Air Force Indefinitely Grounds Many F-15 Jets
Friday, January 11, 2008
The Air Force will keep more than 40 percent of its older model F-15 fighter jets grounded indefinitely after discovering that critical support beams have manufacturing flaws dating back nearly 30 years that could lead to catastrophic damage to the aircraft.
Air Force officials announced yesterday that the metal beams on 162 of the fighter jets have flaws -- such as being too thin, too rough or improperly cut -- adding that high-stress flight over the past three decades has exposed the problem. The discovery came after an F-15C ripped into two large chunks on a training mission over Missouri in November, leading investigators to pore over the wreckage and order inspections of the 450 other F-15 A-D models. The planes were initially grounded that month.
Air Force officials announced yesterday that they are investigating possible liability on the part of Boeing, which purchased the original manufacturer of the airplanes -- McDonnell Douglas -- in 1997. The planes that have been found to have defects were built from 1978 to 1985.
The Air Force's 224 newer F-15E fighter jets do not have the same flaws and have been returned to service. This week, the Air Force returned 261 F-15 A-Ds to service after they were cleared for flight.
Although some of the flawed beams -- known as longerons -- have been deemed just millimeters off of their blueprint specifications, Air Force officials said they are not taking chances with aircraft that could be susceptible to the same cracks that led to the dramatic crash last year. Nine of the F-15 A-D models have been grounded because of actual cracks in the aircraft; Air Force officials said yesterday that they are weighing the possibility of replacing the longerons on the other defective planes or giving up on the aircraft in favor of $132 million F-22s, a cutting-edge fighter that the Air Force prefers.
Lt. Gen. Donald J. Hoffman, a military deputy in the Air Force acquisition office, said the Air Force is beginning to investigate potential liability on the part of the manufacturer, but Air Force officials also said they are having difficulty locating the original contracting paperwork and are unsure whether McDonnell Douglas made the specific part that is failing or whether it was made by another vendor for inclusion in the airplanes.
Paul Guse, a Boeing spokesman, said yesterday that any potential issues of liability will be dealt with by "the appropriate parties" and that "it would be inappropriate for Boeing to speculate or discuss those issues at this time."
Boeing officials said they have been working with the Air Force to determine the extent of the problem, and the Air Force said Boeing tests led to the discovery of the manufacturing defect after the November crash. By failing to conform to blueprint specifications, the metal beams in some cases weakened and cracked after years of experiencing high speeds and G-forces, according to the accident investigation. Guse said Boeing is gathering data from its F-15 inspections and expected it to take about four weeks to determine a course for fixing the aircraft.
Gen. John D.W. Corley, head of Air Force's Air Combat Command, told reporters at the Pentagon yesterday that the F-15 problems amount to a "crisis" affecting the nation's "workhorse" fighter jet responsible for defending U.S. airspace. Corley said there is no pattern connecting the apparent manufacturing defects, as they span different production years, and that there is no way to detect the problem without pulling the aircraft apart for close inspection.
"This is not isolated," Corley said. "This is systemic."
Animated videos released yesterday show how the F-15 that crashed last year experienced its cockpit sway and then shear off in mid-flight during a simulated dogfight, sending the two pieces of the jet crashing to the Missouri farmland about half a mile apart.
In an interview with The Washington Post last month, the jet's pilot said it felt as though the airplane fishtailed before sending him tumbling in the cockpit at more than 500 mph. Radio transmissions played at a Pentagon news conference yesterday suggested how dramatic the incident was, with the pilot's wingman urging him to eject after witnessing the plane breaking up. The pilot ejected from the cockpit after it separated from the rest of the plane, and he parachuted to safety.