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Air Force examines whether F-15 maker is liable for crash

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Times Staff Writer

The Air Force is reviewing decades-old contracts to determine whether manufacturers of U.S. fighter jets bear responsibility for a defect that caused one of the planes to break apart in flight late last year, officials said Thursday.

An investigation of the November crash of an F-15 showed that one of several support beams in the plane was thinner than design specifications required. That faulty part caused a failure that split the plane in two.

The downed plane was built in 1980 by McDonnell Douglas Corp., which merged with Boeing Co. in 1997. Boeing officials participated in the crash investigation and helped identify the structural failure that led to the mishap, Air Force officials said.

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Patricia Frost, a spokeswoman for Boeing’s F-15 business, declined to comment on the crash investigation. The company is waiting for the final analysis of the approximately 180 F-15s that remain grounded.

Air Force officials said Boeing’s potential liability was difficult to determine because of a complex contracting history and the age of the aircraft.

“Our question will be: What was the contractual arrangement at the time, and is there still residual liability?” Lt. Gen. Donald Hoffman, the Air Force’s top acquisition officer, told reporters Thursday. “We have to prove that the flaw had significance.”

F-15s originally were designed to last 4,000 flight-hours, then were upgraded to last 8,000 flight-hours. The F-15 that crashed had 6,000 flight-hours.

The Air Force grounded all of its F-15s after the crash. The newest planes, Model E, were quickly returned to service, but 441 older models remained grounded until Wednesday, when the Air Force returned about 260 of them to service.

The Air Force said the planes that remained grounded had flaws in a crucial part called a longeron, a structural beam that serves as part of the spine of the aircraft. F-15s have four longerons around the cockpit.

Some of the longerons are too thin, or have ridges or rough surfaces that put too much stress on the structure, officials said. Some longerons diverge a bit from design specifications; others have larger flaws.

The Air Force expects to complete the structural analysis of the planes in about four weeks.

Gen. John D.W. Corley, the head of Air Combat Command, emphasized that age as well as the defective part contributed to the crash.

“Don’t lose sight of the fact this is not just a bad part, it is a bad part that has been under stress for 25, 26, 27 years,” Corley said. “It is the interaction between the fatigue, stress and that part that causes the crack.”

Corley said it would cost about $250,000 to replace each faulty longeron. But the repairs could prove more expensive than that, and many Air Force officials question whether all of the planes should be repaired.

“We have to ask ourselves: Can they be replaced? Is it smart to replace them?” Corley said.

Some of the planes, Corley said, may be so close to the end of their service life that it would not make sense to repair them.

Replacing them may not be a popular option with Air Force officials either. They hope to replace the F-15s with new, faster and more sophisticated F-22s.

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julian.barnes@latimes.com

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