webslave

I agree that it's one possible reading of it, but could we agree that it's not the only plausible reading of it? As I said, you can infer a connection between the two but there's nothing in that section that actually puts the two items together. If your reading of it is correct then certainly it would be a clear statement that the park knew of a safety problem related to the water level concerning the conveyor and didn't rectify it. I do note however that since the document doesn't say that it's likely that he can't back up that assertion. It's not in the risk assessment, and paragraph 128 specifically notes that the risk they were working on didn't concern the risk of collision at the top of the conveyor. If your reading that a water level sensor was to be installed for some sort of safety purpose (ie; to mitigate a risk), then what risk were they trying to mitigate? This section specifically states that he didn't feel the additional work concerned safety, which would actually support my reading of this rather than yours. It does not say that Mr Ritchie raised any danger with regard to the water level. I think that you may need to consider the very important differences here. He had identified that the speed of the logs as they traversed the drop could reach 70km/h and in the event that the water level at the bottom of that had fallen presented a hazard where one log could collide with another at a high rate of speed. This is quite distinct from TRRR where the concern was not collision at a high rate of speed. The concern at TRRR should have been capsize, entanglement and drowning, but again there's no evidence that I can see here that made the connection for them between low water level and the conveyor. This is in contrast to the Log Ride where the connection had clearly been made. I know your line of thinking here is "if he thought this up on the log ride, why not on TRRR?" but it's not borne out in the report, and on logical grounds seems implausible given the quite different risks. Abso-bloody-lutely! That's why I don't think you can just infer that they somehow had made the link between low water level and the conveyor. If there was any evidence they had made this link the report wouldn't just hint at it - it would have said so. The water level was indeed critical for the ride to function - without water they couldn't cycle the ride. Is it proven, however, that it was unsafe to operate the conveyor with anything other than a full water level? Is that even true for that matter? After all, provided you don't have a raft bottomed out at the top you can still operate the conveyor. Furthermore, one of these in-house incidences and experiences you refer to actually occurred with a full water level. Not only would that incident not have told you that the water level is safety-critical, it's actually likely to have lead you further away from that notion. The truth is that they knew or should have known that it was unsafe to operate the conveyor unless they were confident that there was nothing obstructing the transition at the top of the conveyor into the trough. What they knew or should have known is that one of the potential causes (not the only cause) for an obstruction is low water level causing a raft to bottom out in that location. Personally, it kills me that a relatively simple system such as a beam at the top of the conveyor (prior to transition) couldn't have been used to stop the conveyor any time a raft made it to the top with a deadman's run button provided to the unload operator to jog the conveyor. It's a winner for me because you can help protect against this incident, other incidents that have been like it previously, and also against incidents where you might have a person fall into the trough at unload and be at risk of being hit by a raft that enters the trough.

Exactly, that's what I'm getting at here. Some would have even been more effective than others. What's clearly apparent is; - The initial design of the ride had significant flaws. - The documentation of that construction was likely deficient or never existed. - The system for identifying safety hazards with the ride had significant flaws. - The process of maintaining the ride was flawed and/or incorrectly carried out. - The inspection regime for the ride had significant flaws. - The regulatory oversight of the ride was manifestly inadequate. - The training of ride operators was poorly documented, and generally poorly undertaken. - The overall condition of the ride plant was poor. - Modifications had been made to the ride that are unlikely to have been made, documented or assessed in a competent manner. - The method of operating the ride was an anachronism. - The process for evaluating safety incidents was very poor. C'mon buddy, you're a smart dude. We're both playing what-if here because it's the only thing we can do. You clearly asked me what-if the pump didn't stop and the water level didn't drop as if it's some sort of validation that all of this rests on a water level sensor (the original contention I'm arguing against). What I've shown you is that the same what-if is valid far beyond that one factor. I'm not saying you're wrong about a water level sensor preventing this, I'm simply saying that it's not the only thing.

This needs to be highlighted. Which is it, Skeet?

This is very true, however; Now, I may have forgotten by now if I read a part in the document where it says they considered what risk a pump failure actually caused to the operation of the ride, but I'm not sure if they ever properly made a link between the water level dropping requiring the immediate shutdown of the conveyor. I'd very much hope it was in scope too. I think we both get where each other is coming from, I guess in my case I just don't have the faith that they properly got the link between broken pump and conveyor. I mean, was that link clearly apparent to all of us before the incident? Personally, I think there's a stronger link (if I'm looking to mitigate a risk of collision/rollover caused by the conveyor) between an obstruction at the end of the conveyor and the conveyor itself. After all, for me I'd be of the opinion that since an obstruction can happen with or without a drop in the water level that you're better off (and this assumes you're only going to test for one condition) making provision to detect an obstruction rather than detect low water level. In this case? No. But that line of argument has flaws because it can be applied to more than just the water level. Would this case have still happened if; - If the water level didn't drop? No. - If the nip point didn't exist between the conveyor and the rails? No. - If they conveyor wasn't missing slats? Unlikely. - If the rails weren't there in the first place? No. - If the training/labeling on the conveyor e-stop was adequate? Probably. - If the ride hadn't already been taken out of service due to successive failures? No. - If the ride had interlocking detection for a jam/obstruction at the top of the conveyor? No. But I encourage you to look beyond this one incident and at the safety of the ride overall - could you have had a raft flip if; - If the water level didn't drop? Yes. - If the nip point didn't exist between the conveyor and the rails? No. - If they conveyor wasn't missing slats? Possibly. - If the rails weren't there in the first place? No? - If the training/labeling on the conveyor e-stop was adequate? Probably. - If the ride hadn't already been taken out of service due to successive failures? No, but this could have happened without prior failures. - If the ride had interlocking detection for a jam/obstruction at the top of the conveyor? No.

