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Debate rages as military seeks to counter transport aircraft threat
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| 05 June 2006 |
By Bill Sweetman, IDR Technology and Aerospace Editor
The most effective and expensive countermeasure for man-portable air defence systems (MANPADS) is a directed infrared countermeasures (DIRCM) system, comprising missile approach warning systems that cue a turreted tracker and light source to jam the missile seeker with IR radiation. So far, DIRCM is considered to be the only onboard system that can effectively protect the aircraft against all kinds of IR missiles. Unlike the old-generation pulsed-lamp systems, modern DIRCM are not specifically aimed against the reticle-scanning IR seekers used by older MANPADS.
First-generation DIRCM systems, like the Northrop Grumman/Selex AN/AAQ-24(V) Nemesis, used xenon arc lamps to provide jamming energy and are in use on a wide variety of aircraft. However, Northrop Grumman now says that the original version is out of production, replaced by versions of the AN/AAQ-24(V)13 Large Aircraft IRCM (LAIRCM) system. First fielded on the C-17 in May 2003, LAIRCM was developed to meet a 1998 requirement for a more powerful IRCM system that could protect bigger, more powerful, multi-engine aircraft, which have a more prominent IR signature than smaller aircraft.
The US Air Force elected to meet the LAIRCM requirement by adapting the existing Nemesis system, to incorporate a higher-energy laser jammer. The chosen laser was a lightweight, multiband system known as Viper, developed by Fibertek Inc. Viper is a solid-state diode-pumped Nd:YAG laser that can operate in up to three segments of the mid-IR waveband.
The biggest issue in the DIRCM is whether this type of system will be adopted on a large scale to protect commercial aircraft. Scepticism about the value of DIRCM on commercial aircraft has been led by the Air Transport Association (ATA), with support from a 2005 report from the Rand Corporation. As ATA executive vice-president John Meenan sums up the issue: "The contest is larger than counter-MANPADS, and at the end of the day, resources are not without limit." Rand estimated that the cost of retrofitting the 6,800-aircraft US fleet at USD11.2 billion and that the system would cost USD2.1 billion per year to operate - half of the entire US budget for transportation security.
The ATA's concern, firstly, is that terrorists will simply bypass the defences by continuing to attack aircraft in other ways - with bombs or unguided weapons, for instance. "Why aren't we dealing with the threat of direct-fire weapons?" such as unguided rockets or small arms, Meenan asks. "Because there is no solution and industry is not out there selling it."
Other issues involve the deployment of a counter-MANPADS system. The DHS plan calls for aircraft assigned to the Civil Reserve Air Fleet to be modified first, followed by those aircraft that operate into less secure airports. However, as Meenan notes, airlines operate their aircraft flexibly. A further paradox is that while it might seem logical to protect bigger aircraft first, because they are more valuable and carry more passengers, the record clearly shows that larger aircraft are much more likely to survive a MANPADS hit.
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