Return of the airships?

The Royal Navy has not had any airship for a long, long time now, but not so long ago the national  press reported that Hybrid Air Vehicles which is under contract to build the Long Endurance Multi-intelligence Vehicle  surveillance airship for the US Army, had started talks with the Royal Navy.

At the time the report caused quite some surprise and excitement. Of course, i wasn't excluded. I reported about the possibilities rather extensively in the past, but i also reported about some of my doubts and issues with the concept.
In particular, i was puzzled by how such a massive airship would be sustained during long overhead surveillance operations far out at sea. With the limited information available at the time, i was worried that the airship probably would need a dedicate support vessel in order to be able to stay out at sea for a long time. Maintenance, refuelling, topping up of Helium, were all challenging aspects, considering that the Airlander 50 is more than 120 meters long, and perhaps 65 meters wide. You can't land it on a ship, not even on CVF. Yes, it lands on water, but when it is landed, what kind of maintenance does it need? What kind of impact the weather and rough seas will have on the ship once it lands in the water? Will it be possible to moor it alongside a RFA vessel, or another ship, and service it safely that way?

These were some of the questiones that immediately came up to me. 

Now, the Airlander 50's page on Hybrid Air Vehicles' website has been updated to include a few interesting details that partially answer mine (and, no doubt, the Royal Navy's) questions.

Hybrid claims that the Airlander 50: 

With proven low vulnerability and ability to land on water, the Airlander 50 can be maintained from on-board for an extensive period – up to several months. It is crewed and operated like a ship; crew are permanently embarked, and it is designed to accompany task forces as a unit in its own right. AIRLANDER 50 can take fuel from ships using helicopter in-flight refuelling (HIFR) facilities, load stores, food and change individual crew members if required. 

Its use with a maritime task force is something between a number of freight moving helicopters, RFA ships freight and people movement between forward mounting bases and the task group, then delivery around the task group, and even surveillance if required. With a capability to lift 20 tons vertically, AIRLANDER - 50 can be used to transfer exceptional loads between ships at sea. In assault operations, AIRLANDER can be used in support, releasing other assets, such as helicopters, to be deployed elsewhere.

This is a new information, and particularly relevant. The capability to deploy with a naval task group and stick to it, staying with the ships, is crucial to making the airship a truly useful ISTAR platform. If it was effectively demonstrated that the airship could deploy and stay out at sea with the fleet for at least 160 to 200 days, then the airship would truly be an alternative to helicopter-based CROWSNEST solutions. The airship would be a very good AEW and EO/IR surveillance platform in that case.

My doubts actually were not so much about fuel, but more about more complex and "exotic" things such as topping up of Helium, something the current warships do not do and are not kitted for, but Hybrid's claim reassures me that the problem is far from unsolvable. At least in theory.
The airship is described as having an endurance of 5 days at 16.000 feet if a human crew is on board, while it can stay in the air for a surveillance mission for up to 21 days at 20.000 feet, at an operating radium of 500 nautical miles if remotely piloted. 

With its ability to land on water, and take fuel aboard while hovering like an helicopter behind a warship, the Airlander 50 should thus be genuinely sustainable in the long term during a deployment far away from home out at sea.

In Carrier On-board Delivery (COD) role, the airship has a very interesting capability: it comes fitted with a very powerful crane that can vertically lift or lower a 20' container, loaded to a total weight of up to 20 tons.
This makes the airship a truly unmatched heavy lift asset. Sure, huge as it is, when the airship hovers over the back of a CVF to carefully lower a heavy load on deck, the air operations will be seriously affected, but the capability is very, very interesting.

The payload area of the Airlander 50 is sized to take 6 20' containers in two rows of 3 each, sitting abreast, for a total payload of 50 tons. There is also a secondary cargo area, 2.8 m high, 3.93 m wide and 10 m long, which can prove very useful for many uses, including providing a rest area for the human crew when present.
The containerized cargo area is particularly useful, as almost anything can be built into containers, and an airship like this could deliver a small but effective containerized hospital directly to a disaster struck area or rear line in exceptionally short time, and/or deliver workshops and Fitter Sections directly from the amphibious ships to the front line. For example, the british armed forces already have a series of containerized medical facilities including shelter-mounted CT scanners, 44 container workshops and REME repair posts. 
Deploying containers by air, vertically and without the need for an airport, is in itself an immense operational advantage.

