in the paratroop door might also be possible at very little cost.
Into a standard pod architecture you could snap in combinations to suit, an overland pod might major on multiple electro optical turrets and extensive communications. Instead of the usual single EO turret, a podded solution could easily have 3 or 4 and with something like the BACN communications node.
I like the idea of evolving the capabilities of the aircraft through off-board pods because it allows them to be developed, tested and delivered at its own pace, minimising aircraft downtime and maximising efficiency.
Think of the possibilities.
What was that about payloads not platforms!
Weapons and sonobuoys…
If sensors were a tricky problem then releasing weapons and other stores is even more so, especially at higher altitudes.
Weapons designed for essentially, firing straight off a fighter pylon, might easily be adapted to be thrown off a ramp.
For sonobuoys, doors may again be the answer.
Our friends Airdyne has an adapter for releasing single sonobuoys throgh a specially adapted paratroop door.
Sonobouys are launched at low and high altitude but the same basic system from Airdyne would be suitable for both.
Nimrod had two rotary dispensers and two single compartment pressurised launchers with storage racks for extra. A door mounted sonobouy dispenser with additional storage elsewhere in the aircraft would at least on face value offer a solution. Telemetry and receiving systems, from Ultra Flightline, would need to be fitted as well.
The problem with this is the accurate dropping of multiple sonobuoys in a pattern, a single tube may not provide the density needed.
A rotary ejector may be adapted for use with such a door mounted arrangement or use could be made of already engineered solutions like the airborne refuelling centreline system.
If this is not possible a pod could be used.
A typical A size sonobuoy weighs approximately 15kg, with a payload of 400kg, a pod would be able to carry many.
Weapons provide similar challenges but are generally larger and more sensitive to release configuration. Brimstone missiles for example, need to be fired from the pylon, they do not drop and then fire their motor, as can be seen in this image.
Using Brimstone would therefore require open carriage on a pylon, not a problem in itself of course but worth noting.
Other systems such as the MBDA Viper Strike have been launched from ramp adapters and the Harvest Hawk Derringer Door
There are a number of emerging low weight freefall munitions such as the STM, MBDA Sabre and even a freefall LMM might fit the bill.
SPEAR Cap 3 is designed to be freefall launched from the F35 bomb bay, another future possibility.
An interesting development is the use of decoys and decoy jammers as part of an attack plan against complex integrated air defences.
Raytheon are currently marketing their MALD and MALD-J, both evolved from the earlier Air Launched Decoy ADM-160A.
The Miniature Air Launched Decoy (MALD) is used to lure enemy air defence systems into revealing themselves or attacking aircraft or ISTAR systems that can provide targeting information for stand off weapons. With a range of 500nm, endurance of 45 minutes, operating altitude of 40,000 feet plus, speed of Mach 0.91, modular electronics fit and emissions signature that is designed to mimic allied aircraft it can also be used to simply overwhelm air defences with targets, if they attack MALD they are depleting their finite missile stocks.
My friends over at Defense Industry Daily have another great write up on the history and contract aspects of MALD, click here to view.
They report that costs have risen to $120k each, which seems like excellent value for money to me, compare that with the £70m plus cost of a Typhoon and the likely £100m plus cost of an F-35M and the economics become very attractive. After some initial reliability issues it is now entering service with the USAF.
MALD and MALD-J have also been designed for carriage on aircraft carriers and unlike many complex systems was developed and delivered under budget.
As can be seen from the video above, MALD and MALD-J can be launched in significant quantities using transport aircraft like the C17 and C130. This is called the M-CALS or MALD Cargo Aircraft Launch System
It is an elegant and cheap way of launching decoys in quantity and at low cost.
M-CALS can be stacked so that on a single pallet, 8 decoys can be carried and launched. If more are required the MCALS launch pallet is simply discarded and the next in line positioned. In aircraft like the C17 that can carry two pallets wide, more can be launched without ditching the launch pallet.
It was also reported in 2009 that the UK had shown an interest in MALD but this self evidently went nowhere.
I quite like the concept of using expendable decoys and if the UK is ever to go against, as the phrase goes, anyone armed with slightly more effective weapons than a sharpened mango, they may well be essential.
Traditionally, anti aircraft missiles are much cheaper than the aircraft they are designed to destroy, the economics are in favour of missiles. Although it is a mono syllabic simplistic argument, if a missile costs a million each and an aircraft costs a hundred million, the exchange rate favours the missile. Reverse that, where the aircrafts surrogate costs less than the missile, the economics of the exchange becomes interesting. Enemy forces will always have a finite stock of anti aircraft missiles at the point of attack and the more expensive long range varieties will also not be available in large quantities. Luring enemies into expending those scarce and expensive missiles at decoys is a cheap way of degrading their capabilities relatively safely.
The numbers favour the attacker.
It is of course not as simple as that but decoys are an interesting alternative to the relentless cost increases of stealthy aircraft, or at least a means of complimenting their survivability.
If it is demonstrably possible to launch the 120kg MALD-J the smaller SPEAR CAP 3 should be possible.
