| Submit your comments on this article |
| Home Front: WoT |
| Flaw may permanently ground 160 jets, Air Force general says |
| 2008-01-11 |
| I'm not sure where to put this. It probably needs refiling! A manufacturing defect blamed for the mid-air breakup of an F-15 Eagle fighter may cause the Air Force to ground a quarter of its fleet of those warplanes permanently, a top general said Thursday. Gen. John Corley, the head of the U.S. Air Combat Command, said about 160 of the jets may never return to service after an investigation into the November 2 crash that left the plane's pilot seriously injured. The single-seat F-15C broke up in a 500-mph turn during a combat training mission over Missouri, with its fuselage breaking in half behind the cockpit, an Air Force probe of the crash determined. Investigators concluded that a critical piece of the jet's airframe broke during the flight because of a manufacturing defect. A defective longeron -- a metal strut that runs lengthwise down the fuselage -- was cut improperly by the manufacturer, Boeing, and led to a series of cracks over the plane's lifespan, Corley said. "Some of these airplanes will never return to flight," Corley said. "The age, the fatigue on these airplanes has been manifest as we looked under the hood extensively over these last two months." The Air Force has been flying the twin-engine, supersonic F-15 since the early 1970s. The C model involved in November's crash is credited with 34 of the 37 "kills" credited to Air Force pilots in the 1991 Persian Gulf war, according to Thursday's report on the accident. The service has about 700 F-15s in its fleet, all of which were grounded after the November crash. Most were returned to service after being checked out, but about 40 percent of the Air Force's 442 F-15 models A through D remain grounded. "I flew these airplanes 30 years ago," Corley told CNN "This is a fleet of airplanes that's 25-plus years old on average. That constant pulling and pushing and twisting has also caused fatigue." If the grounded planes are retired, the Air Force would still have about 240 of the older fighters and nearly 300 of the newer F-15E, a two-seat version used for ground-attack missions in Afghanistan and Iraq. Investigators released the results of the Missouri crash at a news conference Thursday in the St. Louis suburb of Bridgeton, home of the Air National Guard wing involved in the accident. The pilot, 37-year-old Maj. Stephen Stillwell, told reporters that his plane broke up in a turn that produced about eight times the force of gravity. "I had no idea what was happening," he said. "I knew something bad was happening, but I didn't know what it was." Stillwell suffered a broken arm and still has problems with his shoulder. He credited his survival to the training he received. "You always prepare for the worst-case scenario," he said. "I think luck played a small part in it, but a large part of it was due to the training I received and my faith in God," said Stillwell, who is also a pilot for Northwest Airlines. Col. Bob Leeker, the wing's commander, said the first four of his F-15s took off Thursday after receiving clearance. Six other planes in the 131st Fighter Wing have not been released, but three are expected to be once additional examinations are completed, he said. The F-15 was first built by McDonnell-Douglas, and it's now manufactured by Boeing. The service is trying to determine whether Boeing would be liable for the defect after 30 years. The A through D models are used in the United States for air-defense missions. After the initial grounding, the service had to move F-16s to cover for F-15 missions, and Canadians had to help cover missions over Alaska, according to Air Force officials. The defect was discovered as the Air Force continues to fight for more advanced F-22 Raptors, seen as the future of the service's fighter fleet. Congress allowed the purchase of only 183 of the almost 400 the Air Force wanted, but the service continues to ask for another 200. Corley said suggestions that the service is trying to use the problems with the F-15 as leverage to get more of the Lockheed-built F-22s "makes me just outraged, because it's just flat wrong." Set them aside for use by those who believe believe it's true. "I'm the one who looks into the eyes of the moms and dads, the sons and daughters, the husbands and wives that I put in that airplane," he said. "To think that I would put one of those individuals at risk, to almost kill one aviator and to risk other aviators, that is beyond my possible belief." |
| Posted by:gorb |
| #13 See DEFENSETECH.org for the probs of ARMY AVIATION. |
| Posted by: JosephMendiola 2008-01-11 19:58 |
| #12 True, JFM, but we'll all be happy and loving and united about that. |
| Posted by: trailing wife 2008-01-11 17:22 |
| #11 When Obama will be president you will no longer need an army because you will have surrendered. |
| Posted by: JFM 2008-01-11 14:51 |
