Arming the new Light Strike Aircraft

A couple of days ago I wrote about the USAF's proposed new Light Strike Aircraft, and examined the proposed Hawker Beechcraft AT-6, currently under development, and the Embraer EMB-314 Super Tucano, as potential solutions to this requirement.

Several readers e-mailed me with rather negative comments about such aircraft. A common thread was that they didn't carry enough ordnance to provide adequate support to troops in contact. As one correspondent pointed out:

In Vietnam, the Douglas A-1 Skyraider [which we examined in depth in Weekend Wings #31] carried up to 8,000 pounds of ordnance on up to 15 hardpoints beneath the fuselage and wings. The proposed AT-6 will have only six underwing hardpoints, plus (presumably) one beneath the fuselage. It's unlikely to carry more ordnance than the Super Tucano, which has a payload less than half the Skyraider's. That's not enough. Neither aircraft can carry enough weapons to get the job done.

I can understand my correspondents' concerns, but I submit they're misplaced. They haven't taken into account the development of weapons over the past couple of decades, which have revolutionized effectiveness and efficiency. Let's examine just a few of the weapons such a Light Strike Aircraft could employ.


1. BOMBS

The old-fashioned 'dumb bombs' in 500lb., 1,000lb. and 2,000lb. weights were ubiquitous in Vietnam - and highly wasteful. Tens of thousands of bombs were dropped on empty jungle in what disgruntled pilots called 'making matchsticks'. Given their inability to identify and locate the target precisely, pilots had to drop multiple bombs over an area to neutralize whatever threat lay within it. Even with so profligate an expenditure of ammunition, they weren't always successful.

'Smart' bombs made their first appearance towards the end of the Vietnam war, and came to prominence in Operation Desert Storm. Since then, they've largely taken over most strike roles. The same bombs as were used in Vietnam are employed, but are now fitted with guidance systems and winglets, so that they can glide to a precisely-designated point (either under Global Positioning System (GPS) guidance or directed by a laser target designation system) and destroy it. One 'smart' bomb can now destroy a target that might have survived twenty to thirty 'dumb' bombs in the past.

Given this increased accuracy, it didn't take long for someone to work out that the size of the bomb could now be tailored to the desired result. It didn't make much sense to drop a 2,000 pound bomb on a group of infantry in a trench. Sure, it'd dispose of them, but much of the blast would be wasted. A 500lb. weapon would do the job just as efficiently. In the same way, a tank might be destroyed by a 500lb. bomb, but that was still 'too much gun'. A bomb half the size would be adequate for the job, provided it could be placed accurately on target.

This has led to the development of the newest generation of 'smart bombs', the so-called Small Diameter Bomb (SDB).




This 250lb. weapon is much smaller than earlier bombs, but just as lethal, since it can be guided to its target by either GPS signals or a laser designator beam. No less than four SDB's can be carried on a rack in the space formerly required for a single 1,000lb. or 2,000lb. bomb.

Four rack-mounted SDB's loaded on a single pylon beneath an F-15E Strike Eagle

The SDB's fuse can be set to detonate above ground, producing a shrapnel effect; on impact, producing a surface blast; or at a preset interval after impact, allowing it to penetrate deep into the earth, or through reinforced concrete defenses, before exploding. The two pictures below show an SDB being tested against a reinforced concrete aircraft bunker. It penetrates all the way through the protective bunker before exploding.






Some may criticise the SDB for being 'only' 250lb in weight, but I don't think that aircraft's going to be flying anywhere after that little encounter!

Here's a video clip of the SDB, going into more detail about how it works. I apologize in advance for the breathless "oh-gee-whiz!" commentary, but that's modern television for you. If the announcers would just shut up and let the designers and engineers tell the story, it'd be much better!

Two new versions of the SDB are under development, and will be deployed in the near future. One, referred to in the video clip, will have a multi-mode seeker head, enabling it to acquire and attack moving targets. The second, the so-called Focused Lethality Munition (FLM), has a carbon-fiber casing and multi-stage explosive warhead, designed to minimize shrapnel and collateral damage, and focus the entire blast on the specific target. Here's a video clip of an early test of the FLM.

As mentioned earlier, an aircraft weapon station that previously carried a single large bomb can now carry up to four SDB's, quadrupling its effective bomb load. That's going to be very useful for the proposed Light Strike Aircraft, with its lower payload.


2. ROCKETS.

Unguided rockets have been a staple of close air support since the later years of World War II. The US has employed 2.75" rockets of various types, the current iteration being known as Hydra 70. They're mounted in 7-tube M260 or 19-tube M261 launchers on US Army attack helicopters, such as this M261 mounted on an AH-64 Apache. (The rockets shown are of different lengths, due to different warheads fitted to them.)




The main problem with these rockets has been their lack of guidance. A salvo of many rockets has typically been required to destroy a target, and the tendency of some rockets to 'wander' off-course has caused more than a few gray hairs among friendly forces on the ground!

As a result, and given the advances in weapons guidance systems, a large number of projects are under way to add guidance systems to the 2.75" rocket, making it a precision munition in its own right. Among the current programs are the Advanced Precision Kill Weapons System (APKWS), currently being run by the US Navy; the CRV-7 Rocket Weapon System; the Direct Attack Guided Rocket (DAGR); the Guided Advanced Tactical Rocket - Laser (GATR-L); the Laser Guided Rocket (LGR); the Low-Cost Guided Imaging Rocket; and the Roketsan Cirit. This is far from a US-only effort: nations such as Israel, South Korea and Turkey are involved in some of these projects, and it's a virtual certainty that other nations (including Russia and China) are engaged in similar work.

