The world's most expensive aircraft flew into battle for the first time yesterday as a pair of $2.1 billion B-2 bombers struck targets in Yugoslavia with 2,000-pound satellite-guided bombs.

The black planes left their climate-controlled hangars at Whiteman Air Force Base, Mo., flew nonstop to Kosovo with several midair refuelings and attacked multiple "hardened" targets, including command bunkers and air-defense systems, defense officials said.

Each plane dropped a maximum load of 16 bombs, said Brig. Gen. Leroy Barnidge Jr., commander of the 509th Bomb Wing at Whiteman. There was no immediate information on damage, but Barnidge said that, generally, "we measure miss distances with a yardstick."

"It's about time," said John Pike, a defense expert at the Federation of American Scientists. After the Air Force spent almost $45 billion to develop and buy just 21 planes, "they'd better use it," he said.

Created in secrecy beginning in the late 1970s, the bat-like, tailless plane was built by Northrop Grumman Corp. and was not even acknowledged to exist until 1988. The B-2's exotic shape and surface coatings make it all but invisible to radar.

Its great range of up to 6,000 miles without refueling was originally intended to allow the plane to deliver nuclear warheads deep inside the Soviet Union. Since the end of the Cold War, the B-2 has been criticized for its cost, the durability of its radar-absorbing skin and the relevance of its mission.

Even the Air Force has resisted buying the bomber because it wants the money for new fighters such as the F-22. But persistent supporters in Congress kept the program alive, though the 21-plane fleet is down drastically from the 132 originally envisioned.

The Air Force certified the B-2 for both conventional and nuclear missions in 1997, but the plane was ignored during bombing raids in Iraq and elsewhere.

"For a long time, many of us who supported this aircraft had the impression the Air Force was unwilling to use it in anything other than a national emergency," said Loren Thompson of the Virginia-based Lexington Institute defense think tank.

The common belief, Thompson said, was that the Air Force was afraid to risk losing one of the expensive bombers -- any one of which was worth more than the cost of 80 F-16 fighter jets.

The NATO action in Kosovo finally supplied a mission worthy of the plane's unique capabilities, said Richard Aboulafia, a military aircraft expert with the Teal Group consulting firm in Fairfax, Va.

Yugoslavian air defense systems are far more concentrated and prepared for an attack than are those in Iraq, he said. Only the B-2 could allow pilots to sneak past safely and still deliver a heavy load of bombs.

The B-2 is also the only plane that can carry large numbers of the most advanced, satellite-guided "smart" bombs, and those weapons are necessary in Yugoslavia because the weather is so bad, said Pike.

"Those bombs aren't worried about cloud cover," he said.

While the Air Force has beat back criticism that the B-2's special coatings will wear off in a rain storm, the plane does have special requirements. The most significant limitation: a B-2 is virtually defenseless in case of attack.

The planes are slow -- they fly slower than the speed of sound -- and have no guns or air-to-air missiles.

"Anything that can fly can kill this thing," Aboulafia said.

Of course, any adversary would have to see the plane to shoot it down -- and that is no easy matter. Even during the day, the thin profile of a B-2 is almost invisible to the eye, and in combat the planes fly only at night.

The bomber's engine exhaust is dampened to make it both quiet and difficult to pick up on heat-seeking scopes.

"If I was a pilot driving into this [conflict], I'd rather be riding on the B-2 than anything else," Pike said. "There is certainly less chance of the B-2 being shot down than anything else being shot down."

Still, the experts said there is little likelihood that a successful outing in Yugoslavia would cause Congress to restart the B-2 production line.

"I think the issue of future B-2 bomber production is essentially over. The supply chain is gone, and the equipment to build it has largely been turned to other uses," Thompson said.

Pub Date: 3/25/99