ASW Helicopter Procurement for the Philippine Navy

An AW159 in flight. Photo courtesy of Cpl Kellie Williams, RLC/MOD thru Wikipedia Commons.
An AW159 in flight. Photo courtesy of Cpl Kellie Williams, RLC/MOD thru Wikipedia Commons.

The Department of National Defense (DND) recently announced the allocation of P5.4 Billion (USD 120 million using the Exchange Rate of USD 1 = P 45) for 2 brand-new Anti Submarine Warfare (ASW) Helicopters for the Philippine Navy (PhN), and they expect the acquisition process for these helicopters to be completed within the year.[1] The news item says that the 2 ASW Helicopters will be assigned to the Del Pilar-class ships, but I am not sure about the accuracy of this as we do have 2 brand-new Frigates which will be needing helicopter support also, hence it makes more sense to assign these units to those Frigates. It is possible that if the helicopters arrive first, they will initially be assigned to the Del Pilar-class ships, but will eventually be moved to the new Frigates once those arrive.

The budget of USD 60 million per helicopter came as a bit of a surprise for me mainly because first, I found it a bit high. At that budget, each helicopter will be almost twice the price of the FA-50 Fighting Eagle Advanced Jet Trainer (AJT) we are getting which is valued at only USD 35 million each.[2] Second, it seems that while we are getting top-of-the-line ASW Helicopters, there doesn’t seem to be any effort to get any sonar equipment for the Del Pilar-class ships, while the sonar requirement for the 2 new Frigates are only generally/loosely defined or not very specific.[3]

Because of this, I get the impression that the PhN plans to use these ASW Helicopters as the MAIN ASW tool for either the Del Pilar-class ships or the 2 new Frigates. I could be wrong, of course, but right now this is the impression I am getting, and if that is really the case, then I have some doubts about it.

‘ASW 101’
First off, ASW Operation is a pretty complex affair, hence let me just share this fantastic reference I found on the web about it. I think the people who wrote it should’ve spun it off to a book, I definitely would’ve bought one. It can be used as reference for the terms used in this blog.
ASW Tactics 101 Part 1
ASW Tactics 101 Part 2
ASW Tactics 101 Part 3

‘ASW Helicopter Operation’
Helicopters are very useful in ASW operations because they can be used in a number of ways. First is that they can scout ahead of a ship to look for submarine contacts using equipment such Dipping Sonar (sonar equipment that is lowered from the helicopter into the water via cable) and/or Sonobuoys (disposable, remote sonar equipment dropped into the water).

But the main way an ASW Helicopter is normally used is to CONFIRM suspected submarine contacts. For example, if a sonar-equipped ship detects POSSIBLE submarine contacts around the ship and is able to get its approximate BEARING (direction relative to the ship) and estimated RANGE from the ship, then it can direct the ASW Helicopter to that suspected location. The ASW Helicopter can then confirm the presence of a submarine by using the variety of equipment at its disposal to “triangulate” the location of the sub.

This can be done using a number of ways, like if a Dipping Sonar is used then the sonar is dipped in multiple locations around the suspected submarine area and activating its active sonar. The idea is to get a bearing and range reading from each dip, and then calculating their intersections to determine the submarine’s exact location. Using Sonobuoys will be easier and faster as their will be no need to make multiple passes or dips as each Sonobuoy is already at different locations, but Sonobuoy use are expensive as they are disposable and each one costs at least USD 250.[4]

Alternatively, the helicopter can also use a Magnetic Anomaly Detector (MAD) (detects the variation in the Earth’s magnetic field due to the presence of a submarine’s hull) to confirm a submarine’s location by making a series of parallel and then perpendicular passes to determine a submarine’s location.

‘ASW Helicopter Attack’
Once the ASW Helicopter has the exact location of the enemy sub, if given the permission then it can go and attack it with a Lightweight Torpedo it normally carries. Helicopters are ideal platforms to launch weapons against submarines because they can travel quickly to a location, much faster than a torpedo can. The ASW Helicopter can then drop the torpedo literally almost on top of the submarine, giving it less time to detect and react to the threat and thus increasing the chances of a kill.

Torpedoes when launched from surface ships or submarines are S-L-O-W to arrive to their target, making interceptions of moving targets more complicated. For example, a torpedo traveling at 45 knots or 52 kph will take almost 6 minutes to travel 5 km, upon which time a moving target would’ve gone a certain distance already hence the need to account for that also. This is why it is more ideal to have helicopter drop a torpedo nearer to an enemy sub (either that, or use Rocket-Assisted Torpedoes).