In addition to pylon mounted Hellfire missiles the USMC Harvest Hawk has had considerable success with the Griffin missile, again using a door or ramp mounted launch mechanism.
The video below shows both Hellfire and Griffin in action
The ramp mounted mechanism is much like MCALS, from Plasan
The latest AC-130W has also been cleared for GBU-39 Small Diameter Bomb carriage.
Whether launching a 250Kg Stingray torpedo would be possible using something like the Gunslinger of MCALS system is unknown, it is only physics after all and we seem to manage ejecting torpedoes from frigates using compressed air.
Other payloads could include unmanned aircraft, Boeing have proposed an air launched unmanned aircraft, the Dominator, for example.
And another option for launching unmanned systems
Perhaps we might even see a use for Fire Shadow in this role, now that would make an interesting concept, an unmanned loitering munition being launched and controlled by a loitering manned aircraft.
Going up in weight we might also consider launching Storm Shadow stand off cruise missiles.
Currently, Tornado (and soon to be Typhoon) is used to launch these sophisticated 1,300 kg missiles, two per aircraft.
Consider this for a moment.
With a maximum altitude of 40,000 feet and cruise speed up to Mach 0.72 the A400M Atlas can fly in regular civilian airspace.
Testing is confirming that the aircraft has excellent aerodynamic performance and very stable in normal flight but extremely agile for such a large aircraft. It has been noted that this aerodynamic stability and clean air flow over the rear of the aircraft will allow some interesting thoughts on payload delivery to develop, launching UAV’s and cruise missiles looks less like a load of nonsense now!
In addition to the excellent handling characteristics and speed its range is quite impressive.
As a thought experiment, assume that having the missiles on the same platform does not seriously impede the fire plan (target separation etc), the threat profile is such that it can approach the launch point without escort and that the A400M is carrying 8 Storm Shadow missiles, roughly 10 tonnes.
Now those are some reasonably large assumptions, which is why I am not advocating this as a replacement for Storm Shadow Typhoon integration but…
10 tonnes provides about 4,500nm range or 2,250nm radius (divert locations and other factors all being equal)
The map below shows a crude 2,250nm and 4,500nm radius around Brize Norton e.g an unrefuelled round trip and a refuelled round trip
So how could you launch Storm Shadow from an A400M?
Te FOAS study from a while ago looked at options for launching from a pallet from a C17
MBDA have actually proven the concept with the Taurus cruise missile
Skip forward to the 1:59 mark on this video and watch the Taurus T being launched off the ramp of what looks like a Transall
MBDA state that a C130 can carry 12 missiles.
With a ramp loading capacity of 6 tonnes, the A400m should have no problems with any of these stores combinations.
The simplest form of releasable payload are things like liferafts or medical supplies, two examples below from the Irish Army Air Corps and US Coastguard
Pretty simple integration, they are thrown off the ramp :)
Just to prove that there is nothing new in this world, a handful of videos showing air launched missiles and unmanned aircraft.
I have defended the RAF’s long range strikes against Libya because they demonstrated perfectly a prompt strike response capability against difficult targets and when Tornado retires that capability might well pass to Typhoon or maybe (an outside chance) the F35B.
But imagine a repeat scenario in the mid 2020’s with an A400M Atlas based delivery option, no airborne refuelling, multiple launches, loitering for hours in response to changing target conditions or post-strike assessments and a fraction of delivery cost in comparison.
What makes this interesting, in comparison with C130 options, is the A400M’s speed, space and range, it makes the arguments against a little more tenuous.
I don’t want to get too carried away with notions of hoofing Storm Shadow off the ramp of an A400M but food for thought nevertheless!
For other missions there are endless combinations of sensor, crew and weapon, most of them already proven in practice, if not principle. Then combine with an aircraft with the speed, payload and reach of the A400M Atlas.
Maritime patrol, PSYOPS, SIGINT, persistent and armed ISTAR, SF support, area denial, airborne communications relay and command post
Back to the original question of why bother.
Tough one, simply because the answer would come out of a very large spreadsheet that none of us have the first clue about, i.e. it is all about the cost. The cost benefits of reducing types in the fleet (training, simulators, spares etc) against the cost disadvantages of developing this stuff and putting it into an already too small fleet of aircraft like A400M. No one is suggesting that you could be air dropping supplies one day and doing a spot of sub hunting in the North Atlantic the next, semi dedicated aircraft would still be the order of the day. But by operating out of a larger pool of aircraft with conversions times of a couple of days you mitigate against lower availability caused by all manner of incidents when you have a small fleet.
Large fleets of fewer numbers of aircraft is relatively speaking, the optimal way forward for a cash strapped nation.
You might have to accept some performance compromise, am not saying an MPA A400M would be as good as a P8, but can we accept a reduction on individual capability for benefits across the wider force.
It boils down to exquisite platforms built to exacting standards but available in diminishing numbers versus something not quite as good but available.
That 80/20 question.
The options are there.
Imagine the possibilities.