Rebreather NSS/CDS report from death at Peacock earlier this year.

[34109411]

CCR are complexed machine that requires a hight level of training, maintenance and understanding to operate them.

Not sure if everyone out there understands the engineering behind a specific unit the do and the don't.

It must be a terrible accident for the son and the family.

 

[steinbil]

Questions from someone with 0 experience diving a CCR:

Is it possible to avoid this outcome with any sort of reliability by bailing out early and often, at the first sign of discomfort? And in the same vein, do accidents like this one indicate anything about CCR divers willingness or hesitation to bail out?

 

[Alekseolsen]

Questions from someone with 0 experience diving a CCR:

Is it possible to avoid this outcome with any sort of reliability by bailing out early and often, at the first sign of discomfort? And in the same vein, do accidents like this one indicate anything about CCR divers willingness or hesitation to bail out?

Now I'm still a beginner diver, and even more so on a CCR, but I've heard both schools: "make it easy to "bail" to sanity breaths" in case something feels funny, and the other one "If you bail to OC you never go back on the loop".

Both options can also be reflected in how you "setup" your rig, ie. Have a BOV/necklaced bailout vs having the bailout second stage bungied on the stage, with the associated "cleanup" in case sanity breaths are taken.

The three CCR courses I've had with 3 different instructors had 3 different ways of doing things - while none of the instructors insisted for me to follow a specific way.

 

[John the Pom]

When I took a course on Safety Engineering, we were taught that administrative controls such as warning labels and checklists, while important, were completely inadequate for mitigating the most serious types of risk (i.e., those involving a real possibility of death or life-changing injury).

Human error doesn't make a system unsafe. Human error is something that will happen with 100% probability. Saying, "Someone died, but it was because they made a mistake, so we don't need to think any more about safety" is not a good approach to making systems safer.

 

[missionmtb]

Thanks to the IUCRR, whoever the Meg diver was conducting the inspection, and to all first responders and fellow divers involved. This report reads like a real robust and heroic response from the dive community in Florida. Condolences to this person's son, family, and friends for such a tragedy. 20 years of experience on a CCR is notable and really underscores the need for continued vigilance throughout our CCR diving careers.

I want to preface this by saying I'm only asking this because I think someone else in the sub mentioned the CCR model, a type that I dove for 5 years without incident. The unit's reputation I think is well known by most CCR divers and this is a surprising accident to read about from my perspective. I hope this question adds context for other CCR divers...

?--> To divers of the Meg 15 and prior (or even the Hammerhead, Defender, XCCR or other meg-like units), does the inhale tube seal engage the scrubber *before* the head/canister seal engages? My recollection from my Tiburon is that it does... I think maybe the mention of a 2" gap between the scrubber and head in the report was made to underscore how noticeably different this is physically from correct assembly. Even if the seals engaged at the same time, I imagine you could feel the absence of the centering/squaring influence of that exhale tube seal when closing the head and latching the 4 latches. I think I would also potentially feel how much more easily the head would assemble with the absence of that seal engagement (especially if I were bad about keeping them lubed...).

If I recall correctly, the difference between an 8 pound and 5.5 pound scrubber is 2", and the shorter head on the 15 and Tib is the reason you can fit a particular scrubber in one size smaller canister (mine was a 5.5 in a mini can for example) vs the 2.7 and before...

This is by no means a substitute for improvements in human factors features of any design should it be warranted and feasible, but I don't recall this being a particularly easy mistake to make or particularly difficult to notice (i.e. it would have a low score on a severity/probability/detectability score or RPN for my RA/DFMEA friends).

 

[fullytek]

Thanks to the IUCRR, whoever the Meg diver was conducting the inspection, and to all first responders and fellow divers involved. Condolences to this person's son, family, and friends for such a tragedy. 20 years of experience on a CCR is notable and really underscores the need for continued vigilance throughout our CCR diving careers.

I want to preface by saying I'm only asking this only because I think someone else in the sub mentioned the CCR model, a type that I dove for 5 years without incident. The unit's reputation I think is well known by most CCR divers and this is a surprising accident to read about from my perspective. I hope this question adds context for other CCR divers...