Another interesting aspect of the Airlander, which i suspect is however still largely to be explored, is shown in one image from Hybrid, in which an airship can be seen towing a sonar in the water. It would be interesting to explore this aspect further, because such an airship could be an excellent ASW weapon and a good maritime patrol aircraft, with an important operating radius. The Airlander is said to have a range of 2600 nautical miles (not clear if it is at full 50 tons payload, however). Of course, flying low over the waters to search for submarines and tow a sonar curtain will have a big impact on the operating radius, but it should nonetheless remain impressive.

There are surely aspects and procedures to be studied and determined, but the use of Airships in support of military operations, including at sea, promises to deliver serious advantages.
It is definitely an area where i'd like to see the UK investing. I think there is room for achieving great results.

Giving eyes to the aircraft carriers

I will start this article by making it clear that I deem extremely unlikely (unfortunately) the scenario that sees the UK buying the V22 Osprey, fascinating and militarily attractive as this solution arguably is. I don’t think the MOD has the money, the will and perhaps not even an impelling enough necessity for doing it. It is a lot more believable, instead, to talk about the US Navy exercising its option for the buy of 48 Ospreys, to use mainly for Carrier On-board Delivery (COD) and, eventually, Search and Rescue (SAR) and Air to Air Refuelling (AAR). And, perhaps, at some point the US Marines will want an Aerial Early Warning platform capable to operate from the flat-deck amphibious vessels, who knows.

With the return to the F35B and, as a consequence, to a STOVL-configured CVF, rumors have been prone to come up every few minutes about the UK possibly buying a number of Ospreys for AEW and COD and AAR roles. Not without a reason, since the V22 AEW was a contender in MASC (Maritime Airborne Surveillance and Control) for the replacement of the Sea King ASaC Mk7 AEW, with some interesting collaboration going on between the UK and the US Marines, who showed quite a bit of interest in fitting the british Cerberus AEW suite to the Osprey. In addition, the Royal Navy was pretty eager to demonstrate that it would be able to operate with an airplane as large and complex as the V22, even on a deck as “small” as that of an Invincible-class carrier.

A lot of things have changed, however, and not for the best. MASC has become Crowsnest, and it is now pretty much certain that the new AEW solution will be Merlin HM2-based, with the helicopter being fitted with the Cerberus system, migrating from the Sea Kings, or with the new Lockheed Martin Vigilance podded radar system. A marked backwards step from the earlier Navy hopes of procuring around 10 dedicate AEW platforms: under the new scenario, the already hard-worked fleet of Merlin helicopters, while going down from 42 (4 in storage) to 30, would be loaded with yet another role, in addition to ASW and Maritime Security in the Gulf.

Even worse, there is a very real risk of having to face and AEW gap of several years, with the Sea King Mk7 bowing out in 2016, with the replacement only available possibly as far away as 2021 or 2022.

From this scenario to a buy of V22s for specific navy use… well, I think it is evident why I find it real hard to consider the Osprey option anything other than a nice dream. However, it is a subject worth treating, and, who knows, perhaps I’ll be proven wrong.

I’d love it.

AEW, AAR, COD  

The core role that needs to be met, urgently and categorically, is the Airborne Early Warning one. The Falklands have well shown what happens when the surface ships are left on their own, trying to react timely to airstrikes that their mast-mounted radars can only detect at short distances. Highly deployable airborne radars capable to provide the commanders with a complete picture of what’s happening in the air and on the surface have proven relevant and indispensable in many, many more occasions: name a recent conflict the UK has been a part of, and the Sea King MK7 was there.

It was there in 2003 to provide 3^rd Commando Brigade with the necessary airborne surveillance capability. It was there in Libya, it was there to protect the Olympic games and it is used to great effect in Afghanistan.

Crucial to the Sea King MK7’s success is the Cerberus system, with the Searchwater 2000 radar. This system, delivered from 2002, turned the Sea King MK2 (a pure AEW platform) into a multimission surveillance and control system: the Searchwater 2000 is a very capable radar that can track targets on the surface and in the air, processing three radar modes at once.

The two observers flying into the Sea King MK7 can share the battlefield picture obtained thanks to the radar with the commanders on ships / on the ground, via Data Link 16 and an extensive Secure Communications equipment.

In any moment, the Observers can be asked to re-task, and look over a particular area. For the almost totality of a typical 3.5 hours sortie, the Sea King MK7 is an all-seeing eye over the battlefield.

There is no exaggerating the impact of this kind of capability.   

