NORTHROP WORKS TO FIX B-2 CRACKS CRAFT STILL SAFE, AIR FORCE SAYS.

Byline: Jim Skeen Staff Writer

PALMDALE - Sixteen of 21 B-2 stealth bombers have developed cracks on their rear decks, but the Air Force is saying the defects do not compromise the bombers' safety or stealthiness.

Cracks up to 9 inches long were found on the aft decks of the aircraft, behind the engine exhausts. The cracks are being monitored while a long-term fix is being developed, officials said.

``Yes, there are cracks, but there are not a safety-of-flight issue and they are not affecting the aircraft's stealthiness,'' said Air Force spokesman Rob Koon.

The cracking is the recurrence of an old problem. Similar cracking was reported in 1990, prompting design changes and patching work costing $200 million.

The Air Force and Northrop Grumman, the prime contractor of the B-2, have been working on the new cracking issue since at least October 2000. A team comprising Northrop Grumman and the Air Force's Aeronautical Systems Command is working to find a long-term fix for the cracking.

``We are looking at the matter,'' said Northrop Grumman spokesman Jim Hart.

In the meantime, the cracks are being checked at the end of each flight day. B-2s that have not had cracks are being checked every 200 flight hours, Koon said.

In a separate matter, a Pentagon report says the B-2 still has maintenance requirements that cut into its availability for missions. In an annual report to Congress by Thomas Christie, the Pentagon's director for operational test and evaluation, the B-2s were available an average of only 31 percent of the time.

Pentagon officials have praised the B-2 for its effectiveness in combat in Kosovo and more recently in Afghanistan, but have been critical of the lengthy maintenance times involved in replacing specialized tapes and caulking around access panels. The materials have lengthy curing times.

Northrop Grumman has developed a spray-on coating called alternative high-frequency material that will replace much of the tapes and caulking. The time for removing and replacing an access panel for the aircraft will be reduced from several hours to just minutes.

``We believe this will improve the maintainability of the aircraft,'' Hart said.

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Photo:

(ran in Business section only) B-2 stealth bombers, like the one seen in this file photo, have developed cracks on their rear decks. The Air Force and Northrop Grumman, the prime contractor of the B-2's, are working together to repair them.