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‘Minor’ Flaw Shortens 2nd Stealth Flight

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Times Staff Writer

The second test flight of the B-2 Stealth bomber was aborted Wednesday after the controversial $530-million aircraft developed what Air Force officials termed a “minor problem” in its auxiliary power system.

Completing only one hour of a scheduled three-to-four-hour flight, the B-2 returned to Edwards Air Force Base at 8:36 a.m. when an indicator light in the cockpit signaled a low oil pressure condition in an “airframe mounted auxiliary drive.”

The aircraft has four of the auxiliary drives, which provide power to its hydraulic system, and any one of the four could have operated the hydraulic system, an Air Force official said. It was not clear Wednesday afternoon whether the drives had actually experienced low oil pressure or whether the indicator was giving a false reading.

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“Any time you get an indicator you come back and check it out,” Air Force spokeswoman Tech. Sgt. Cordelia Rackley said at Edwards. “The crew wasn’t in any danger.”

The bomber is in a political fight for survival in Congress, and each delay or anomaly in the test program is closely watched. The flight Wednesday came after an unsuccessful effort to fly Tuesday, in which the pilots exceeded their alloted time on duty after a series of delays for undisclosed reasons.

The bomber made its successful maiden flight July 17, after a one-day delay. Since then, Air Force officials, concerned about the attention paid to any flight postponements, have been debating whether to publicize each test flight in advance.

“We don’t want to be pressured into these flights until we’re ready to do them,” one official said. “It isn’t a matter that we want to be secretive or that it’s classified. But you can’t predict exactly when things are going to happen in a test program.”

Nonetheless, the B-2 program is under political pressure because of concerns about its cost and whether it fulfills a necessary mission. The Senate defense authorization bill for fiscal 1990 contains provisions that withhold funding for the B-2 if specific test milestones are not fulfilled. Those milestones include achieving certain flight objectives and proving that the aircraft can elude detection by radar, the capability at the heart of the Stealth program.

As a result, if the B-2 flight test program experiences a succession of delays, even minor ones, it runs the risk of falling behind schedule and losing funding for continued production of the planned fleet of 132 aircraft.

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The Stealth program will cost $70 billion, including about $22 billion already committed and the effects of future inflation. The bomber is designed to elude enemy radar through a combination of exotic materials used in its airframe and its complex shape. The aircraft is called a flying wing, because it lacks a conventional fuselage or tail.

So far, the minor delays and anomalies have apparently not raised red flags in Congress. “We haven’t heard any specifics of the problems today, but in flight testing there always are these sorts of things that come up,” one congressional staff member said Wednesday. “It isn’t anything that is going to raise any questions with us.”

The B-2 test program is expected to include 3,600 hours of flying and, with only three of those hours logged so far, the testing is still in a very preliminary stage, an Air Force official noted.

An Air Force statement issued at Edwards indicated that the B-2 successfully retracted and extended its landing gear in Wednesday’s flight, an important objective. The gear was kept down on the first flight, a standard safety practice on such tests.

In addition, the flight “envelope” was expanded, meaning that the B-2 flew higher and faster than on its first flight, but specific figures were not released. In the first flight, the aircraft flew up to 10,000 feet and never exceeded a speed of 207 m.p.h.

The B-2 has a quadruple redundant fly-by-wire digital flight control system, meaning that it uses electric signals rather than hydraulic lines or cables to operate its control surfaces. It was unclear exactly what systems are hydraulically controlled through the auxiliary drives.

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