Stealth Avionics

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To hear Northrop Grumman Corp. (NOC ) tell it, the B-2 Spirit stealth bomber is nearly invisible. It's "able to penetrate hostile space without being detected," the company boasts on its Web site. Further, it "does not need an armada of support aircraft to accomplish a mission." Why not? The plane's composite materials and bat-shaped design make it hard for radar to pick up.

So why were the $1 billion B-2s flying in the Balkans and Afghanistan accompanied by planes stuffed with electronics for jamming radar? It turns out that "stealthy" is a pretty relative description--as the U.S. Air Force discovered in 1999, when an F-117, which also has a stealthy shape and materials, was blasted out of the sky over the Balkans.

Stealth technology is hardly a sham. It shrinks the radar "signature" of a plane. If a conventional aircraft makes a blip on radar screens at 200 kilometers, a stealthy plane wouldn't appear until it was 34 km away. The point is, radar does eventually detect the plane, as do infrared devices--and plain eyes and ears.

Weather can also present a problem. The B-2's materials were tested at Edwards Air Force Base, where it rarely rains. But when the high-tech bombers got drenched during missions in the Balkans, the tape used to fill seams in the composite skin often came loose. That enlarges the radar signature.

So for now, the American military has taken to escorting B-2s with planes armed with radar jammers and missiles that can take out enemy radar sites. The bombers are capable of flying some of their runs alone--but only after radar and anti-aircraft weapons have been destroyed. Trouble is, both sides can play at stealth. Serbian forces were careful to use radar sporadically, effectively hiding it and preventing the U.S. from knocking out all the listening posts--and thereby curbing solo flights of B-2s.

All of this raises questions about the Air Force's plan to replace much of its existing fleet with stealthy aircraft such as the F-22 fighter, whose $99 million price tag is twice that of a conventional F-15. That's why the Navy rejected a stealth design for its new F/A-18 fighter, opting instead to rely on jamming. Less reliance on stealthy designs would free cash for more airborne jammers. They may be older and less sexy, but they still get the job done.

By Stan Crock

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