Chaos crash was caused by loose bolts

JWolg

whell the park is run by humans
humans make mistakes...deadly one's sometimes...

JWolg, it's possible, but unlikely. Virtually every fastener used in an amusement park is a hardened fastener, SAE Grade 5 or better, frequently Grade 8. Also, had the bolts in the ride not been Grade 8 bolts as specified by the manufacturer, that would probably have been mentioned in the news report. If it was wrong bolts (and we have no way of knowing) then it would have been wrong-length, not wrong-grade, in my opinion. Unfortunately, if all the bolts are broken, there is no good way to tell if they were the right length or not.

--Dave Althoff, Jr.

Credit where it's due, stoogemanmoe:

That was Ride_Op explaining about the painted lines. And that's true. That will tell you if the bolt has turned since you painted the line. It won't tell you if the torque is correct, although it should be unless there has been thermal expansion or some such.

Where were you putting the grease? On the threads, when installing the bolts? Torque values are different for lubricated bolts than for dry ones, you know.....

--Dave Althoff, Jr.

Some more news:
http://www.mlive.com/news/muchronicle/index.ssf?/xml/story.ssf/html_standard.xsl?/base/news/1013100305326910.xml
(tells more about the accident) AND
http://www.mlive.com/news/muchronicle/index.ssf?/xml/story.ssf/html_standard.xsl?/base/news/1013100306326910.xml
(tells about some new medical equipment designed for readiness in situations like the Chaos accident)

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Kara
403 Laps

It's taken 6 and a half months to determine that the bolts were loose.... Does that seem the least bit odd? And while highly unlikely, what's to say that some sick A-hole with a degree in mechanics, didn't loosen the bolts to (as Jeff would say) get his rocks off. Remember the old faithful motto of Stone Cold Steve Austin people: Don't trust anybody!

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Just when you think you have all the answers, I change the questions

It took less than a week for the industry to figure out what they think happened, for Chance to issue an updated bulletin, and for Cedar Fair to inspect their other two Chaos rides and get them back into action. CP's Chaos came back so quickly that it was absolutely certain that Cedar Fair was confident they knew what went wrong.

It's good for the industry to be able to work that fast.

It took six and a half months for the State of Michigan to release its report. For much the same reason that it is good for the company to identify and correct problems quickly, I think it's also good for the State to put off their report until ALL of the facts are in and the situation is completely analyzed. Because the State report is the one that may have legal ramifications, it is the report that may assess blame, and in many states (though apparently not Michigan) its the report that will determine what penalties are assessed and against whom. If the park's assessment of the situation turns out to be incomplete or incorrect, corrections can be made. But when this kind of a State report is wrong, Bad Things tend to happen. Better that they take six months and get it right, than that they take six days and get it completely wrong.

--Dave Althoff, Jr.

I must chime in here...
I realize that there is a lot of suspicion going on, but I feel the need to defend my guys @ MIA. Maintenance wasn't the best, we know that, but they don't deserve a lot of the stuff they're getting thrown at them. In my mind, the only reason why they aren't the greatest is because they didn't know any better. The Jourdens are nice people who ran a great small town park, but they didn't have the knowledge and experience to run any more than that. All this will soon change with CF in control.

Lets not add to what everyone at MIA is going through already...

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Kara
403 Laps

Some notes on bolts:

Bolts come in many varieties.  Far more than SAE Grades 5 and 8.  All quality bolts carry head markings that indicate the grade of the bolt.  I'm sure that the state verified the grade of the bolts prior to releasing their report.  The state probably also tested the bolts to be certain that they really meet the standard that they were marked for.  When a governemtn agency does an investigation and report on an accident, they have to rule out all other likely possibilities before issuing their report even when the cause of the accident is pretty obvious.

Painting lines on the heads of bolts is a nice extra check, but it is no substitute for a torque check.  A bolt can stretch (creep) or the configuaration of the joint can change due to dirt on the joint surfaces, thermal effects, etc. causing a bolt to loosen without turning.  In short, if the paint line moves, you know you have trouble.  If the paint line doesn't move you still need to check the torque because if might or might not be OK.

Engineering forensics can determine if the bolts were loose or if the bolts themselves were defective.  It is also possible to determine if the bolts were installed in the wrong holes.  This will show up as impact marks in the wrong places on the bolts from when things started to move.  It is also possible (and easier)  to match the fracture surfaces on the bolts to match the snapped off portion of each bolt with the portion left in the hole.

You might put a light coating of oil on the head of a bolt to prevent rust, but any mechanic who deliberately blobs grease on the heads of bolts is probably in the habit of trying to hide bad work.

RideMan said:

Prediction: Cedar Fair is going to blame maintenance procedures that were already in place when they bought the park.... they will note that it could never have happened in their other parks.

Yes... a ride falling over at another Cedar Fair park... now that could never happen!  ;)

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"When I was growing up, we were taught something called manners. You'd understand that if you weren't such an idiot." - Jack Handey

Hey Rideman, you worked your magic again, you truly are a man among boy's, literally... :)
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It's conflict that shows who a person really is!