Boeing Dreamliner Safety Concerns Are Specious 402
SoyChemist writes in to note his article at Wired Science on the uproar Dan Rather has stirred up with his claim that Boeing's new 787 Dreamliner aircraft may be unsafe. "Dozens of news agencies have jumped on the bandwagon. Most of them are reporting that the carbon fiber frame may not be as sturdy as aluminum. Few have bothered to question Rather's claims that the composite materials are brittle, more likely to shatter on impact, and prone to emit poisonous chemicals when ignited. While there is a lot of weight behind the argument that composite materials are not as well-studied as aircraft aluminum, the reasoning behind the flurry of recent articles may be faulty. The very title of Rather's story, Plastic Planes, indicates a lack of grounding in science. Perhaps the greatest concern should be how well the plane will hold up to water. Because they are vulnerable to slow and steady degradation by moisture, the new materials may not last as long as aluminum. Testing them for wear and tear will be more difficult too."
TV reporters are idiots. (Score:5, Insightful)
This kind of crap is infuriating for airline companies...It doesn't take much at all to kill a whole line of planes, just the vague reputation for being unsafe. A report like this, based on a flawed understanding of Carbon vs Aluminum where the "reporter" doesn't even grasp the real issue, could do real harm.
Ahh the wonders of politics. (Score:5, Insightful)
If you go "this is unsafe!" and you were wrong, you can go well my conserns were addressed and score a political victory.
If you go "this is safe!" and it is safe. Nothing really happends no creditability loss or gained.
If you go "this is safe!" and it was found unsafe. You get fired, invistagations, rumors you were in colution with with contrators....
So if you were trying to run or stay in office what will you demmand.
Government is a failure driven buisness it is what you do wrong that hurts you and if enough people above you were fired then you finally get promoted. So Screamming and yelling and making false accuasations and make the world seem like an unbarable place to live is the best thing you can do for your job.
Composites fail differently (Score:4, Insightful)
In the End CArbon fiber isn't better or worse than a metal plane. It's just different with different things that can go wrong.
Re:And as we all know... (Score:3, Insightful)
F-16 is made of composites (Score:5, Insightful)
One concern the USAF had with the F-16 was that in the event of a crash, a cloud of electrically conductive carbon fibers would settle over the base, shorting out anything electrical. Judging by the F-16 we had burn on the taxiway at Hahn AB in 1985, that wasn't the case.
Chip H.
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Publicity (Score:2, Insightful)
Re:Typical Dan Rather (Score:4, Insightful)
True, it's not about if Dan Rather made it up or not, it's about if he did proper investigative journalism to determine if the allegations have merit out side of a disgruntled employee trying to stir up some FUD.
Or maybe Dan's just gone of the deep end [cnn.com]. Of course, should a jumbo jet fall from the sky and crash, I don't think it's going to matter it it's made of, it's going to be destroyed. Now, in situations such as crashes on the runway [www.cbc.ca], that might has some merit.
Courage.
Cheers,
Fozzy
Remember the Comet (Score:1, Insightful)
There is a learning curve for working with composites too. We are fairly far along in learning to build small (non-pressurized) aircraft, or parts of aircraft out of various composite materials, but just as in the time of the Comet, we are early in the curve for building large, pressurized aircraft. There will be "educational moments" along this curve.
Re:TV reporters are idiots. (Score:4, Insightful)
Yeah because here in the first world we didn't just have 3 plane crashing during landing due to poor maintenance. (Look up Bombadier 8Q-400).
And GP said:
This is a very big issue, if you inhale smoke from a grill you don't drop dead within seconds, if you keep doing it you will of course die from lack of oxygen. The problem they have been talking about with the carbon fiber is the smoke can contain toxins that will kill you a heck of a lot faster, making escape from the fire a moot point because you are dead trying to find the exit.
Re:TV reporters are idiots. (Score:3, Insightful)
Flexibility is defined by Young's Modulus, "E". Carbon fiber has a much higher ratio of Young's Modulus to weight, and a higher outright value of Young's Modulus, than aluminum.
Actually, yes, it is. Carbon monoxide and cyanide gas in smoke is the biggest killer in fires, including aircraft fires.
