Sunday, May 29, 2016

S-3 Viking Gunship

We’ve seen that the Marines are trying to create a poor man’s gunship out of their KC-130J Super Hercules tankers using the Harvest Hawk add-on kit.  The Marines are also toying around with turning the MV-22 into a mini-gunship.  So, can the Navy get in on this?  Maybe an E-2C/D Hawkeye gunship?  That probably wouldn’t be any sillier than what the Marines are doing but, just for fun, let’s take a look at a study that was done many years ago about turning an S-3 Viking into a gunship.  Taylor Emanuel did the study for his Naval Posgraduate School thesis (1).

To begin with, the author notes that organic fire support capability was being steadily reduced. 

“This study provides analysis that shows a huge reduction in expeditionary fire support capability. The Marine Corps has experienced a 45 percent reduction in cannon artillery, the loss of self-propelled artillery capability, and reductions in tactical aircraft. The Navy has decommissioned all battleship NSFS 16-inch gun platforms and mine threats coupled with limited littoral water depths will probably make NSFS 5-inch guns a non-factor.”

So, even back in the early 1990’s the trend of steadily shrinking fire support was obvious and this trend provides the foundation and justification for his examination of gunship options.  Interesting, isn’t it, that the author saw the inadequacy of the 5” gun for fire support long before the Navy opted to retreat to 25-50 miles offshore?  Those artillery reductions have only gotten worse and have been joined, now, by tank reductions.  The organic fire support situation has only gotten worse - far worse.

The author’s solution is to increase Close Air Support (CAS).

“To offset reductions in organic fire support, more frequent and sustained application of CAS and CAS/TIC [TIC = Troops in Contact]  will be required by joint expeditionary forces.”

He uses four measures of CAS to determine merit:

  • target detection/recognition
  • lethality
  • survivability;
  • combat persistence.

That’s not a bad group of measures for CAS.  Of course, just as important, or more so, is the direction of the battle – the ability of the pilot (or observer) to see, assess, and direct the battle.  However, that’s a function of training and doctrine and the author is focused on the platform so he can be forgiven this omission. 

Here is the author’s summary of desired characteristics.

“The sensor suite consists of a turret mounted forward looking infrared and low-light-level television to provide 360 degree battlefield coverage and to cover the entire electromagnetic spectrum. The weapons suite consists of one 25-MM Bushmaster chain gun for area suppression of personnel and use against light armor, one 30-MM Bushmaster II gun for destruction of vehicles and armored vehicles, and eight Hellfire missiles for hard-target kill and forward-firing, non-orbit firing capability. In addition, the platform will be survivable. It will have state-of-the-art self-defense capability coupled with armor plating and redundant systems. Finally, combat persistence will be good. The CBG [carrier based gunship] will be carrier-capable and have at least a 1,500 nautical mile range.”

The platforms that the author examines for CAS suitability are the E-2C, S-3, and V-22.  The specific relevant characteristics of the S-3 Viking in the gunship role are:

  • High wing – minimize interference with weaponry
  • Good range/endurance
  • High speed
  • Cabin height over 7 ft – allows full installation and operation of weapons
  • Crew of 4 – would result in task saturation according to the author;  four is the minimum viable CAS crew size, according to the author
  • Comprehensive sensor suite – FLIR and ISAR already part of the airframe
  • High IR signature – means the aircraft would be susceptible to heat seeking weapons
  • Low Radar signature – low on a relative basis, not compared to full stealth aircraft
  • Good munitions load capacity
  • Full weapons load
    • 1x 25mm
    • 2x 30mm
    • 8x Hellfire


As the author points out, the Navy, and carrier groups, lack any real close air support.  As ComNavOps has pointed out, in a peer level assault the carrier's aircraft will be fully occupied trying to establish and maintain air control and protecting the carrier/amphib groups.  They will only sporadically be available for CAS, at best.  

The author’s thesis demonstrated that the S-3 offers the possibility of a dedicated CAS platform though it would not, of course, be as effective as a purpose designed, new aircraft.  Still it’s an interesting concept to think about and once again emphasizes the versatility of the S-3 which has operated in the ASW, ISR, maritime strike, ESM, tanker, and COD roles.  That’s a pretty impressive and versatile aircraft!


(1)Taylor C. Emanuel, “Gunship Diplomacy: Carrier-Based Close Air Support For Joint Expeditionary Forces”, Naval Postgraduate School Thesis, Dec 1994


  1. AWESOME ARTICLE! i think you forgot about its weapons bays though! this plane could also carry a few SDB's internally!

    1. Yeah, I wondered about that. The author didn't provide any schematics or detailed descriptions of how the sensors and weapons would fit. I don't know if they would take up bay space or not.