‘ASW Helicopter Limitations’
However, helicopters do have limitations of their own. First is that they have limited endurance of only up to a couple of hours before they need to refuel or even change to a “fresh” crew if needed. Second, all aircraft like helicopters have “consumable” flight hours, hence every time you use them you are eating away at those flight hours, and the faster you use them the faster you will reach the required next maintenance overhaul period.

A Kongsberg ST2400 Variable Depth Sonar (VDS). Photo courtesy of Wikipedia Commons.
A Kongsberg ST2400 Variable Depth Sonar (VDS). Photo courtesy of Wikipedia Commons.

Also, the more a helicopter is used, the more it wears out which could lead to maintenance problems causing downtime as the aircraft is being repaired. Lastly, helicopters can also be lost due to combat attrition (i.e., shot down). Most ships also only carry 1 helicopter at a time, hence if the helicopter is lost due to some reason and the ships rely on it as its main ASW asset, then the ship will be vulnerable to a submarine attack.

‘Ship-Based Sonar Equipment’
Because of this, ASW Helicopters need work in conjunction with ships to ensure that there will be no “gaps” in ASW coverage that a submarine could exploit. In fact, ship-based ASW equipment should be considered as the MAIN tool for ASW, with ASW Helicopters as SECONDARY tool for ASW to COMPLEMENT the ship’s ASW equipment. Ships also can carry better sonar equipment because they are less limited in terms of space, weight or power requirements than a helicopter, hence ship-based sonar equipment can be bigger, heavier and more powerful and thus are generally better than helicopter-based sonar equipment.

Actually for me, it is better to have a ship with advanced sonar equipment paired with a smaller ASW Helicopter rather than have a ship with mediocre or no sonar equipment paired with a large, advanced ASW Helicopter. The former is not ideal because it means less ASW capability overall for the ship-helicopter combination.

One of the best sonar equipment available for ships right now are what’s called a “Variable Depth Sonar” (VDS), basically a towed sonar equipment which can vary its depth also. Towed sonar means that the sensor is located away from the noise of the ship’s engines and propellers, making it more effective at detecting submarines. Another advantage of a VDS is that it can be lowered to the Thermocline Layer where submarines usually hide as it can reflect some of the active sonar signals activated from above the layer. An example of a VDS system is the CAPTAS-4[5] used on the newest FREMM Frigates by France and Italy.

VDS are usually used in conjunction with Bow or Hull Sonars as the VDS do provide some speed and maneuvering limitations when being used, and also time has to be spent when reeling them in or out. Hence in times when you need to travel faster and/or do a lot of maneuvering, you would want to still have some sonar capability with your Bow/Hull sonars to detect submarines and/or (worst) their torpedoes.

‘Torpedo Decoys’
Lastly, despite all of these equipment, my opinion is that current ASW technology tilts slightly in favor of the submarine as shown in the Falklands War on BOTH sides of the opposing forces, hence if the Philippines plans to have a really serious naval deterrent against China, then it has to acquire submarines. I plan to blog more about this later, but in the for now this means that PhN should also invest in TORPEDO DECOYS as it is likely that no matter how good your ASW technology is, advanced Submarines with a well-trained, experienced and determined crews will likely be able to get at least a Torpedo shot off, hence the importance of decoy systems against Torpedoes.

Among these systems would be the AN/SLQ-25 “Nixie”[6] which is a towed decoy that mimics a ship and is designed to draw torpedoes to it. Even though I think current ASW technology favors the submarine, it still pays to have a strong ASW capability to discourage more attacks from submarines. A weak ASW capability only encourages more submarine attacks, increasing the chances of a submarine severely damaging or even sinking the ship.

‘Parting Shot’
These 2 ASW Helicopters were supposed to be paired up with the planned purchase of 2 Maestrale Frigates a couple of years ago,[7] and the ship-helicopter fit THEN would’ve been excellent because despite its age, the Maestrale Frigates are great ASW ships. It could carry 2 helicopters for redundancy, had a Prairie-Masker system that made it harder for submarines to detect it, and it had a VDS system.[8] However, the purchase of the Maestrales were cancelled, but the acquisition of its ASW Helicopters continued.

Getting these expensive ASW Helicopters is actually still very good news, but I think the PhN should also acquire advanced sonar and decoy equipment for its ships to ensure a “proper fit” or “proper pairing” between ship and the advanced helicopters, and right now there are no publicized plans yet to acquire any such equipment.