We can't possibly look at all these programs in detail in a short blog post, but they all involve fitting a guidance kit onto a standard 2.75" rocket. Let's look at one in detail, the Direct Attack Guided Rocket (DAGR) (shown below), being developed by Lockheed Martin.




Lockheed are developing an innovative 4-round launcher for the DAGR (shown below), each of which can fit onto the same bracket used to launch a single AGM-114 Hellfire anti-tank missile. Thus, a 4-round Hellfire launcher, as illustrated, can handle up to 16 DAGR rounds, or a mixture of DAGR and Hellfire weapons.




DAGR has already been successfully tested on the ground and aboard two models of helicopter. Here's a video clip showing early ground tests. Note the exceptionally good accuracy obtained against targets.

DAGR and similar rockets will probably also be able to be launched from standard rocket pods. In anticipation of these being used on aircraft faster than typical attack helicopters (such as the proposed Light Strike Aircraft), at least one company is developing streamlined rocket pods that will cause less drag at higher air speeds.

With such accurate rockets, the Light Strike Aircraft will be able to hit multiple targets with one or two rockets each, rather than the 'spray-and-pray' technique used with unguided rockets. This will make its payload far more effective, and - as with the SDB - it'll be able to deal with more targets for a given payload than was previously the case.


3. MISSILES.

It's a virtual certainty that the Light Strike Aircraft will be able to launch guided missiles such as the AGM-114 Hellfire and similar weapons, and perhaps even the much larger AGM-65 Maverick. However, these are not ideal close-air-support weapons. They're great at killing tanks, or taking out hardened structures: but for troops in combat, they're often too big for the job that needs doing (just as 500lb. or 1,000lb. bombs are 'overkill' for many targets). I'd expect the Light Strike Aircraft to carry relatively few such weapons, reserving them for important targets, while using guided rockets (as described above) for less resistant targets. It may also be that new versions of the SDB coming into service will render such missiles redundant in the close air support role.



4. CANNON AND MACHINE-GUNS

Some believe that a ground-attack and close-air-support aircraft must necessarily have a heavy gun armament, in order to strafe enemy positions. This is certainly useful, but with the advent of precision guided weapons, I suggest it's less important than in times past. The Embraer Super Tucano has two .50-caliber machine-guns in the wings. The AT-6, as I understand it, won't have integral guns in the wings, but can carry a cannon or machine-gun in a pod on a weapons station beneath the wing or fuselage. This would also allow for a heavier weapon than a machine-gun to be fitted, without worrying about internal space constraints.



5. OTHER WEAPONS.

Perhaps one of the most interesting developments in recent years is that remotely-fired and -controlled weapons are now entering the scene. These can be pre-positioned, or trucked to a safe location by transports, and called upon when the warfighters need them.

Two examples have so far received publicity. One is the Non-Line-Of-Sight Launch System, being developed for US forces by Lockheed Martin and Raytheon in partnership. It's a box known as a Container Launch Unit (CLU), holding 15 missiles with a range of dozens of miles. The CLU can be transported aboard a truck, and fired from there, or lowered to the ground for use. Here's a picture of a missile being fired from a truck-borne CLU.




Two missile types are under development for use in the CLU. The Precision Attack Munition will have a range of about 25 miles, and have a guidance system using GPS and/or laser designation and/or autonomous infrared imaging. The Loitering Attack Munition will have a longer range of over 40 miles, and will fly to a pre-designated area and loiter overhead for up to 30 minutes while seeking targets.

Here's a video of the NLOS-LS. Again, apologies for the breathless excitement of the commentator!

Israel has developed a similar system, called Jumper (shown below). It has eight missiles in its container, each with a range of over 30 miles.




It's highly likely that the USAF's Light Strike Aircraft will be equipped to call on such missiles to attack targets it designates. The missiles can be simply 'dumped' in a convenient location (perhaps a hilltop firebase, or something like that) and left there to be activated when needed. They don't need a crew, or local intervention to fire them.


So, the Light Strike Aircraft will have a considerable variety of munitions at its disposal, either carrying them itself, or able to call on them from outside sources. Even with only six under-wing and one under-fuselage hardpoints, it could carry up to eight SDB's, plus up to eight DAGR's (or even more if higher-capacity rocket pods are developed), a couple of Hellfire missiles, a gun pod, and a targeting pod. That's an awful lot of firepower!

It might not even need to use its own weapons. Let's take an example of a US patrol ambushed by enemy forces in the mountains of Afghanistan. Due to the mountains interfering with radio communications, the patrol can't call on systems like the NLOS-LS for itself. It could begin its counterattack by using its own miniature UAV, such as (for example) the RQ-11 Raven currently in service (shown below), to precisely locate enemy positions.




While doing this, the patrol would call for air support. A Light Strike Aircraft (or more than one), loitering in the area or on call at a nearby base, would speed to their location. On the way, the aircraft would receive information from the UAV about enemy positions. On arriving overhead, the aircraft would verify this information, using its more comprehensive electronic systems, and either establish the GPS co-ordinates of the targets or stand by to designate them with its laser targeting pod. It would then, from its higher altitude (which eliminates the problem of interference from intervening mountains), transmit instructions to an NLOS-LS CLU, up to 20 miles away or more, to fire a number of missiles. Those missiles would transit to the engagement area, take their targeting data from the aircraft, and dive onto the targets, destroying them. The aircraft might never need to use its own weapons or descend to within range of enemy fire.

So, with the greatest of respect to my correspondents, I think that the close-air-support scenario has changed so much since the days of Vietnam and the Skyraider that the lesser payload capacity of aircraft such as the AT-6 or Super Tucano is no longer a drawback. On the contrary - if one tried to load a Skyraider to full payload capacity with modern, compact weapons, one might come back after most missions with more than half the ordnance unexpended!

Peter