    2. CNO,

      I love gunships, but I think that the "gunship concept" is long in the tooth - even in COIN.

      The key provision of the gunship was:

      1. Low cost air-frame: look at what new gunships cost!

      2. High accuracy from side firing weapons - low cost PGMs are at least viable alternatives (and in many cases superior. A guided 120mm air dropped mortar can do a lot of damage compared to a cannon. Guided rockets (5" and 70 mm are the cat's meow).

      3. Side firing weapons used to call for unpressurized cabin, which conflicts with 20,000'+ altitude requirements. People who think an AC-130 is anything like as fast or long-legged as a C-130 are ignorant - those guns hanging in the slip stream are literally a huge drag on performance.

      4. Gunship tactics revolve around pylon turns (circular orbit) and that makes air attacks predictable.

      5. The real weapon of a COIN aircraft are a radio in the hands of aircrew who know how to tactically employ TACAIR/artillery and who understand the situation on the ground.

      Looking through the history books, the most effective ground attack aircraft (ironically re-categorized as a bomber) was the Douglas B-26 Invader and that even in the heyday of the gunship.


    3. On the B-26 I was referring to the Vietnam era B-26K vs AC-119/123/130.

      A WWII B-26 could out turn an ME-109 after it dropped its ordinance and a few fighter pilots were hunted down by these amazing aircraft.


    4. GAB, please don't mistake this discussion for my supporting gunships in general. I've stated in other comments that I do not believe they're viable in high end combat. I do, however, like them for low end combat under the right circumstances (they should be programmed directly into operations as a supporting element rather than called sporadically called on, on an as-needed basis.

      The premise of this discussion is the Marine's desire to convert their KC-130's into poor man's gunships. If the Marines are determined to have a gunship, I've offered the S-3 as an alternative that doesn't require pulling scarce and valuable KC-130's from their primary missions and risking them for small gains. Better to use an aircraft that no one wants, anyway. Also, the S-3 is carrier capable which is an important point for the kind of expeditionary role the Marines see for themselves.

    5. CNO got it!

      Gunships still work well for SOF (SOCCOM pays for the modifications), but I think the conventional force needs to look at a different concept.


  2. Interesting concept but probably undoable. From what I've heard the South Koreans are buying the best 20 or so air frames stored at the Boneyard. The remaining ones are basically junk.

    1. It's only undoable if we want it to be undoable. We can rewing, respar, re-engine, re-fuselage, re-anything if we want to. Look at the B-52 or the current Hornets that are, essentially, being rebuilt to extend their service lives.

      Heck, the stripped down condition of the S-3's in storage would actually mean it's cheaper to repurpose them because the stripping down part is already done!

      This post was an odd mix of a bit of tongue-in-cheek sarcasm, mocking the Marine's attempts to turn everything into a gunship, a bit of homage paid to a versatile S-3, and a bit of "why not?" since it's at least a better idea than many of the silly ideas that are actually being acted on. At least converting an S-3 wouldn't take vital and scarce aircraft away from their existing missions!

      That SKorean rumor has been out there for some time and I have yet to hear of any contract or actual commitment from either the US or Korea. Let me know if you hear of anything official.

    2. While Harvest Hawk is not a dedicated system like the AC-130, it offers a CAS capability the Marines need. Eventually, Harvest Hawk will carry 4 Hellfires or 16 laser-guided 70mm rockets, a Mk 44 30mm cannon, and 10 Griffin or Viper Strike precision guided munitions, plus the associated fire control and sensors. The ASFOC rejected the Mk 44 as it lacked the accuracy for their needs, but the Marines think it could work for them. And, Harvest Hawk has been used in combat.

      On the other hand, the Navy needs to its CAS capability too. I like the idea of bringing back the S-3 for a variety of reasons. But for the CAS role, I would bring back a modernized OV-10, especially since it can be flown off the LHD/LHA class of ships.

    3. Harvest Hawk is a gimmick promoted by manufacturers for obvious reasons and by the Marines to ensure more V-22 budget. If the Marines really think they need a gunship then they can simply buy a true AC-130 Spectre for far less than they'll wind up spending on this poor man's gunship.

    4. eh? A C-130J costs ~70 million. A Harvest Hawk kit is a bit over 2 million. Its a pretty cheap system cost wise and a whole hell of a lot cheaper than a C-130J dedicated let alone an AC-130J.

    5. I'm talking about the overall spending on an on-going, never ending program. The Harvest Hawk program already has several iterations proposed. The Marines will spend umpteen millions of dollars on the development and testing of the entire program, if they opt to go that route and they'll still only wind up with a poor man's version of a gunship. Look at what the Navy is going to spend to make the V-22 into a tanker - and that's an aircraft that already has almost all the requisite capabilities and equipment!