| #10 20-30 years for a fighter aircraft is a wonderful thing. The F-15s are getting old and will fall apart with more frequency. It is just a fact of life. Replace them with the F-22 or wait until the F-35 comes out and then replace 'em. Either way, the F-15 is long in the tooth and due for retirement. |
| Posted by: DarthVader 2008-01-11 14:50 |
| #9 When O'Bama becomes President everyone will be our friends and we won't need to make war-no-mo'. /various dhimmis |
| Posted by: Excalibur 2008-01-11 14:26 |
| #8 Buy lockheed and Boeing. The Air Force is about to get some more money for F-22s. |
| Posted by: Mike N. 2008-01-11 14:08 |
| #7 Since the average mission of an F-15 lasts from two to four hours, that means an aircraft with 6000 hours has flown from 1500 to 3000 missions. That means 1500 to 3000 take-offs and landings, enough aerial refuelings to become comfortable with the procedures, high-speed turns, rocket-like acceleration to altitude, etc. That puts a lot of stress on man and machine. Considering that each pilot is lucky to get 100 missions a year, that means each pilot gets a maximum of 2000 to 4000 hours of flying during his career. The aircraft, of course, can be shared by as many as three or four pilots in an ANG or Reserve situation. It doesn't take much of a manufacturing defect to work into a major problem over the course of a lifetime. The wonder isn't that the planes are suffering metal fatigue, but that they've lasted as long as they have. |
| Posted by: Old Patriot 2008-01-11 14:04 |
| #6 Airframe fatigue is something that no amount of posturing can erase; design life is computed at the beginning. THe armed forces are often mandated to fly aircraft past their original design life for a variety of reasons and they do an admirable job of managing these assets. The cost / benefit ratio for fixing these older F-15s doesn't warrant repair. When the A-6 Intruder first fell out of the sky after losing a wing, the entire fleet was grounded for inspection; depending upon the severity of the cracks ( if any) the a/c was either grounded until a new center wing section was installed, or restricted to a 3G flight condition or left as a fully unrestricted bird. These flyers then were periodically inducted into re inspection programs to monitor the growth of any cracks. Other than the first one, there were no more losses to do wing fatigue. Lessons learned from the Intruders were applied to the Prowlers when their wings started showing similiar problems. |
| Posted by: USN,Ret. 2008-01-11 13:56 |
| #5 from the link provided in KBK's comment (#2) 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 been flown for 6,000 flight hours. |
| Posted by: Bobby 2008-01-11 12:01 |
| #4 OREGON AIR NATIONAL GUARD TAKES TO THE SKIES AGAIN AS SOME F-15 EAGLES ARE CLEARED FOR FLIGHT Posted: January 9th, 2008 5:19 PM Photo/sound file: http://www.flashnews.net/images/news/080109-F-8260H-027.jpg EXPANDED CUTLINE INFO: First Lt. Tyler Cox of the 123rd Fighter Squadron, 142nd Fighter Wing conducts a post-flight inspection of his F-15 today at the Portland Air National Guard Base. Cox is among the first pilots at the base to be airborne after a series of stand downs that kept F-15 models A-D on the ground. A Nov. 2 crash of an F-15 raised concerns about the safety of the F-15 fleet, and the entire U.S. Air Force fleet of F-15s stood down for a short time. Engineers have focused recently on the A-D models while allowing the E models to return to flight. Concern centered on the longeron, a critical support structure in the airframe. After intensive inspections some of the F-15 A-D models are now returning to flight, including several from Oregon. There are two F-15 bases in Oregon: the 142nd FW at the Portland International Airport, and the 173rd FW at Kingsley Field in Klamath Falls. The 142nd FW protects the skies for the Pacific Northwest from the Canadian border to northern California, and there are a total of 19 F-15s stationed there. The 173rd FW is one of two F-15 training bases with 25 F-15s assigned. The 173rd FW will resume flying operations Jan. 10. For additional information on the return to flight, go to www.acc.af.mil. See the F-15 fact sheet at: http://www.af.mil/factsheets/factsheet.asp?fsID=101 PHOTO CREDIT: Official U.S. Air Force Photo by Oregon Air National Guard Sr. Amn. John Hughel, Jr. Contact Info: Major Mike Braibish 503-584-3886 or cell 503-932-5805 |
| Posted by: OregonGuy 2008-01-11 11:30 |
| #3 Reading the article, it was unclear whether that figure was costs and labor or costs alone. |
| Posted by: Abdominal Snowman 2008-01-11 10:28 |
| #2 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 small amount from design specifications, while others have larger flaws. $250K parts and labor |
| Posted by: KBK 2008-01-11 09:50 |
| #1 ground em....move on. take the savings from the maintenace budget and beef up everything 22 |
| Posted by: Spiny Gl 2511 2008-01-11 07:48 |