Re:unsafe, huh? (Score:1, Insightful)
Re:Trusting Dan Rather is like.... (Score:4, Insightful)
Why Dan Rather specifically? This week I watched regular tv for the first time in years. I usually just tivo stuff. The "news" I saw at the hotel is the most ignorant, consumerist, and alarmist crap I have ever seen. Rather, from what I remember years ago, seems a step above the always OJ, always Arabs-Want-to-kill-us, etc crowd.
I think the problem is that "news" in the US is just crap. Americans now prefer crap over facts. Picking on one reporter or one network isnt helping. Theyre all like this.
Re:TV reporters are idiots. (Score:5, Insightful)
There are many classifications of materials that could be interpreted as "brittle." Brittle is much too general a term to be used in engineering, so you have to be suspicious of the news article.
You can measure tensile strength, which is a measure of how much something can bend until it break. There's another measurement where you find how much something can bend until it permanently deforms, so that it won't go back to its original state. Each of these could be called "flexibility" but that doesn't tell you the whole story.
Carbon fiber when it fails may fail explosively and shatter, while a soft metal would simply deform slowly when bent far enough. This could be called "brittleness" but it really has little to do with the actual engineering problem, since if you design the carbon fiber component to high enough tolerances, you're not worried about it breaking, since the force required to break it would be so huge you'd have other, much bigger problems besides the breaking of the part. (Like, how do we get the people out of the broken plane when Godzilla is about to eat it?)
It would be easy to criticize the engineering of the plane on the news, because nobody is going to sit there for three months to check everything out -- they'll watch the demo of a small piece of carbon fiber breaking and think, "Oh my god, that could be the wing of my plane!"
"Unsafe!" (Score:2, Insightful)
CF is anisotropic material (Score:5, Insightful)
The types of CF composite that degrade faster are the ones where the resin doesn't have a UV inhibitor in it. UV degrades the resin just like it does to any plastic but with proper protection that isn't a problem. Once this was understood companies developed UV inhibitors for the resins to make them resistant to UV degradation. And you can bet the farm on a $150+ million dollar plane being adequately protected. There is no reason to think that they won't last just as long as an aluminum plane. Never mind that the resin only carries a tiny fraction of the load, in the directions the fibers aren't laid up for. Meaning the resin is mainly there to keep the material from delaminating.
Though some may not know it, but as aluminum oxidizes over time it becomes aluminum oxide which is more brittle and prone to fracture. So you face the same problem with aluminum, but it is adequately protected and hasn't been a problem for the many many years that commercial aircraft have been flying. Just like fiberglass boats, adequately protected and maintained they last a long time.
But what do I know, I'm just an aerospace engineer with some composite materials training. I should leave the science to Dan Rather.
Re:And as we all know... (Score:4, Insightful)
When it comes to the news, there are these very strict deadlines, and if you miss a key deadline by 20 minutes to fact check, you may as well just wait for the next day. And yes that's a big deal with a huge story, it could be the difference between breaking a story and being a me too response.
Using hindsight as a measure of how well an investigation was done is a practice with its sole root in ignorance. One would just assume that Nixon would be outed for the plumbers.
I think that it is amazing that people are genuinely OK with the lack of hard reporting on any of the presidents activities or the huge number of changes of course which were justified as not being changes at all, but totally against an honest mistake.
If the press had been really on their job instead of pussy footing around all the potentially huge stories without investigating them, I seriously doubt that the W fans would be complaining about this one instance rather than how the "liberal media" is out to get an honest politician.
Re:Typical Dan Rather (Score:5, Insightful)
The FAA has set some tests that must be completed by all aircraft manufacturers - and the tests have extremely simple, impossible to fake criteria. For example, the fully loaded plane must go at full throttle on the runway up to the no return line, and slam on the brakes. The plane must stop before the end of the runway, sit for 5 minutes (worst case overheating of the brakes), and then taxi to the terminal. The tires are expected to blow, and the brakes may catch on fire, but other than that no damage is allowed.
There are many tests like this. They have to pass them all. If you build a plane from glass and it passes these tests, it is just as safe as a solid steel one - it would just be a lot harder to design.
Materials do not give a plane safety. Engineering is what gives a plane safety.
Re:Remember the Comet (Score:2, Insightful)
Re:Typical Dan Rather (Score:4, Insightful)
Fired engineer: This plane is unsafe for the following reasons.