    6. ROK Viking sale Sea pretty certain.

    7. I wouldn't dismiss Harvest Hawk so easily. Yes, without the right leadership, it could become a science fair project. But, I don't that happening.

      France has shown an interest in Harvest Hawk and given about 100 Super Hercules are operated by other countries, I suspect other countries will take a look at it too.

    8. Walter, you're missing the big picture. The Marine's KC-130's have a mission and, according to the Marines, there are not enough aircraft for the mission. It's not like we have extra aircraft sitting around with nothing to do so why not put them to work. Every aircraft diverted to this poor man's gunship will be one that isn't performing its main task(s).

      Do you know any developmental project in the last couple of decades that hasn't turned into an acquisition nightmare of runaway costs and schedule delays? I'll say it again, if the Marines really want a gunship, buy a Spectre and be done with it. It's a known price. No developmental costs. Over and done.

      Look what the Marines have done with a simple AAV upgrade. Yikes!!! Two decades, a gazillion dollars, and nothing to show for it. Harvest Hawk will be more of the same.

      Do we really want to risk vital aircraft playing baby gunship?

    9. atsMay 29, 2016 at 5:03 PM

      eh? A C-130J costs ~70 million. A Harvest Hawk kit is a bit over 2 million. Its a pretty cheap system cost wise and a whole hell of a lot cheaper than a C-130J dedicated let alone an AC-130J.

      That $2M kit is nothing compared to the training and O&M costs associated with maintaining the capability!

      Think this through, now these aircrews need NVG rating (and associated flight hours). They also will require flight hours for dropping ordinance. You will have to add additional armorers, EOD, and ground crew to handle ordinance.

      By way of example, adding a refueling probe to a Army MH-60 ($ 5Million per aircraft in 1997 dollars), ended up imposing a $1 million dollar per year training cost! I forget what the impact was on numbers of soldiers, but it added one civilian contractor rep per aircraft, required the Army to pursue additional aircrew training, survival equipment (HEEDS bottles), additional tools and ground support equipment. Big costs for flight hours for overwater flights, deck landing qualifications, and of course the aerial refueling training flight hours. But the unreported costs were that it imposed additional training requirements on the USN (ships for DLQs), USAF/USMC for aerial tanker support and so on. Impact on PERSTEMPO and other training requirements is likewise different to estimate.


  3. SC-3
    1x 25mm
    2x 30mm
    8x Hellfire

    4x 7.62mm miniguns
    4x 20mm miniguns

    2x 20mm
    1x 40mm
    1x 105mm

    I think you've fallen for the "that sounds cool" trap you frequently berate me for :)

    The cannons might offer some suppressive fire, but thats not really the point

    The USMC, and west in general, has lost huge amounts of organic firepower, the author notes, gone are the 16" guns and gone are 45% of the artillery.
    400mm, 155mm and 105mm guns cant be replaced by 25mm cannons.

    1. You may have misread the post. Nowhere in the post did I suggest that the military should abandon the AC-130 Spectre and, instead, buy Viking gunships! The post was a combination of a bit of mocking of Marine air, homage to a versatile Navy aircraft that I'm fond of, and just the enjoyment of reading about an interesting concept. I'm not suggesting that the Navy immediately go out and start making Viking gunships - on the other hand, there are a lot dumber ideas being acted on!

  4. Presumably you could operate HIMARS from a deck and there are still the Cobras. Is it possible to re-fit the 155mm used on Zumwalt or incorporate into new builds of Arleigh Burkes?

    That said, imagine the cool new shell types you could fit into a 16" now. Extended range, guided munitions, 406mm gives you lots of options. Maybe a 16" railgun?

    1. The Zumwalt was, literally, designed around the 155 mm gun. The ship is the size it is largely due to the gun system. The gun cannot be adapted to a Burke. Plus, the gun is of limited use. It can fire only one type of munition and that munition is hideously expensive.

    2. CNO, the AGS was adapted to the Burke platform almost immediately after BAE finished the initial part of the AGS' design work.

      That's what the 'AGS-L' is.

      That being said, the Navy rejected this design and for good reason.
      The AGS shell types are limited (as you noted), the ASG-L has an even smaller selection, and the performance of the gun is much less than the full sized version - not to mention the magazine is pathetically small.

      In that sense, if you were meaning that the AGS-L is a failure for the role, then I agree and have no contest.

      - - - -

      "That said, imagine the cool new shell types you could fit into a 16" now. Extended range, guided munitions, 406mm gives you lots of options. Maybe a 16" railgun?"