The radar, multimission by nature, makes the Sea King better, under certain aspects, than an immensely more expensive, much bigger E3D Sentry: the AWACS has very little use as a ground-target tracking platform.

In addition, the small sizes of the Sea King, and its ability to take off vertically have been important, making its deployment a lot easier when compared to the use of huge E3D Sentry and/or Sentinel R1.

On the other hand, the Sea King’s typical sortie lasts a fraction of that of a Sentry or Sentinel, and the helicopter can only fly at a much, much lower altitude. And there’s a price to pay for this: the radar has to be placed as high as possible, as altitude means increased range, and increased range means detecting the enemy earlier, and having more time to react. And time is never enough in certain situations. Every additional second counts.

Delivering 24 hours coverage with the Sea King is not easy. The MK7 will often fly two missions a day, but even so, you need no less than 4 airframes to ensure constant coverage. And there is no remedy to the altitude issue.

These two being the reasons that make the V22 attractive.

The V22 is fully compatible to a STOVL carrier, and is almost as deployable as Sea King: it does not need big runways to operate. On the other hand, it is much, much larger than Sea King, so deployment on small ships such as frigates and destroyers is a no.

On the other hand, the V22 offers greater mission endurance and flies at a much higher altitude, with a service ceiling of 24700 feet. A Merlin-based solution would fly at 15.000 feet at most.

The MV22 is also much faster, at between 250 and 262 knots maximum sustainable cruising speed against Merlin’s cruise speed at 150 knots. Even in “economic” cruise speed, the MV22 would undoubtedly lead by a great margin.

The MV22 has at least 4 hours endurance with a load of 24 combat-ready troops, but its mission normally is not described much in terms of endurance, but in terms of range and speed: it can carry the 24 Marines out to 325 naval miles and return to the ship in record time.

The Special Forces CV22 has additional fuel tanks, and its mission is to carry a 18-man team out to 500 naval miles.

In March 2008 Boeing was already proposing a V22 ASaC solution which would incorporate the CV22 additional fuel tanks, improved power connectors, secure communications and a Link 16 antenna. A rigid radome would contain the Searchwater 2000 radar. As of 2012, the proposed V22-Cerberus is still mooted, as Totally Organic Sensor System (TOSS).  

The US V22 plan calls for the acquisition of 458 V22s, of which 360 for the Marines (MV22 variant), 50 for the US Special Forces Command, via USAF (CV22) and 48 for the US Navy (HV22). As of 2010, 216 Osprey aircrafts had been procured, 185 for USMC and 31 for USAF. The 48 Navy Ospreys haven’t yet been ordered.

Recent buys have been conducted under the terms of a 10.4 USD billion contract signed on March 28, 2008, valid out to FY2012 and covering procurement of 141 MV22 and 26 CV22, giving an average cost per unit of roughly 62,3 million dollars for the multiyear contract. When the over 10 billion dollars of Development costs are added, the unitary cost is 109 million each over the planned 458-strong fleet.

The V22 is not a cheap airplane. However, it is worth remembering that the UK is paying for 14 new Chinooks a billion pounds (including 5 years of support), and that means north of 100 USD million per airframe.

In terms of capabilities offered, a MV22 AEW would mean a big leap forwards, thanks to greater speed, altitude and endurance. Besides, the Osprey can refuel in flight, and while the Merlin (the HC3 variant, at least) can also be air refueled, the UK currently is unable / unwilling to exploit this particular characteristic.  

The TOSS envisaged 3 workstations on board, adding one compared to Sea King MK7, and better accommodating teamwork with UAVs, that the UK has been experimenting as part of MASC since 2005. Namely, the Sea King MK7 was back then trialed working in team with the Scan Eagle drone, which the future AEW platform could send ahead to visually observe a target acquired on the radar, for example.

This year the Scan Eagle will again be trialed by the Royal Navy from a Type 23 frigate, but this time it’ll be an operational trial, since the drone will be used in the Gulf, during a routine deployment.

An April 2012 image of a possible V22 ASaC shows two workstations, but probably there is quite a lot of flexibility in how the AEW equipment can be arranged on board.

The AEW Osprey is shown equipped with a palletized Cerberus, rather similar to what was proposed in 2010 by Thales and AgustaWestland for adoption on the Merlin HC3. The radome containing the Searchwater radar is lowered out from the rear ramp, while a pallet fitted with the electronics and workstations

As a Carrier On-board Delivery platform, the V22 offers respectable performances: it has an internal cargo bay volume of 739 cubic feet, and can carry a 20.000 pounds load, with the floor rated for a pressure of 300 pounds per square foot.

