U.S. Air Force F-15s grounded again

WASHINGTON (Reuters) - The U.S. Air Force said on Tuesday it had grounded all its older-model F-15 fighter jets, about 450 aircraft, for the third time in four weeks, after finding another problem aircraft amid tightened inspections.

Air Force Secretary Michael Wynne told the Reuters Aerospace and Defense Summit in Washington that the latest F-15 "stand down" underscored what he called a need to extend Lockheed Martin Corp's (LMT.N) production line for the F-22, designed to replace the Cold War-era F-15.

A Defense Department spokesman said later there was no plan to extend the F-22, the top U.S. air-to-air fighter, beyond the 183 aircraft deemed by the Pentagon affordable and necessary, despite an Air Force request for more.

Wynne also said he expected the Air Force to gain an average of $20 billion a year, beyond its current budget, to buy warplanes at more economical rates over a coming five-year period starting in 2010.

"I think we will average about $20 billion a year and it will be a prudent ramp-up," he told Reuters Television.

"Our aging fleet and the progression of cracking that we're seeing is just not a good sign," Wynne said. "At some point in time we've got to stand them down and actually go ahead and buy the next-generation fighters."

Wynne said metal fatigue experts from the Air Force Research Laboratory found a crack Monday night in an F-15 undergoing inspection. It was in the same upper "longerons" spot tied to the November 2 crash of a nearly 30-year-old Missouri Air National Guard F-15C on a routine training flight.

Longerons run the length of the aircraft. The problem spot in the November 2 crash was near the aircraft's canopy, where cracks were found in follow-up inspections of three other F-15s, Wynne and other Air Force officials said.

After the November 2 crash, the entire F-15 fleet was grounded, then cleared to return to flight before being grounded again on November 28 amid concerns over possible fleet wide airworthiness problems for all but the F-15E, the most recent model.

About 30 percent of F-15A, B, C and D models had passed stepped-up inspections successfully, Wynne said, when the third aircraft with cracks turned up.

The Air Combat Command commander, Gen. John Corley, responded by ordering the latest stand down and recommending his counterpart U.S. commanders follow suit, said Maj. Thomas Crosson, a command spokesman.

Wynne said extending the F-22 production line was a "prudent hedge." The move would be a boost for Lockheed Martin, which faces closure of the line after 2011, when it is due to deliver the last of the 183 F-22s in current Pentagon planning.

Bryan Whitman, a Pentagon spokesman, said there was no change on the F-22 program in official Defense Department thinking, although people familiar with the matter have said in recent days that some Pentagon planners favor buying more.

"The program of record is 183 F-22s," Whitman told reporters. "That continues to be the program of record."

Jim McAleese of McAleese & Associates, a McLean, Virginia, national-security law firm, said it was "very likely" Congress would use several hundred million dollars meant to wind down F-22 production to instead buy raw materials to keep the line open.

Speaking at the Reuters summit, he predicted Congress ultimately would approve the purchase of as many as 240 F-22s, still down from the 381 the Air Force has said it needs.

(Additional reporting by Andrea Shalal-Esa; Editing by Tim Dobbyn)

(For summit blog: summitnotebook.reuters.com/)