      You don't have to, just evolve the shell types that were on the Iowa (which was serving as a test bed platform) in the 80s.

      ERGM, SPGP, Cluster Bomb Shells, ASW Shells, Shells that dropped torpedoes (effectively a short ranged ASROC in Shell form), Anti-Sat shells, Anti-Ballistic Missile shells - you name it, they probably were trying to make it happen (and from what I've read, most of them try tried were successes, but they hadn't gotten to all of them yet when the Turret #2 incident happened).

      They had designs to make the Iowas into the world's only truly 'do everything' warship; honestly, with modern technology, I fear what they could come up with.
      Probably the largest reason why I support a return to the 16in guns, they can basically passably perform most functions with already existing technology and could be ready in as little as 1 year 6 months (time to reactivate and fully modernize an Iowa) to 3 years (estimated time to rebuild the industry and forego the old hulls).

      That being said, 11" is the largest Railgun that I've heard of being feasible and you basically need a pair of nuclear reactors to power just one.
      Not a very efficient use of hull space, even on a large ship like would be needed to carry such a gun.

      - Ray D.

    3. AGS-lite has had no development. It is merely a theoretical powerpoint presented by BAE.

    4. Anonymous, AFAIK, the existence of several mock ups and numerous design schematics - many of which are seen in their various publications on the AGS topic - would seem to dispute your claim.
      IIRC, BAE has been trying to no avail to sell the system to various navies as of late, it would take more than 'merely a theoretical powerpoint presented by BAE' to be at that stage.

      The AGS-L is in 'late' development stages and would take little to no further development time to produce.
      The reason why it's not being produced is because it's next to useless in real naval situations, even more so than the full AGS, not that it has 'had no development'.

      - Ray D.

    5. Ray, I'm unaware of any prototype AGS-L. The most recent notable effort was a May 2012 PDF from BAE that described the system. It contained no mention of any physical development having occurred. Let me know if you're aware of any additional work having been done.

      As far as the system having to be more than theoretical, you know that's not a correct assumption. The F-35, LCS, and many other programs were started based strictly on theoretical studies. Of course, most of them have fared poorly, as a result.

      AGS-L is not in late development - it's in paper studies only. That's not late development. Late development is having a prototype and having exercised it.

      As I said, let me know if you have additional information.

  5. An A-10 successor seems to be by far the most prudent choice here. It is a huge mistake to retire that airplane unless a worthy successor (no the F-35 doesn't count) is procured.

    1. The thesis author's scenario and contention was that air bases would not be readily available, especially early in campaigns. Thus, a carrier based gunship would be needed. He was not, at all, arguing for replacing the A-10.

    2. I believe that a carrier based CAS fighter would do far better than a gunship. The problem with a gunship is that it may not be agile enough to dodge medium calibre AA amd IR missiles.

    3. Please don't fall prey to that one versus one comparison logic. If we took your logic to its extreme, we wouldn't have any aircraft except the most super nimble aircraft possible because none of the rest could dodge AAA and IR missiles.

    4. I'm thinking that something like a gunship might not be survivable at all against a modern armed enemy to be honest.

      So far, attack helicopters have not done so well either - and that was in Iraq against a subpar enemy.

      I actually think that aircraft are going to have to be either:
      1. Agile and survivable (the A-10 is survivable, but falls short somewhat on the agility part)


      2. Fast enough and flying high enough that this is not a serious concern.

      That is for combat aircraft of course. Transport aircraft will inevitably be more vulnerable.

  6. The reduction in volume of fire appears to stem from the "second offset" strategy. The military decided to pursue precision guidance in order to increase the lethality per plane. As a result, we needed less planes and firepower capacity in order to achieve the same target destruction - saving money. In order to substitute for naval gunfire, the presence of planes with pgm's must provide suppression. The development of rail guns would likely cause us to reconsider this approach because we could achieve a high volume of fire from over 100 miles from shore.

    That being said, I am thinking about situations in which carrier based CAS would be cost effective or strategically valuable. I suppose we are looking for places where we need CAS but have no airbases or where enemy missile/aerial attacks are likely to disable our few airbases. Does that remind you of anywhere? When would we need carrier based CAS?

    1. A very nice comment and you indirectly touch on so many worthy topics. I don't know where to begin to reply!

      Your observation about the second offset and its relationship to our current numbers crunch could make an entire post. The flaw in the greater accuracy=lower numbers theory is that it fails to account for either attrition or presence. Presence is obvious - a given platform can only be in one place at a time. Attrition is a constant in warfare (though it's a lesson we seem to have forgotten!) and numbers are the only counter.

      Rail guns! Next to useless. I'll have to do a post on that sometime.