The length of cargo space available is 20.8 feet, which means a load of, for example, four 48x48 Warehouse pallets, or two 463L pallets. The cargo space can take containers as large as 68 inches wide, 66.23 inches high, and 250 inches long as long as they can achieve the necessary restraint criteria.

For external loads, there are two cargo hooks, either of which can support a 4358 kg load (10.000 lbs). Alternatively, both hooks can be used together, to stably lift a 15.000 lbs load.

There is also a rescue hoist on a removable boom. Good for SAR work, it is rated for 600 pounds. Fastrope equipment can be fitted under the tail, allowing men to rope down from the rear ramp with the Osprey hovering.

As an Air to Air Refueler, the V22 is fitted with a palletized 660 lbs kit with a single drogue unit, deployed centrally from the rear ramp. Two auxiliary fuel tanks are installed in the cargo bay, each for 430 gallons, for a combined 5590 lbs of weight.

The installation of this kit takes around 1 and a half hours. Max speed is 230 knots in this configuration, enough to safely refuel fixed-wing jets, F35 included. The central position of the drogue keeps the plane that is being refueled safe from the vortexes of the two massive rotors of the V22.

Internally, the MV22 carries 1720 gallons (117000 lbs), with the CV22 carrying 2040 gallons, so that, with the auxiliary tanks installed, there’s at least 17290 lbs of fuel on board, much of which is transferable.

It is not much, when you consider that a F35B carries more than 13.000 lbs of internal fuel, but for sure it is enough to provide an helpful top-up to several F35s in a single sortie, extending their range and endurance considerably. 

The ISR-C2 variant shown seems to be equipped with the TOSS system based on the Cerberus and Searchwater radar. The trademark "bag" of the radar is well visible.

The deck footprint of a V22 is quite huge: 84,6 feet in width and 57,3 feet in length. When folded for storage, however, the width reduces to just 18,11 feet [5.8 meters], while the length increases to 63 feet. The V22 can be brought down into the CVF’s hangar without being folded, as the lift and hangars are big enough to take the airplane. The hangar is also high enough, at least for part of its length, to take the unfolded V22, which is 6,7 meters high, reducing to 5,5 meters when folded down.

If the UK ever got around to buying the Osprey, there would also be an opportunity for collaboration and joint maintenance in the UK, as the US are deploying a squadron of CV22 Special Ops Ospreys to the airbase in Mildenhall.

There is no doubt that the V22 would make available some very interesting capabilities to the Royal Navy, but at a quite high cost. I don’t think the Navy will ever be able to justify said costs. To the scrutiny of the MOD and Treasury, the Merlin helicopter is probably going to result perfectly adequate for the AEW role, and COD and AAR roles are not immediate requirements, much as they would of course add a lot to a carrier task force’s capability. 

Data from: 

http://www.scribd.com/doc/89698817/v22-brief#download - thanks to SNAFU - Solomon for putting this online 

http://www.marines.mil/unit/mcbjapan/Pages/Around/MV22GB.pdf

Arnie Easterly (January 2004) "Navy V22 Concept of Employment, US Naval War College" 

 

Crowsnest: the Merlin AEW

Indeed, as said also in the Royal Navy 2012 handbook, the Crowsnest is by now set on using the Merlin HM2 platform as base for the AEW role.

The HM2 is the soon to be in service upgraded variant of the Merlin HM1 sub-hunting helicopter. Originally, 44 Merlin HM1 were purchased, but in the years 2 have been lost to accidents and 4 have been mothballed. Of the remaining 38, 30 are being updated, while an option for modernizing the other 8 seem set not to be exercised.

The Merlin HM2 fleet will routinely be asked to provide 6 or 8 Small Ship Flights for the Type 23 and then 26 frigates, with more potentially earmarked for Type 45. A requirement also exists for providing larger (4 to 6 helicopters) flights to big ships such as RFA Argus (it has become a common solution for Somalia anti-piracy deployments) or the Fort class replenishers, and of course to the Aircraft Carrier in future. Then there are additional security tasks, training needs and other requirements to be met.
If we consider that all ship flights ideally should be triple (one training, one deployed, one recovering after deployment), we can immediately appreciate the full dimensions of the problem, and of the work that the already stretched Merlin family does. Meet all calls from a fleet of 30 aircrafts will be a real problem.

