I think you're still not getting my point. I don't disagree that that's the failure mode, it's just that my understanding is that fatigue isn't supposed to be a problem with composite parts. If you know the history of the aircraft, then you know if it's been overloaded and whether you have to inspect. Obviously, private airplanes without black boxes and so on are another story entirely. If the part hasn't been overloaded, then it's going to be ok almost all of the time, unless I'm wrong about the fatigue life. Metal airplanes NEED all that inspection because aluminum fatigues (unless you really overbuild like a DC-3).
Metal airplanes are capable of catastrophic failure, too, even with existing inspection methods. By now, if composite plane parts were all that dangerous, we'd have had more crashes from their failure. A300's are a significant fraction of the fleet, and I'm sure there are other planes with composite parts. If you're going to be totally paranoid about fatigue, then make all the airplanes out of steel! More people will die when they drive because flying will become too expensive (greater fuel consumption and less load capacity) and driving is more dangerous. Bill Conkling wrote: > > I think that with alum structures, frequent inspections uncover tell-tale > signs of ware such as marks from rubbing, dust, fatigue cracks etc. > ;There are limits as to how much wair is allowed before someting must be > done. With composites, the usuall indication of something not right, is > a airplane down in Queens and the vertical tail on the ground 4 miles > away. > > .........bc ([EMAIL PROTECTED] > > http://www.widomaker.com/~conk > Williamsburg, VA 23185 > > On Mon, 19 Nov 2001, Lincoln Ross wrote: > > > I'm aware of that, but if you don't have to inspect very often, maybe > > it's ok that it's tough to do. Or am I wrong about the fatigue life? > > > > Bill Conkling wrote: > > > > > > There is no easy way to inspect composite structures. They may show no > > > outward indication of stress, and can fail without warning. > > > > > > .........bc ([EMAIL PROTECTED] > > > > > > http://www.widomaker.com/~conk > > > Williamsburg, VA 23185 > > > > > > On Mon, 19 Nov 2001, Lincoln Ross wrote: > > > > > > > That plane was supposed to be old, wasn't it? This is the first crash I > > > > remember attributable to a failed composite component. And we don't even > > > > know that for sure yet. Probably nothing to panic about with only the > > > > one crash. The A300 was said to be pretty safe in general, and popular. > > > > > > > > It is my understanding that composites have a superior fatigue life, so > > > > maybe they only need inspection after manufacture and after suspected > > > > overloads. Or am I missing something? > > > > > > > > By the record so far, composites in jets might be said to be a safety > > > > improvement. Didn't the Brits lose 4 Comet airliners due to aluminum > > > > fatigue? Also, there's the Boeing 737 convertible, and probably a bunch > > > > of other incidents I don't remember. > > > > > > > > It would be nice if there was a dirt cheap, reliable way to inspect the > > > > composites in our models, but I'm not holding my breath. Models get > > > > overloads all the time. (For instance, in crashes that don't seem to > > > > break anything.) > > > > > > > > Paul Breed wrote: > > > > > > > > > > The Aerospace industry has seen composite construction as a big win in > > > > > terms of production flexibility and > > > > > and weight reduction. It will take time to see if the increased inspection > > > > > costs associated with > > > > > composite construction will become an issue now. > > > > > > > > > > Paul > > > > > > > > -- > > > > Lincoln Ross > > > > -- > > > > Lincoln Ross > > > > RCSE-List facilities provided by Model Airplane News. Send "subscribe" and >"unsubscribe" requests to [EMAIL PROTECTED] > > > > > > > > -- > > Lincoln Ross > > -- Lincoln Ross RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