      Carrier based CAS. As you allude, the entire Pacific region, meaning China, is short on air bases and long on distance. Of course, Korea, Iran, and Russia all could have scenarios in which our access to bases is denied either politically or militarily and carrier based CAS would be necessary.

      Naval gunfire versus precision air-delivered munitions? There's another entire topic!

      This is just a comment so I'll have to let it go at that. This is one of the more provocative (in the sense of producing strong and interesting reactions) comments I've read in a while. Thanks!

    2. I would add Africa to the list.

      On rail guns, I can see them being useful for hitting a time sensitive target with a few rounds. I doubt they have the accuracy for the CAS role.

  7. Well, good idea, poor choice of airframe. The S-3, or more likely a US-3 does not real carry enough munitions to provide the high endurance require for gunships, nor does it have enough room for the sensor and targeting systems gunships like the various type of AC-130 use.

    I would suggest two other airframe as candidates for the carrier base gunship roll. The first is our good workhorse, the C-2. With their larger playload, and cargo deck they carry more of the equipment need for a gunship.

    The second would be the replacement for the CODs now desired by the Navy. (no not the V-22 version, the one to replace the remaining C-2.) Thee aircraft should carry more than the C-2s, in both weight and size. And by adding the Gunship roll to mission list, along with tanker, transport, drone control and electrons aircraft, (not to mention future E-2 replacement) we can greatly increase the number of airframe purchase resulting in a good price reduction and possible even more competitors for the business.

    1. Yes the NPGS author only briefly looks at the possible S-3 gunship capacity, and doesnt look into weapon weights and field of fire at all. It only seems marginally more capable than a AH1Z viper helicopter gunship, if at all.
      The real reason why is the marines can create an expeditionary airfield close to the shore where necessary and base their Hercules or other gunships there.
      Th days of gunfire over the beach seem well gone, from both necessity because of loss of available barrels and poor results for effort needed.
      Israels Rafael has its NLOS Spike which has range of 16km in its latest version. Unusually its something the UK bought secretly. Based on anti-tank LOS technology it gives long range punch and you can see what you are hitting if fired from a ship.

    2. GLof, you might want to check out the referenced thesis. The author contradicts your points about the S-3 and also evaluates the V-22 and E-2.

    3. Also current STOM (ship to objective maneuver) and sea-basing strategies both are counter to establishing beachheads or fixed bases like expeditionary airfields.

    4. @G Lof, Ztev,

      1. The NPS thesis was written by an AFSOC guy who knew his business.

      2. Most of the WWII PTO campaigns involved seizing islands for airfields - non of them obviated the need for seaborne artillery or air-power!

      3. Time! I do not know why people have the idea that the enemy is going to passively wait for us to knock down coconut trees to build a FARP or setup our logistics systems and what not. This is akin to people dismissing the value of LSTs; the is a huge value in delivering a MBT company in fighting order immediately into the fight and waiting hours for the piecemeal ship to shore delivery of tanks and other AFVs.


    5. "Also current STOM (ship to objective maneuver) and sea-basing strategies both are counter to establishing beachheads or fixed bases like expeditionary airfields."

      I've already debunked the fantasy of Operational Maneuver From The Sea.

  8. This topic was discussed in a 2010 article in the USMC gazette. Google it.

    There are over 70 S-3b aircraft at amarg. All are usable and have another structural service life left in them and could be recapitalized with depot maintenance.
    Re FMS for the ROKN, any USG reuse would have priority.
    Like I said above an article has already been written on this. Check it out.

    1. b2, I can't find any reference to such an article through a general Google search or checking the archives of the Gazette. Do you have a specific link or reference beyond "Google it"?

    2. Author's name is SGT John Raisbek.
      Will try to get a link.

    3. While the idea is interesting, I'd rather see those S3's put to use tanking and doing ASW. I'm still not sure why the Navy took them off that role.

    4. Ostensibly to save money. But it was a horribly short-sighted decision.

  9. If you search that name and add "gazette" the link pops up. Can't figure out how to paste it.

    1. I see an article on close air support by that author that could be it but it's behind a members only wall. I'm signed up for too many things already. I don't want to add another for one article. Oh well. Thanks anyway!

  10. Well, that article was written during the IR surge and came out a year late unfortunately. Goes beyond your1994 article with more facts. I know.
    Trust me, if it ain't v-22 or f-35b the marines don't want hear about it.
    As a vet of the viking variety for nearly 40 years I can tell you there is no one out there with any imagination to reuse it. It would make them look bad.

    1. Have you considered writing an article for Proceedings or some such publication, as a counter to the Harvest Hawk? You might give it some thought.