Boeing and government agencies: This plane is in complete compliance with FCC requirements, and this engineer is a racist.
Seems like it would be pretty premature to rush to some judgment on this issue without knowing:
1. The FAA's requirements for this new material, and their soundness.
2. Specific rebuttals of the claims, perhaps something more substantive than "it meets [unspecified] requirements" and vague, contextless mentions of future computer modeling.
I mean, fuck the guy if he's a racist prick. I doubt Boeing would allege something like that without a documented history, but I look forward to the release of the documentation when this goes to court. Still, I want to see some actual figures in response to his specific claims, and I don't understand why so many posters are in such a rush to judgmen...
Oh. Ah.
Re:Typical Dan Rather (Score:3, Insightful)
Actually this is extra-insightful.
The resignation of Richard M. Nixon totally changed reporting and what reporters thought they could accomplish with an investigation. Prior to the 1970s administrations were considered inviolate even if they were poor. And that inviolability was created by the first President to be impeached, Andrew Johnson [umkc.edu]. Nixon was impeached based on information provided to the House Judiciary Committee and the Senate Select Committee on Presidential Campaign Activities by the press as well as leaks from the White House.
Now the press feels that it has a special relationship with government and can actually bring governments down. Rather was a reporter during the Nixon Administration and he (and all television networks) still has strong memories of being scooped by the Washington Post, regularly and routinely. Bring scooped is a painful experience to a reporter.
Mr. Rather certainly got so excited about the possibility of releasing information that could result in a change of government that he didn't closely examine what was provided him by the CBS producer who passed off forgeries as real documents. But, to give Rather his due, he had just come back from a long trip and didn't have much time. In retrospect, anyone younger than 30 could have figured out that a typewriter would not have made the kinds of characters (in a different type size) that were visible in the document that was used to show GWB's apparent absences from the National Guard. Problem is, big media companies tend to not hire people over 30 to produce.
Additionally, big media companies no longer hire people to do research and fact-checking like they used to back when Nixon was President. They don't hire these kinds of people because the role of television news has changed from "public service" to "entertainment." That happened when news divisions were told to actually make money for the broadcasters.
Perhaps Rather was still operating under an assumption that facts were being checked. He should not have assumed that. But certainly his executive producer ought to have been more "hands-on" with this particular report.
I don't think Rather "hates" Bush. I think he, like many broadcasters and reporters, trembles with the excitement at the thought of being a central figure in the change of an administration.
Re:GPR boats suffer from "Boat Pox". (Score:3, Insightful)
Delamination of the layers, or "blistering" can be completely prevented by using an appropriate barrior coat of non-absorbing osmosis resistant epoxy.
The point is, engineers have decades of experience with laminates and epoxies that see far more moisture than a plane will in it's lifetime.
To address the next point, the poisonous chemicals during combustion are primarily a result of the expoxy that is used, not the fiber itself. Point in fact is that kevlar boats burn. It's not the kevlar doing the burning - it's the epoxy used in the lay up. Epoxy is just another polymer like the foam in the cushions, the plastic in the interior panels, or the polycarb used for lighting lenses.
A real problem with carbon fiber is fatigue. Each time carbon fiber panels are bent, the individual strands of carbon inside the laminate develop cracks. It is extremely difficult, indeed nearly impossible, to analyze what type effect these have on overall strength. This is why laminate structures using fiberglass, carbon fiber, and kevlar tend to catastrophically fail. One cannot see the tell-tale signs of impending failure like stress cracks. Once the fibers are no longer taking an appreciable amount of the load, the expoxy holding the whole thing to gether is just a hard piece of plastic that shatters.
However, the fatigue problem is one that is well understood. That is why the new military jets are using a large amount of laminates in their contrucstion. All in all, this report by a single engineer is a joke.
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Re:Typical Dan Rather (Score:1, Insightful)
However, actually bending the wings that far is an enormous task. The 777 wings deflected 24 feet before failure. It's hard enough just building an actuator that can apply 150 tons of force over a stroke of 24 feet. When you get to the point of pulling the wings all the way overhead, you'll also have to deal with a 90 degree change in your pull-direction and a stroke nearly as long as the wing itself.
This test already costs tens of millions of dollars, and pulling a wing up over the top of the plane complicates it by a factor of two or three. The cost won't be justified.
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