Just further to this - and perhaps somewhat in conflict with a couple of the other quotes provided here recently - these comments by Dr Frank W. Grigg, Forensic Engineering Consulting Pty Ltd strike me as interesting (my bolding); Interestingly enough, this would suggest to me that such an incident was capable of occurring without the water level dropping, which begs the question as to whether water level monitoring and action (which would have been enough in this incident) was going to be a sufficient mitigation overall. It's fair to say that shutting down the conveyor when the water level dropped in this case would have prevented this incident - but would it potentially have allowed a similar incident regardless? I guess I'm taking exception to the notion that a $10k upgrade that included a water level sensor (of which it's in dispute whether this sensor was intended to stop the conveyor) was all that was needed to here to prevent disaster. It's certainly a possible mitigation, but we know others were missed too - to focus all of the attention on a missing water level sensor is myopic.

That would be true if they considered low water level a reason to stop the conveyor, which I haven't seen any evidence of. You could well be right that they would have, but I'd have a hard time based on what I've read in this document believing that they'd have gone that far prima-facie.

Maybe I'm still missing it here (and if so I apologize), but I'm not seeing anything in paragraphs 128-130 that indicate that they considered a drop in water level had anything to do with operating the conveyor. They seemed totally focused on rollbacks and stranding of a raft at the bottom of the conveyor, rather than water level and stranding at the top of the conveyor. Taking that entire section as a whole the only time they talk about water level monitoring is in reference to efficiency rather than safety.

Are we talking about this section? Because, if so, I may not be reading that the same way you are. I don't see anything in that which tells us that in the case of a drop in water level this system would disable the conveyor. Instead, my reading of this is that if there was to be monitoring of the water level it was intended as an efficiency measure, rather than a safety measure. I can't see anything here that indicates as part of the scoping of the project that they considered it a safety measure. Yes, that supports my suggestion that water level monitoring alone was not enough here - the important part is interfacing it to the conveyor system.

Absolutely, the amount of administrative controls in-play here is quite staggering and quaint. I personally also don't see how any remotely competent person could have looked at this ride which has almost no automated safety measures in the last decade (if not longer) and said "yes, it's acceptable to me to put this much reliance into humans". I guess the problem here is that a number of people who were supposedly competent were able to justify it to themselves and those that they report to. I'm not sure I can assume that, since if you're prepared to make that assumption you would surely also have to be prepared to make the assumption that a one-button e-stop would also exist. Reading the information in this report tells me that we could have assumed nothing of these people. It's entirely plausible to me that they would have wired it in and had it flash a light at the control panel - certainly more plausible than the notion that they might have done it right. Please don't read my comments as a mitigation of Dreamworld's actions or an attempt to say that they did not fuck up. They most certainly did, and that's very clear in the report. What I'm encouraging us to do is to actually read the report and understand it rather than just doing media sound-bytes. Dreamworld didn't have one, for sure. They also never managed to engage the services of one. The regulator also failed in their duty to identify any of this, and were in my view wholly deficient too. In fact, one of the more interesting things to come out of this report for me is that I don't believe the ride operators have any significant culpability here.

Let's also bear in mind here that as far as I've read the report doesn't say that automated water level monitoring alone would have been enough to prevent this - it needed to be linked (preferably) to a non-administrative action which would have been to command the PLC to halt the conveyor. It's been a little while since I've read over that part, but I believe there's also some risks with stopping the conveyor, so these also would have had to have been mitigated. To try and dress this as a 'simple' $10k modification is erroneous.

Which is, of course, an interesting thing for him to say when his report actually references risks that had been assessed on the ride by several parties. Perhaps some obtuse wording on his part. For example; Furthermore, later in his report he goes on to state that several purportedly competent persons had looked at the ride and either failed to see the risk, or indeed considered the risk mitigated. I believe the implication here is that none of these were ultimately competent persons in the literal sense. Unfortunately this isn't solely a Dreamworld issue - these issues extended through a number of engineering firms and the OIR itself.

Actually, they knew there was a possibility the rafts could flip and decided they had done enough about it. As we now know, they had not. There's a difficult to determine but nonetheless distinct difference between knowing about a risk and believing you'd done enough to mitigate it and knowing about a risk and continuing to take it even though you know you hadn't done enough to mitigate it. That's why criminal charges are so hard to make stick with this stuff. The reality is that in almost every incident there's a case of an entity thinking they have done enough to mitigate a risk and finding out that they had not, or indeed not even having identified the risk in the first place. For all of the attention and the tragic outcome this unfortunately boils down to both (depending on who we are talking about).

That's a very strange arrangement of fire sensors.

It's easy to look back now and say "$2,500 was what they decided a human life was not even worth" but that's hyperbole. After all, it's no more meaningful than telling someone who had just killed someone in a car wreck that if they had just left 10 seconds later then it wouldn't have happened and that therefore they decided another person's life wasn't worth 10 seconds of their time. Yeah, they totally should have done it but you never know at the time that's what's riding on it. Here's a bit I found interesting;

https://www.courts.qld.gov.au/__data/assets/pdf_file/0004/641830/10545784-final-dreamworld-draft-6-for-upload.pdf

ABC News is mixing narratives:

Wuh-oh:

(because I know you guys are busy I'll try and aggregate social snippets here for people - by all means fix me up if I get it wrong)

Social media reports indicate that the brother of Cindy Low criticized Dreamworld as 'money-driven cowboys' who were more concerned with damage control. He goes on to say that DW isn't interested in paying for his counselling and would rather spend the money on marketing the park.

You can just imagine the conversation at Dreamworld HQ: "Well guys, I'd like to continue developing new experiences for guests and take proactive steps to delivery a new generation of rides and all, but it's this log ride. The log ride is why I can't do anything."