    2. Cannot. Too close. I am considered a gadfly.
      The reuse at vx30, isr surge wLantirn, tanker redux to help mitigate Hornet dilemma were part of efforts.
      Need the job. Too much anti-Viking sentiment out there.
      Send me your email and I will send you a PDF.

    3. I am unsure about the survivability of a modern Viking (as I've said above) for CAS (which requires taking very heavy fire from the shore), but I think it's still worth considering.

      I have believed that the decision to retire the S-3 without a worthy successor was a terrible mistake.

      An F-18 or F-35 cannot possible operate as well in the ASW role for example.

    4. "I am unsure about the survivability of a modern Viking (as I've said above) for CAS "

      It all depends on the level of the threat. Gunships, including the Spectre, are only deployed when the threat level is low. The same would hold for a Viking gunship.

      I'm not at all sure that gunships are viable over a contested battlefield. Until the threat level is lowered, other methods would be used. (Fast attack jets, attack helos, NAVAL GUNFIRE - if we had it, etc.).

      The most valuable option is naval gunfire. It's all weather, always available, immune to AAW, immune to ECM, and, on a practical basis, is inexhaustible. Unwisely, the Navy and Marines allowed naval gunfire to vanish.

    5. I still think it would be best if we could do CAS in permissive environments from an aircraft that could launch from a 'phib.

      The America class is about the length of an Essex class. And they could launch and recover aircraft with a big enough load to make a difference.

      That would, however, mean adding arresting gear, and making a new aircraft. So I realize that's untenable.

      Alternately, a navalized Tucano might help.

      I'd still bring back the S3's, but as tankers and ASW.

  11. MC gazette 2010 article described above, without notes/etc. :

    FEBRUARY 2010:

    Close Air Support
    Closing the gap in persistent coverage

    by Sgt John G. Raisbeck
    >Sgt Raisbeck is a topographic analyst assigned to 1st Topographic Platoon, Production and Analysis Company, 1st Intelligence Battalion. His educational background includes a bachelor's and master's degree in mechanical engineering.

    The cities of Iraq and the mountains of Afghanistan have and will continue to test our ability to provide fire support. Both environments offer abundant cover and concealment and an enemy that is often close to noncombatants, friendly forces, and sensitive infrastructure. Fire support under these circumstances comes with great risk of fratricide and collateral damage. The Urban and Complex Terrain Close Air Support (CAS) Industry Panel was formed to examine this problem, make recommendations, and provide estimates of time and cost to field a solution. The panel covered all elements of the CAS system: targeting; weapons; launcher; command, control, and communications; and platform. The desirable platform attributes were determined to be persistence, availability, firepower, survivability, stealth (visual and aural), connectivity, and targeting. Four aircraft were selected as surpassing the point of departure for a near-term solution: A-10, AC-130, C-130, and MQ-9.1 However, the panel overlooked an aircraft that potentially possesses all of the requirements, the S-3 Viking.

    The S-3 Viking entered service with the U.S. Navy as an antisubmarine warfare (ASW) aircraft in 1974. It is a subsonic, all-weather, carrier-based aircraft of conventional design with twin turbofan engines mounted under high-mounted wings. Its TF34 turbofan engines are the same ones used by the A-10 Thunderbolt. Additionally, it is similar in weight and payload capacity to the A-10. While lacking the survivability features and cannon of the other aircraft, it has far greater range, 3,368 nautical miles (nm) ferry range with two 300-gallon external tanks2 versus 2,240nm with three 600-gallon external tanks.3 In the late 1990s the ASW equipment and personnel were removed and a new emphasis was placed on surface warfare. The space and electrical power required for the ASW mission makes the airframe suitable for other types of missions. Variants designed for electronic intelligence (ES-3A), aerial refueling (KS-3A), and carrier onboard delivery (US-3A) have been developed. Despite its utility the S-3 Viking was retired by the Navy. The last squadron was decommissioned early last year. Only four aircraft have been retained by the Navy to patrol the Pacific Missile Range.

    The S-3's suitability for CAS is organized below by the attributes that were selected by the CAS panel: availability, survivability, persistence, firepower, connectivity, targeting, and stealth.

    Availability. While only 4 are still in active service with the Navy, over 70 S-3Bs are in the early stages of processing at the Aerospace Maintenance and Regeneration Group (AMARG), including 30 in Section 3 for highly preserved in foreign military sales reserve spared at 100 percent.4 Therefore, they can readily be returned to service.

    In spite of its age, the S-3 fleet has many years of life left in its airframes. Full-scale fatigue tests concluded in 2004 by Lockheed Martin indicated that the airframe could last for up to 23,000 flight hours. The fleet's average number of flight hours is less than 13,000.5 Its longevity is further enhanced by its engines still being in production for the A-10.