The PhN has expressed preference for the AW-159 Wildcat for the ASW procurement,[1] and it seems to be a good choice as it is going to be the main ASW Helicopter for the Royal Navy[9], although how it fares with other ASW Helicopters right now in the market remains to be seen. Note that we are getting a lot of helicopters from Agusta-Westland (AW), 5 AW109s for the PhN and another 8 AW109s for the Philippine Air Force, and so far the PhN has been very satisfied with the service provided by AW[10] hence probably the preference for another AW product which is the AW159.

An AN/SLQ-25 Nixie Torpedo Decoy being reeled in. Photo courtesy of Wikipedia Commons.
An AN/SLQ-25 Nixie Torpedo Decoy being reeled in. Photo courtesy of Wikipedia Commons.


^[1] DND earmarks P5.4B for anti-submarine choppers,

^[2] PAF going back to supersonic age with South Korean jets,

^[3] Philippine Navy New Frigate Acquisition Timeline,

^[4] NAVAIR Sonobuoy Team Innovation Earns DoD Recognition,

^[5]CAPTAS-4 Variable Depth Sonar,

^[6] AN/SLQ-25 Nixie,

^[7] Philippine Navy To Buy Two ASW Helicopter,

^[8] Maestrale-class frigate,

^[9] AW-159 Wildcat,

^[10] Navy pleased with support of AW-109 suppliers,

42 thoughts on “ASW Helicopter Procurement for the Philippine Navy”

  1. I think the preference for the wildcat is because of its size. I think the seahawks by the us is larger and might not fit inside the del Pilars so I expect the helo hangers of the new frigates are also not that large. Though the wildcats have asw i think its not enough to ensure the protection of the PN against subs. I would have used the money on equipping the del Pilars with an asw suite or additional budget for the new frigates or purchase stealth missile boats like the Haminas of Finland or a second hand p3 orion sub hunter. In any case it would be a great training platform for our Filipino sub hunters. Other than world war 2 are there any incidents wherein an ASW aircraft downed an actual sub? Falklands? Does the Falklands count if argentina used world war 2 era subs? Just heard in the news Russia just confiscated Ukraines’ sub in Crimea (sayang binigay nalang sana sa atin hehehe).

    1. The only one I know was the Falklands War, when ASW Helicopters heavily damaged the WWII era submarine ARA Santa Fe. The sub was running above the surface when an ASW Heli spotted her on radar, then it was attacked with Depth Charges, Missiles, Machine Guns, etc. It seems the Captain was incompetent as aside from running on the surface instead of at least snorkeling, he didn’t even dive when he was being attacked.

      Personally, I think its almost useless to have an expensive ASW Heli and yet not having at least a VDS system. Hull or Bow sonar only is not good enough, they need VDS or if the US will let us buy them, their towed array systems …

  2. 60 Million dollar each? Wow we will have the most modern ASW helos in South East Asia.Compare it to our neighbour, our heli will be the most expensive thats mean most advance.

    1. Well, in fairness, the other SEA nations bought their ASW Helicopters way before than us. It is likely that when they replace their helicopters in the future, it will be in the class and price range of the AW159 …

  3. well, i can mention one incident not sinking subs but i just forgot the european country involved, it was news several years ago, they were able to track the russian attack sub entering their domain. they used their ASW helos using sonars and the poor sub was not able to get away. only upon negotiations between that country, the U.S. and the russians that the submarine was able to leave unharmed. again, air warfare tactics is till superior against naval ships and submarines. therefore, since we cannot immediately acquire new frigates because these will cost as from a minimum of $250m- to $500m per ship, we just as will be contend with the del pilars, peacocks and our world war 2 relics parolling the west philippine sea, just back up them with helo gun ships capable of carrying anti ship and ASW missiles. i prefer the eurocopter AS565 MB Panther being a medium size it might fit with our del pilar’s but carry the mistral air to air missiles, AS 15 TT anti surface missiles, HOT anti-tank missiles and the MK 46-anti sub missile. and it much more cheaper than the other ASW helos.

  4. on the first look, it would appear to be a major lift for the PH navy. but understanding what you have just written here, it would appear that the 2 helicopters is nothing but a “pasindak” show. but is it really that bad a decision to have those 2 helicopters at this point in time?
    me thinks that it may not be that bad at all economically speaking since those birds would cost way beyond its current price than 2 or 3 years after when the 2 new frigates will be on hand for PH navy.
    but naval strategically speaking, i have more questions especially that am just an ordinary observer. I just hope that those pushing the buttons in the heirarchy have something they know that we don’t normally know.

