Waterford Garda dead - County Wexford, Ireland

[uwxplorer]

What you’re attempting to do is muddy the water with totally different scenarios than what really happened in the case which this tread is about, well you’re right I won’t engage with your hypothetical arguments.

You're a tough fellow to argue with, but my argument is not to try "to muddy the water", rather to explain that very similar facts to those we are aware of so far in this accident, have been encountered in different accidents where it has been proven beyond a doubt that the rig was functioning perfectly, yet the diver failed to respond to the computer flashing red pO2 warning. So yes, we would need to know all the details of the dive to be conclusive, but without them, neither you or anyone of us can conclude definitely one way or another.

As a matter of fact, I can very well try to rationalize why a deep diver would decide to not flush his loop and save his diluent, as a way to react to a flashing red pO2 alert if:
- he was late in realizing the problem and misjudged for how long that problem was going on.
- he forgot that the Shearwater computer does not display pO2 beyond 2.5, yet of course the pO2 can go much higher.
Indeed, as mentioned several times before, a pO2 of 2.5 for a brief period of time is not necessarily going to kill you, but you need to solve that problem rapidly. One "economical" solution is to get shallower (rapidly), and this economy might be called for if for instance his diluent level was low. Flushing a loop at depth requires a lot of gas and if the diluent bottle is not full at the beginning of the dive, you may exhaust it in the process. There has been examples of this in the past.
Of course the pO2 drop will not be instantaneous, and in particular if it is not 2.5 to being with but say 4 or 5 (pure O2 at 40 m), the drop will not be rapid enough to solve the issue.
I guess giving you examples of this in the past will not help either...

At this point, we don't know and can't learn anything from this accident, except that it appears to be due to an oxtox event. My understanding was that everyone was trying to list the possible reasons leading to this situation, period. No judgment as to which one happened, but statistical guess-timates as to which ones have been observed the most frequently in the past.

 

[John the Pom]

Unfortunately the Shearwater electronics used on CCRs lack any audible (beep) or mechanical (vibrate) alert when things are in the red. The HUD is in your FOV, and should be blinking red but I wonder if it's possible at large hours to grow accustomed to it and miss it.

**SNIP**

Not only is red-green colour blindness the most common type, but colour perception changes across the visual field. It is most sensitive in the fovea, then declines towards the periphery. Red-green perception declines faster than other colour contrasts towards the periphery. A person could be red-green colour blind in their peripheral vision without being aware of it. For that reason, red/green is not a good choice for safety critical colour coding.

 

[Celt]

At this point, we don't know and can't learn anything from this accident, except that it appears to be due to an oxtox event. My understanding was that everyone was trying to list the possible reasons leading to this situation, period. No judgment as to which one happened, but statistical guess-timates as to which ones have been observed the most frequently in the past.

We don’t know because no proper independent investigation was carried out, the gear should have been stripped down and tested by experts. When and if the gear is found to have operated correctly then and only then should the user be accused of mishandling it. The diver and consumer are the ones that need to be protected not the multi million dollar industry.

 

[Turtle78]

We don’t know because no proper independent investigation was carried out, the gear should have been stripped down and tested by experts. When and if the gear is found to have operated correctly then and only then should the user be accused of mishandling it. The diver and consumer are the ones that need to be protected not the multi million dollar industry.

Does truely independent rebreather investigation even exist? Meaning by an expert who is not directly involved in the manufacturing or training or sale of rebreathers? When a rebreather accident happens, it appears that the authorities involved often have litte to no understanding of rebreathers, so a either a well respected instructor for that specific CCR or even the manufacturer are asked to examine the machine. Naturally that could lead to a conflict of interest. A dilemna, since only the manufacturer or an instructor for that specific machine are truely knowledgeable. Even though individual users may have an thorough understanding of a specific machine, authorities would not likely involve private persons in an investigation.

 

[helodriver87]

Does truely independent rebreather investigation even exist? Meaning by an expert who is not directly involved in the manufacturing or training or sale of rebreathers? When a rebreather accident happens, it appears that the authorities involved often have litte to no understanding of rebreathers, so a either a well respected instructor for that specific CCR or even the manufacturer are asked to examine the machine. Naturally that could lead to a conflict of interest. A dilemna, since only the manufacturer or an instructor for that specific machine are truely knowledgeable. Even though individual users may have an thorough understanding of a specific machine, authorities would not likely involve private persons in an investigation.

Instructors or manufacturer reps are typically the ones who look at the unit. It would be nice if we did accident analysis similar to the aviation field, but that would also require people like Mac to accept the premise that you can be a good, experienced diver, make a mistake in responding to a survivable malfunction, and still die. Pilots also seem to have a hard time accepting that people can be partially at fault when the machine breaks. It makes it much harder to get meaningful accident analysis results out into the community. I think it's an ego thing combined with a need to put all the blame on something easily avoided (don't dive a breather) instead of facing the reality that experienced people make mistakes sometimes and nobody is immune. Kind of a mental shield of sorts.

 

[cathal]

If you have information that contradicts the deeplife data you should link it.

You should verify your sources before you post. A quick search re that 'list' would have shown just how discredited that list, the author and that company is, across all diving forums.
As an example this took 2 seconds - Apocalypse rebreather

 

[KenGordon]

Unfortunately the Shearwater electronics used on CCRs lack any audible (beep) or mechanical (vibrate) alert when things are in the red. The HUD is in your FOV, and should be blinking red but I wonder if it's possible at large hours to grow accustomed to it and miss it.

No idea why Shearwater left out other signaling. Control systems that came before it like the Hammerhead would vibrate the the HUD if critical messages were on the controller. Not blaming Shearwater, their products are some of the best out there but I wonder how many deaths would have been avoided had the controllers signaled outside of display messages.

Did this diver mix the o2 tank up with the dil tank?

I think they might claim that the lack of an actual alarm is a feature. As a user you have no choice but to look at the handset or hud often enough to know your ppO2.

btw you can miss the hud being red.

do we know if this diver had bailout? How deep etc etc?

 

[cathal]

Does truely independent rebreather investigation even exist? Meaning by an expert who is not directly involved in the manufacturing or training or sale of rebreathers? When a rebreather accident happens, it appears that the authorities involved often have litte to no understanding of rebreathers, so a either a well respected instructor for that specific CCR or even the manufacturer are asked to examine the machine. Naturally that could lead to a conflict of interest. A dilemna, since only the manufacturer or an instructor for that specific machine are truely knowledgeable. Even though individual users may have an thorough understanding of a specific machine, authorities would not likely involve private persons in an investigation.

I would give the Coroner some credit. Don't forget they have conflicting loyalties in any diving fatality inquest i.e. if they rule the deceased was responsible for their demise, then the life insurance company wont pay out to the family, thereby possibly impoverishing the surviving gamily.

 

[cathal]

Rubbish, it isn’t user error if the equipment malfunctions.

Rebreathers are dangerous and that is a fact that was well known to the man that died. There’s only one explanation for what happened, the equipment malfunctioned and for whatever reason he didn’t get to use his bailout.

You seem to know for a fact that some piece of equipment failed here. Just wondering can you tell us all here then what was it that failed and where or how do you know this as a fact?

 

[cathal]

And the only reason you can make the argument referencing aircraft is there’s comprehensive investigation into aircraft accidents, there’s little or no investigation when it comes to rebreathers and no date is released or published and the reason is too many people accepting the excuse that the cause is user error. .

But there was an independent investigation into this fatality with a rebreather expert and the results were published Garda Dave Hearne who saved nine lives drowned in diving accident