  12. Part2-
    Survivability. Since the S-3 has a service ceiling of about 40,000 feet,6 it can operate outside the range of man-portable air defense systems (ManPADS) and small arms fire (SAF). Additionally, like most manned military aircraft, it possesses electronic support measures and countermeasures dispensers for when it must fly in the threat envelope. Finally, while not designed to withstand battle damage, the aircraft has dual hydraulic actuators, manual reversion, and twin engines that are separated by the fuselage. Therefore, it should be able to survive a single ManPADS hit or some SAF. If survivability systems are deemed necessary, retrofits, such as self-sealing coatings, explosion suppressing foams for fuel tanks, and ballistic armor for cockpits, are available.

    Persistence. Either high endurance, forward basing, or aerial refueling can achieve persistence. With external tanks the S-3 can stay aloft for 7 to 8 hours7 and is capable of in-flight refueling. The S-3's high endurance gives it the advantage of providing persistent support in circumstances where forward bases and tankers are not available.

    Firepower. While having a payload capacity of nearly one-half of its weight,8 the S-3's weapons payload is hampered by relatively few hard points. It has four hard points in its bomb bay and one hard point on each wing. The dimensions of the bomb bays limit the internal hard points to weapons the size of an MK46 torpedo or smaller, such as the MK82-based joint direct attack munition, Guided Bomb Unit 38. The external ones have carried stores up to a nearly 3,000-pound aerial refueling pod and are rated for Harpoon, Maverick, and SLAM-ER (standoff land attack missile expanded response) missiles.

    Programmable global positioning system-guided munitions require a Mil-Std-1760 (Military Standard 1760) interface. At least 20 of the S-3s at AMARG in Section 3 have that interface on the external hard points, and all of the Section 3 aircraft have the Mil-Std-1553 data bus that is the basis of Mil-Std-1760.9 Installing 1760 interfaces in the bomb bays and using 1760-equipped multiple ejector racks on the external hard points, such as the Digital Improved Triple Ejector Rack BRU-42 (Bomb Release Unit 42) and BRU-55, would greatly increase the quantity of precision guided munitions (PGMs) that could be carried.

    Finally, the S-3 has what is effectively a second bomb bay that is currently unused, its 60 sonobuoy chutes located aft of its bomb bays that can carry 2,150 pounds of sonobuoys.10 While traditional air-to-ground ordnance would not fit in this space, an emerging class of weapon will fit, the small (50 pounds or less) PGM. Small PGMs were the CAS panel's solution to targets in populated areas and danger close to friendly forces. Several are in development, but the GBU-44 Viper Strike is the only one that has received an official designation. A platform independent launcher, called the common launch tube (CLT), has been developed for this new family of weapons. The CLT is identical in operation and similar in size to the sonobuoy tubes used by the S-3. After consulting Systima Technologies (the developer of the CLT) and PMA-290 (the Naval aviation program that supports the S-3) about replacing the chutes with ones that can hold CLTs, they concluded that it is feasible. However, the number of CLTs that can be installed and the cost cannot be estimated without official interest. Weaponizing the sonobuoy chutes would increase the total weapons payload capacity, enable carriage of small PGMs without using one of the few hard points, and in conjunction with the bomb bays offer a diverse, aerodynamically clean weapons load out.

  13. Part3
    Connectivity and targeting. Currently, the S-3's optics are limited to infrared, and its radar is not suited for operations over land. It has performed intelligence, surveillance, and reconnaissance (ISR) missions in that environment with the aid of LANTIRN and LANTIRN-ER pods in conjunction with the video transmission system that was removed from decommissioned F-14Ds.11 However, a targeting pod occupies one of its only two external hard points. Replacing the retractable forward-looking infrared turret with a multispectral targeting system would free the hard point and allow the aircraft to exploit the 360-degree attack capability of recent PGMs. Additionally, a high resolution synthetic aperture radar (SAR) with ground moving target indicator that is capable of mapping terrain and tracking ground targets can replace its inverse SAR.

    These improvements are not speculative. They were part of the surveillance system upgrade (SSU) that was demonstrated but not implemented from 1999 to 2003.12 Other features of the SSU include Joint Tactical Information Distribution System Link-16, demand assigned multiple access satellite communications, tactical common data link, and the Over-the-Horizon Airborne Sensor Information System III that integrates all of these data feeds into a single operational picture.

    Stealth. Other than its paint scheme, the S-3 has no features intended to reduce the ability of human observers to detect it. However, its lower flight speed relative to strike fighters, 350 knots cruise and 165 knots loiter,13 results in less aerodynamic noise.

