What’s The Buzz

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The attacks on several U.S. military helicopters in Iraq in recent weeks has put hardening these aircraft against attempts to bring them down back in the spotlight.

The spate of helicopter combat losses by ground fire, with the associated loss of soldiers’ lives, rekindles a concern that had taken center stage more than a year ago. But worries at the time subsided when incidents became rarer after
U.S. pilots started employing new tactics and helicopters were kitted with enhanced self-protection systems.

 But events this year indicate still more needs to be done, particularly when trying to counter less-sophisticated systems, such as small arms fire. The Pentagon plans several further enhancements to its helicopter fleet to strengthen self-protection capabilities. It also is looking at non-traditional approaches to spoof potential attackers. 

One of the more unorthodox ideas being advanced now is the development of a system that would sound like a helicopter and have the same heat-signature, but in fact be no more than a small unmanned aircraft. The idea is to fly the drone in a potentially hostile area and trigger a threat that otherwise could be used against a real helo.

The idea of using decoys to fool air defenses isn’t a new one. The Pentagon has been working with various versions of airborne decoys for years to help protect fighter or bomber aircraft from higher-end, radar-guided air-defense systems. But what is a chance is expanding the operational concept to helicopters, which operate much closer to the ground and are primarily exposed to a completely different type of low-tech threat.

Darpa, the Defense Advanced Research Projects Agency which acts as the Pentagon’s in-house technology incubator, is starting up the program called the Battlefield Helicopter Emulator. Darpa concedes there are still hurdles that need to be overcome. Nonetheless, the vision for such a system is to “enable the military to locate and harmlessly engage anti-helicopter mines, man-portable air defense systems, and provide a source of confusion during special operations.”  

Although the stated concern is about anti-helo mines, which are often triggered by noise and then launch a projectile in the air to damage the rotorcraft, as well as the manpads — the shoulder-fired, heat-seaking missiles used on several attacks on military and commercial airliners in recent years — a unmanned aircraft-based decoy system could also be used to lure into the open individuals wanting to attack a helicopter with small arms or other devices. 

The decoy is supposed to be able to mimic a variety of helicopter types, from the Sikorsky UH-60 Black Hawk that serves as the backbone of troop transport for the
U.S. military, to the MD500, which is the basis for the Army special operations AH-6 Little Bird attack helos. 

Developing the technology will not be quick nor easy. Field testing of such a device may be four years off, with some of the basic technology only being demonstrated next year. One of the challenges is to properly duplicate the sound of the main rotor and tail rotor, which means getting the noise ratio and harmonics just right. Similarly, replicating the heat (or infrared) signature of helicopters of different models also isn’t trivial. 

The decoy effort isn’t the only or first move to boost self-protection systems. The Naval Air Systems Command, for instance, which manages Navy and Marine Corps helicopter programs, is embarking on another round of upgrades using more traditional systems. In 2004, the organization shifted priority from funding advanced fighter self-protection equipment to helicopters.  

Now, according to a colleague at Aviation Week & Space Technology, the Marine Corps plans to put a laser-based IR-countermeasures systems, similar to the one already used on some Air Force C-17 transports, on its CH-53E troop-hauling helicopter workhorse. The upgraded helos should be in the field in about a year’s time. But those systems are designed to counter heat-seeking missiles, and will do little against less sophisticated systems that have been the source of the latest shoot downs. 

Other efforts are also underway. One example is an activity
Bulgaria is leading under the umbrella of the North Atlantic Treaty Organization. The work focuses on developing a system to protect rotorcraft against the ubiquitous RPGs (rocket propelled grenades). With heat-seeking missiles, the countermeasures generally fool a missile into chasing a false target. The challenge with RPGs is that they don’t have any smarts that can be spoofed in that manner, so the projectile has to be intercepted or deflected some other way. But those systems, which exist for ground vehicles, are large and heavy, and finding an airborne version that’s operationally suitable remains to be achieved.
 

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