Structural Flaws May Ground Older F-15s Indefinitely
Saturday, December 22, 2007
Air Force inspectors have discovered major structural flaws in eight older-model F-15 fighters, sparking a new round of examinations that could ground all of the older jets into January or beyond, senior Air Force and defense officials said.
The Air Force's 442 F-15A through F-15D planes, the mainstay of the nation's air-to-air combat force for 30 years, have been grounded since November, shortly after one of the airplanes broke into large chunks and crashed in rural Missouri. Since then, Air Force officials have found cracks in the main support beams behind the cockpits of eight other F-15s, and they fear that similar problems could exist in others.
Current and former Air Force officials said that the grounding of the F-15s -- on average 25 years old -- is the longest that U.S. fighter jets have ever been kept out of the air. Even if the jets are cleared for flight, they add, it could take six months to get the pilots and aircraft back to their normal status.
The grounded fighter jets do not include 224 F-15Es, which have been inspected and cleared. The E models, used to support the wars in Iraq and Afghanistan, are about 10 years younger and have a more robust frame.
The F-15A-Ds, meanwhile, are responsible for defending the United States, including flying combat air patrol missions over Washington, a job now filled by F-16s.
"This is going to be a major problem, and it's going to be a difficult one to recover from," said retired Air Force Gen. Dick Hawley, who led the Air Force's Air Combat Command from 1996 to 1999. "You could basically be without the nation's primary air superiority capability for an extended period of time, which puts us at risk."
The disclosure of the cracks comes amid intense Air Force lobbying for the purchase of additional new fighter jets. The Air Force wants to replace its aging F-15s with 200 more F-22 Raptors beyond the 183 already approved by Congress and the Defense Department. Senior Defense Department officials have not agreed that the additional planes are needed or supported their purchase. The F-22s, which cost $132 million each, are manufactured by Lockheed Martin, a Bethesda-based firm.
Significant cracks have been found in the longerons, or structural beams, that support the F-15 fuselage, Air Force officials said -- damage that is believed to be connected to the intense stresses placed on the planes during decades of high-speed maneuvers. The crash last month happened after the back of one plane was ripped off behind the cockpit during a 500-mph dogfight practice. An official crash investigation is scheduled for completion soon.
Some outside analysts have said that the F-15 problems can be fixed and that the extra F-22s are unnecessary. "I don't suspect that the Air Force is lying when it says it has discovered stress fractures in the longerons of the F-15s," said Winslow Wheeler, an expert at the Center for Defense Information and a longtime opponent of purchasing additional F-22s. "But there's no big deal about that. Fix it."
Wheeler said Congress should look into the F-15 issue. In another prominent case, involving refueling tankers, several independent study panels concluded that the Air Force had exaggerated the structural consequences of aging for older planes so that it could make a better case for leasing new ones.
Air Force photos of the damaged beams show clearly visible cracks toward the rear of the fighters' cockpits. Photos and drawings provided to The Washington Post show cracks in similar locations on both sides of the planes and that the F-15 that crashed had undetected damage behind the cockpit.
Maj. Stephen Stilwell, 37, of Missouri was taking that F-15 through basic dogfighting maneuvers Nov. 2 when he started an abrupt turn. At nearly 8 Gs and 500 mph, something went horribly wrong.
"I heard a big rush of air, very loud, like a tornado ripping the roof off a house," Stilwell said. The jet then felt as though it was fishtailing before Stilwell was thrown violently, smashing his left shoulder to pieces. "It was like I was in a car and it's flipping down the road. I felt like the airplane was tumbling and I'm being slammed around, left, right, front and back. . . . It was like I hit a brick wall at 450 miles per hour."
Stilwell's plane had split into two pieces and was hurtling to the ground -- the rear of the craft crashed half a mile from the cockpit and nose. He ejected and parachuted into a wooded area.
"It was the craziest roller coaster I've ever been on," said Stilwell, a commercial pilot with eight years of fighter experience in the Air National Guard.
Similar stress fatigue has been since found in eight airplanes. Four of the damaged aircraft were at the Oregon Air National Guard's 173rd Fighter Wing at Kingsley Field, one of the country's two F-15 training bases. All 25 of the wing's F-15s have been grounded for six weeks.
"The hope is that they will fly again," said Capt. Lucas Ritter, a spokesman for the 173rd. "But we don't have a time frame for when that will be."
Inspectors plan to expand their investigation to include larger areas of the support beams. Senior Air Force officials said that it is unlikely that the entire fleet will be grounded indefinitely but that they are concerned.
"We haven't seen a failure like this before," said a senior Air Force officer, who spoke on the condition of anonymity because the crash investigation is not complete. "I would say it's hard to imagine a more catastrophic event."
Military officials have passed along warnings to foreign countries that have purchased F-15s, including Israel, Japan and South Korea.
Retired Gen. Gregory S. Martin, who led the Air Force Materiel Command from 2003 to 2005, said the F-15 was not designed to last the 30 years it has.
"In my opinion, based on the engineering data we had, we should not be surprised that we're finding some failures in the major structural areas of the airplane," Martin said. "The question wasn't if they would fail, it was when those failures would occur."
Maj. Gen. P. David Gillett Jr., the Air Combat Command's director of logistics, said the Air Force is doing what it can to balance pilot safety with the need to protect the nation. "It's got some problems, but we're going about restoring that capability as quickly as we can," Gillett said.