As I said, I deem it highly unlikely that we get an Osprey solution. My greatest hope is to see Crowsnest adjusted to involve the upgrade and use of the 8 – 12 HM1 airframes not currently part of the HM2 upgrade. This upgrade could do away with everything relating to the dipping sonar and sonobuoys, and focus on delivering the core software and hardware modifications of the HM2, to remove obsolescence and make the fleet logistically common to the main one. This way, the two AEW Squadrons could be retained as a separate force, like now, and the requirements could better be met.  

If we were to obtain this, it would already be something worth cheering for.

There are two different industrial teams putting forwards two modular AEW solutions for adoption on the Merlin HM2. One team is composed by AgustaWestland and Thales, and includes a palletized Cerberus solution, “migrated” from the Sea Kings.

Lockheed Martin and Northrop Grumman are putting forwards their Vigilance podded radar/ESM solution, developed specifically on the HM2 software and systems, which are a Lockheed product to start with.

In some more detail:

Thales and AgustaWestland proposal

The initial proposal by Thales and Westland was made in the summer of 2010, and aimed at HC3 type Merlins equipped with a rear ramp. The choice of airframe was rather weird, as there is no overabundance of Utility helicopters, quite the opposite!

The possibility of modifying the surplus HM1 airframes to cut a ramp opening into their back was, as far as I’m aware, never confirmed, and anyway such an approach would require quite a lot of work and expense. Westland at the time was planning on the hope that the MOD would acquire around 10 new helicopters specifically to meet AEW needs. 

The original Thales - AgustaWestland proposal, targeted at the Merlin HC3 (or better still at new build "HC3+" with folding rotors and navalization)

In this first proposal, a pallets with two workstations and the electronic equipment would be rolled into the fuselage, followed by another pallet mounted on the edge of the ramp, holding up the Searchwater 2000 radome, which would be lowered once in flight to have unobstructed 360° coverage.

In 2011 the Thales/Westland proposal evolved as it became clear that HM2 airframes would likely to be mandated for the job. The new proposal removes the need for a rear ramp and for pallets, by utilizing modified HM2 workstations (2 of them, no additions) and by fitting a modified Searchwater radome over rails fitted to the side of the fuselage.

The radar pod would slide up and down the rails: up to clear the way for landing, and down to obtain unobstructed view once in the air. 

The revised Thales proposal, with rail-mounted radome. The "bag" slids upwards prior to landing.

This new proposal involves minimum modifications to the base helicopter, and would enable quick re-roling of the Merlin if most or all of the HM2 fleet was fitted with the rails and software mods.   

Lockheed Martin and Northrop Grumman proposal

The Lochkeed Martin/Northropp Grumman Vigilance AEW radarpod is a 280 to 300 kg pod, entirely self-contained, which houses a powerful Northrop Grumman AESA radar, said to be related to the AN/APG80 and AN/APG81 radars of the same company. The AN/APG81, in particular, is the “super radar” of the F35.

Said AESA radar is said to offer quite unbeatable performances, with SAR and ground targeting capability, and powerful air to air AEW mode.

The Vigilance pod also contains the processor and power system, an IFF interrogator, GPS/INS, ESM sensors and its own cooling system. Two of these pods, mounted on the torpedo hardpoints of the Merlin HM2, can give 360° degrees of AEW and land surveillance capability. They only need a single power source connection, and can work with the software and tactical workstations (2) of the Merlin HM2, even if two more stations could be added for improved performance in the various roles made possible by the multimission nature of the radar. 

The Vigilance radar pod fitted to a Merlin HM2 for tests

The Vigilance pod contains IFF, AESA radar and integrated cooling system

Again, this solution requires minimum modifications to the helicopter (very possibly even less than required by the Thales solution) and would be quickly adoptable on potentially all of the HM2s.

The Vigilance pods could almost certainly be fitted to the V22 as well, leaving more space in the cargo bay to install auxiliary fuel tanks and expand endurance. The pods are indeed offered for adoption on a huge variety of rotary and fixed wing platforms. Validated on the Merlin HM2, the Vigilance is offered for platforms all the way up to the C130.

The odd and fascinating one

News of Royal Navy interest in hybrid airships surfaced on the press some time ago and generated immediately quite some interest.