    1. I am not against the buying of these helicopters per se, I just hope the PhN would ALSO buy good towed sonar equipment for the ships these ASW Helicopters will be assigned to. If they just buy these and not any towed sonar equipment, I admit I would be disappointed.

  5. yes, our ships specially the del pilar (not only proposed upgrade to carry anti ship missiles)must also have towed sonar equipments to compliment the ASW helicopters. the helicopters cannot respond if not detected first by the ships. we could not just always deploy the ASW helos to be used to detect submarines which is very costly just because ours ships dont have sonars.

    1. Hopefully when obama comes here next month they could give us uscg whec mellon. Its the only Hamilton class cutter that was equipped with full sonar-asw suite, harpoon missiles, ciws and torpedoes. If only PN can upgrade all our cutters like this we would have fully armed navy vessels in our hands and combine it with this wildcat this would be practically the most modern equipment the AFP has ever purchased in the span of almost 30 years. The good thing is that it cost RP a fraction what a new frigate cost and can be delivered as little as a year. The bad thing is that it is old but what the hell at least it runs and its nasty. By the way did the dnd already choose the Incheon class as our 2 newest frigates? Will it be built in Subic? Because according to the Defense news updates it read Incheon class frigates. They look kinda dated compared to the Sigmas though.

      1. No new news yet on the Frigates. The picture I posted on the Philippine Defense News update about the next procurements just assumed that the Incheons will be purchased.

  6. ordering a new frigate will take years before it would be delivered. more or less 3 to 4 years. but what make these complicated pinoy term is near its end. and you know philippine politics whether the successors is from the administration or opposition, they will have their on agendas usually they will not follow the projects of the previous administration. we should pray under the term of pinoy we can order the new frigates or else another dim episode in the next administration.

    1. The Philippine Navy’s plan is to procure 2 Frigates during the next 2 Administrations, hence it will depend on the next Administrations if they will support this or not …

      1. Is it 2 frigates per new administration or 2 frigates total for 2 administrations? That is kinda sad unless they intend to pair it up with missile cruisers or subs or land based missile batteries. China is churning out a frigate or two every year. Just dont vote the leftists and pro china politicians hiding under the masa platform. They will sell us out if the price is right. Is there any update regarding the winning bidder for the frigate? Im excited what our new frigate looks like. Hopefully its not neutered by the budget and we get stuck with a a giant gunboat like what venezuela has.

      2. 2 Frigates every 6 years for a total of 6 Frigates. This was revealed in an interview of a Philippine Navy officer a couple of months ago. I can’t find that interview now, but I will post it here as soon as I find it.

        As for the procurement of other ships, the plan is there, but the clearest one so far are for the Frigates.

  7. difficult indeed…except for pinoy no one of our politicians cares about foreign affairs and our present external threats. if today no one voiced out against china for sure the next administrations are all timid and lack concern about nations security. if i were now in the administration or with the DND i will propose that all politicians will not be given automatic reserve officer commission, they have to sweat for it just like any other regular soldiers and those who were given the rank will be strip of the rank and if they want the rank they have to undergo basic military training and officer course training. its just a waste of giving them automatic rank of colonel to senators and congressmen but they lack patriotism.

  8. rhk111 its good you have this countdowns, it thrilled me to research also in advance. although not really that good about technicalities on military equipments and systems but same adding informations in your topics to come, it educates us.

    1. Great. I think the ARA San Luis blog is going to be a pretty good one, while the upcoming blog about large warships will have some surprises …

  9. indeed jmcenabre. people in here inspires me to never let this momentum of PH go for naught. at least in my own little way, i’ll see to that my voice is heard and made known to anyone that can be reached by me. It may not be big but if i go with significant numbers who have the same advocacy and fervor, I know I can be relevant along with those throng of patriots.