    Other attributes. The following attributes were not specified by the CAS panel, but are beneficial to the CAS mission:
    Carrier capability: as a carrier aircraft it is inherently expeditionary.

    Tanker capability: with a "buddy pod" the S-3 can serve as a tanker, a role that it performed for many years in the fleet. Therefore, an S-3 can receive tanker support from its own squadron.

    Extra crew capacity: with the removal of the ASW personnel two of the S-3's four seats are vacant. Thus, it can easily accommodate a forward air controller or a tactical air coordinator.

    Low speed loiter: it can loiter at 165 to 180 knots, enabling it to stay close to ground forces.

    Smaller logistics footprint: when operating ashore, the S-3's fuel economy can help reduce the number of convoys that could need CAS.

    Many of the above features also belong to the Navy's other fixed-wing ASW aircraft, the P-3. While not designed for carrier operations, it has greater range and payload, is still in service, and already flies ISR missions over Iraq and Afghanistan. So why not use it for CAS? What the P-3 does not have is time. The P-3 airframes are reaching the end of their life. The Navy has currently grounded 39 for wing replacement, and another 6 to 10 groundings for wing replacement or modification per year are planned.14 Nonetheless, the P-3 must continue to operate beyond 2013 when its replacement, the P-8 Poseidon, is scheduled to enter service. Therefore, adding CAS missions to its workload is not advisable.

    The purpose of this article is not to merely point out an oversight of the CAS panel. Its purpose is to argue for the return of the S-3 to active service as an ISR/CAS platform. However, the above reasons are not enough without considering the other four aircraft selected by the panel.

  14. Part4
    The S-3's range is less than that of the much larger C-130, 4,250nm for a C-130H with maximum fuel including external tanks and 15,611-pound payload,15 and close to the unmanned MQ-9's range of 3,200nm.16 It can loiter near the cruising speed of the slowest of these aircraft, the MQ-9 at 200 knots,17 yet it has the highest maximum speed of this group, 450 knots at 20,000 feet.18 Size and weapons payload are closest to those of the A-10. Availability falls between the hundreds of both A-10s and C-130s and the scarce AC-130s (25)19 and MQ-9s (35).20 However, the C-130's availability for CAS is restricted by armament kits, such as the Marine Corps' Harvest Hawk, that are still in development. Finally, while the S-3 is unsuited for rough airfields due to its engine placement, it is the only one of these aircraft designed to operate from an aircraft carrier. In conclusion, the S-3 is a unique asset. Nothing else can practically take off from a carrier deck and deliver as much firepower, as far, and for as long without support as the S-3. This is particularly important in Afghanistan where terrain and elevation can preclude the use of forward airstrips and rotary-wing assets.

    Neither upgrading sensors nor modifying airframes are trivial matters. Nonetheless, those efforts are minor compared to the cost of a new aircraft and cost-effective given that an upgraded S-3 would have more flight hours left than a new Super Hornet (6,000 hours designed minimum that may reach 9,000 hours).21 Furthermore, not all of the improvements above are necessary, and they can be implemented incrementally to reduce risk. For example, merely installing Mil-Std-1760 interfaces in the bomb bays of a LANTIRN-equipped S-3 would permit it to provide persistent CAS with up to five PGMs; small PGM capability could be added using a CLT pod on the external hard point opposite the LANTIRN pod.

    Why present this proposal in a Marine forum? Due to the Corps' relationship with the Navy, it has a vested interest in the Navy's capabilities. Both naval and Marine aviation currently have a capability gap in the area of long-range, high-endurance CAS platforms. Harvest Hawk will provide some help, but the need to retain the KC-130J's primary role will limit its firepower to a supplementary level. The Navy has two aircraft that could serve in this role, the P-3 that is trying to satisfy the demand for ISR and remain airworthy and the S-3 that has been retired. Without external influence the Navy is not likely to reverse its decision to sundown the S-3. The Navy will argue that it cannot afford to keep the S-3 and will probably suggest that any interested Service takes the ones that are in AMARG. The Marine Corps' willingness or ability to acquire the S-3 will not be discussed here. However, regardless of Service, given the scarcity, condition, and desirability of aircraft suitable for CAS in these challenging environments, can we afford to leave the S-3 in the boneyard?

  15. He uses four measures of CAS to determine merit:

    •target detection/recognition
    •combat persistence.
    The author laid this concepts out in a specific order and for a reason.

    Almost every comment ignores "target detection/recognition."

    This was I believe the primary reason the S-3 went to the top of the list in the thesis.

    Amazing how everyone focuses on weapons load and ignores sensors and communications. Logistics is never even mentioned in these discussions!



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