The Bedfordshire-based Hybrid Air Vehicles is producing its HAV304 airship platform for the Northrop Grumman’s Long Endurance Multi-Intelligence Vehicle (LEMV), an airship that will offer the US Army a 21 days loiter time at 20.000 feet (plus possibly the equivalent of 2 days loiter in range of deployment), with a wide range of sensors and cameras installed as part of a 1800 lbs payload.

With a crew of men onboard, loiter time reduces to 5 days at 16.000 feet.

The hybrid airship can loiter at 30 knots speed and cruise at a max speed of 80 knots.

The LEMV has made its first flight in the last few days, some 16 months behind schedule: it had to be in Afghanistan by the end of 2011, and it won’t be there before 2013.

The Royal Navy interest was apparently for the HAV314 variant, however, a larger heavy lift airship with a payload of 50 tons. Now known as AIRLANDER 50, this hybrid airship can land on water or on any reasonably flat ground surface. It does not need a runway, but it does require around 4 times its length in open space to safely land and take off.

Range is 2600 nautical miles (at full payload of 50 tons?), and the body of the airship is fitted with a cockpit for a 2-man crew. The cargo area is separated in two zones: the first area, just behind the cockpit, has a raised floor and offers 2.8 meters (9 feet) in height and 10 meters (33 feet) in length, with a minimum width of 5,64 meters. The second cargo section offers 3.93 meters (13 feet) in height and 20 meters (66 feet) in length and can take 6 standard containers in two rows of 3. In the rear, a vertical crane assembly is provided, which can lift 20 tons, and pull up or lower a container on a truck or on the ground.

Landing and take off speed is 40 knots, and cruise speed is around 80 knots or higher. 

With 200 passengers, it can cross the Atlantic in around 36 hours. According to the Telegraph report, the Royal Navy was even considering the Airship as an assault vessel, carrying up to 150 Royal Marines and a number of RHIBs that could be lowered into the water via crane, or deployed after landing the airship on the water. Fascinating, even if I wonder what the range and endurance would be, what kind of accommodations the Royal Marines would have on board and what exactly would be the mission of such platform.

As an AEW/ISTAR platform, an airship is both attractive and problematic: how would it deploy? Self-Deploying at range over a naval task force in open sea might be a real issue, and the airship definitely can’t land on the carrier’s deck, even less on a smaller vessel.

Would it be possible to refill, maintain, refuel and support the airship by landing it on the water, or would an airship-support vessel be required?

With an airship costing 60 million pounds, reportedly, the solution is already far from cheap, at least in initial procurement (the savings come over the service life of the platform, which requires a lot less support and a lot less fuel than helicopters and airplanes), without needing to buy a (huge) support vessel capable to embark at least a couple of airships, the number needed to ensure continuous coverage.

Even assuming that a Cerberus-like payload can be integrated, and then operated remotely from on board the carrier to maximize the time the airship can spend in the air, and at maximum altitude, the problem of deploying the airship over the task force and keep it flying needs a solution.

As air-tanker, the Airship has no chances, as it is way too slow to enable fast jets to refuel from it.

As a COD platform, with a 20 ton crane capable to lower standard TEU containers on the deck of CVF, and with the capability to carry 50 tons or 200 passengers, the airship is quite unmatched.

But the only way I can see an airship used in the Royal Navy is as an additional capability, not as a Crowsnest solution. A small number of airships, fitted with a payload of sensors and surveillance cameras and with a remaining significant payload margin for transport and COD missions would certainly be useful.

But would they be useful enough to justify their cost in a crowded and always tight budget?

The airship might not be the right solution for the present.

It might, however, be the solution for the future, paradoxically. Enter the Lockheed Martin’s ISIS (Integrated Sensor Is Structure) airship, a gigantic high altitude platform meant to fly at 70.000 feet for up to 10 years per sortie, while carrying a massive integral air search radar capable to detect air targets at a range of 373 naval miles in all directions, while simultaneously carrying a monstrous ground surveillance radar system capable to track multiple static and moving surface targets out to 186 naval miles. The airship would be able to relocate globally in a 10 days time thanks to a sustained speed of at least 60 knots and sprints to 100 knots, and operate without in-theatre support. The control element would be CONUS-based (CONtinental United States).  

This capability would replace at once the E3D Sentry AWACS, the Sentinel R1 and the carrier-borne AEW platforms, offering much increased performances over all of them. The US has been working on the ISIS for years, with the LM contract awarded in 2009. A demonstrator might fly next year.

This airship program, if successful, would no doubt represent a true revolution.  

Isis from Stephen Trimble