    1. Yes, it can attack both Ships or Submarines. In fact, it will be armed with the successor to the Sea Skua missile which will be out in a couple of years …

  10. if our 3 radar system we ordered from israel will be available by 2016, these will compliment the ASW helos. but israel promise us to lend 1 radar system in 2015 to fill up the gap. hope by then some of the fa-50 will arrive to test the capability of coordination between the land based radar system on our naval and air force component. i also comment in the page of “missile boat battle lessons” to take into serious consideration taiwan’s stealth missile boat KUANG HUA VI, capable of 33 knots in a diesel engine, has 4 anti ship missiles and decoy launchers. it is designed to cruise on low drafts in between islands or islets which is the situation in the west philippine sea whereby big warships have difficulty maneuvering. i think taiwan prepared this missile boats for that purpose.

  11. The finnish hamina class is also a nice alternative. It also has anti radiation sheilding as a bonus aside from its stealth ability. Plus it looks good.

  12. hamina is only designed to hug the finnish coast with a range of only 500 nautical miles. if we order hamina, just to bring it to our country is a logistical nightmare. and once it reached manila you have to escort hamina with a tanker if you want it to reach the spratlys. we cannot buy a weapon system something we cannot use in our situation specially of our long coast line. it is easy to say we stationed hamina nearer to the conflict but how about logistics to support its short range cruise. i might as well spend 100 million dollars to make the del pilar anti ship missile capable, ASW and CIWS and as well it can carry any ASW helos mentioned here that will fit its hangar. but since kuang hua also stealth technology and produce just near our backyard taiwan and has a range of 1,000 nautical miles and with a decent anti ship missile range of 160 kms is made for the situation in the west philippine sea. and let us start from there..we might develop our own once we get hold on the kuang hua,

  13. basing on our previous acquisition of taiwan made mpacs, i guess you have a point sir jmcenabre on being able to assemble our own. which could drastically lower the costs and open up employment. more work, more taxes thus more money to more hardware.

    Definitely, we should spend on upgrading on the del pilar frigates. because they will be our primary workhorse in the WPS patrols. though escorting them with a few missile boats is ideal. i think its best that our sea patrols should move at least in fours so that they can support eachother.

    but defintely we need a submarine like the Soryu class of Japan (really expensive but really capable. probably the best non-nuclear submarine).

    1. The Soryus are too large, and too expensive. The latest one was worth USD 540 million:

      The ones we can afford are simple Diesel-Electric Submarines, the cheapest right now are the U210 Ula-class submarine at around USD 250 million each, or South Korea’s Chang Bogo-class (variant of the Type 209) at around USD 360 million each. Submarines are expensive to maintain, though, requiring major overhauls about once every 8 years.

  14. That is indeed true. subs are quite expensive. the Soryus are the best possible sub that is not nuclear powered. though its expensive since it can use AShMs. you’re right though, owing to our budget, we should look into a decent torpedo only boat. would still deter the chinese into freely navigating into our waters.

      1. we should have a sub. if only to train our future submariners (yun nalang). we are the only south east asian country surrounded by water that does not have one. like the geagles lets start small (the cheapest but most modern one) then if the budget permits we get the next best thing. panakot lang muna. mostly they will be the escort of the 2 new frigates. in their spare time they could go sub hunting as a group. i can dream cant i?

      2. We need subs, it may be our only effective weapon against China, but it won’t be easy or cheap. Watch for my upcoming blog about that.

    1. Japan doesnt sell its offensive weapons abroad, the likes of submarines and mrf. Not that we can afford it either.

      Looks like the Type 209 from Germany or South Korea is preferable to us, based on its proven performance. I think we can afford one brand new, at a price roughly equal to the price of the 2 brand-new frigates that we are currently buying.

      But if cost is still an issue, we can always buy 2nd hand if we want the initial cost to be low.

  15. These 2 AW159 ASW choppers is a good buy for us. Not only can it drop torpedoes on enemy subs, it can fire missiles on ships, act as decoy for our ships who are being attact, and not to mention serving as an OTHT platform for the missile-armed MPACs.

    I also expect the AW109 to work in tandem with our soon-to-be-acquired P-3 orion.

    In fact, both platforms are critical in the WPS situation. We need to detect submarines, especially those who are supporting the Chinese white vessels in the stand-off area. If an enemy sub is detected, not only is this a sovereign violation of our territory, it will also violate the white-on-white principle of engagement.

    The situation suddenly becomes a military problem because the Chinese white ships can be interpreted as under the command or an extension of the military vessel, the PLAN sub. We can then ‘legally’ call in the our navy to reinforce the stand-off, or better yet, ask for some help from US navy ships stationed in the country by virtue of our MDT.

    1. Very good news, indeed. It seems that the ASW Helicopter project is moving forward and that they will soon announce the winner …

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