--> To divers of the Meg 15 and prior, does the exhale tube seal engage the scrubber *before* the lid seal engages? My recollection from my Tiburon is that it does... I think maybe the mention of a 2" gap between the scrubber and head in the report was made to underscore how dramatically different (and likely noticeable) this is from correct assembly. Even if the seals engaged at the same time, I imagine you could feel the absence of the centering/squaring influence of that exhale tube seal when closing the head and latching the 4 latches. I think I would also potentially feel how much more easily the head would assemble with the absence of that seal engagement (especially if I were bad about keeping them lubed...).

If I recall correctly, the difference between an 8 pound and 5.5 pound scrubber is 2", and the shorter head on the 15 and Tib is the reason you can fit a particular scrubber in one size smaller canister (mine was a 5.5 in a mini can for example) vs the 2.7 and before...

That's an interesting thought. So I went out and dusted off the boss lady's old meg and yes there is a feel that is present when installing the head into the can with the scrubber . The best way I can explain it is the scrubber centers the head slightly prior to feeling the restence of the large order rings sealing to the can so yes its definitely different. That said its extremely difficult to teach how to assemble something based on feel.

Yes a skilled mechanic can feel when a liner o ring fits together just right but thats not measurable.

This is again why qualty control checks are so important after assembly.

 

[fullytek]

Thanks to the IUCRR, whoever the Meg diver was conducting the inspection, and to all first responders and fellow divers involved. This reports reads like a real robust response from the dive community in Florida. Condolences to this person's son, family, and friends for such a tragedy. 20 years of experience on a CCR is notable and really underscores the need for continued vigilance throughout our CCR diving careers.

I want to preface this by saying I'm only asking this because I think someone else in the sub mentioned the CCR model, a type that I dove for 5 years without incident. The unit's reputation I think is well known by most CCR divers and this is a surprising accident to read about from my perspective. I hope this question adds context for other CCR divers...

--> To divers of the Meg 15 and prior, does the exhale tube seal engage the scrubber *before* the head/canister seal engages? My recollection from my Tiburon is that it does... I think maybe the mention of a 2" gap between the scrubber and head in the report was made to underscore how noticeably different this is physically from correct assembly. Even if the seals engaged at the same time, I imagine you could feel the absence of the centering/squaring influence of that exhale tube seal when closing the head and latching the 4 latches. I think I would also potentially feel how much more easily the head would assemble with the absence of that seal engagement (especially if I were bad about keeping them lubed...).

If I recall correctly, the difference between an 8 pound and 5.5 pound scrubber is 2", and the shorter head on the 15 and Tib is the reason you can fit a particular scrubber in one size smaller canister (mine was a 5.5 in a mini can for example) vs the 2.7 and before...

This is by no means a substitute for improvements in human factors features of any design should it be warranted and feasible, but I don't recall this being a particularly easy mistake to make or particularly difficult to notice (i.e. it would have a low score on a severity/probability/detectability score or RPN for my DFMEA friends).

 

[pisauron]

If we assume that root cause is hypercapnia, IMHO empty DIL cylinder shows that diver completely lack knowledge of hypercapnia management and bailing out procedure.

Perphas he didn't understand what the problem was as we know it now.

 

[sunnyboy]

There is another factor to consider - distraction. The situation as stated in the report is a father who has many dives on this unit and a son who just certified on that same unit.

Hypothetically if the father were being a normal father, he would perhaps tend to shepherd his son through the set-up and prep, perhaps even concentrating more on the son than his own set-up and prep. It's just possible he missed the spacer step due to the distraction of focusing on his son. He would not necessarily notice because adding the spacer is not a normal part of his typical dive with the bigger scrubber.

All told, a tragedy all around. Very, very sad.

 

[sea_ledford]

While the different sized scrubbers/spacers in this particular situation are limited to the few units that have that as an option, every single CCR that I know of has an equivalent seal that separates the exhale side from the inhale side. And as far as I've been able to determine, none of them can be detected through pre-dive checks (positive, negative or prebreathe- which as mentioned above is not particularly useful for detecting breakthrough). The only way to prevent this failure is though proper assembly, and this only way to know you did it is to correctly use a checklist.

I'm not sure if it is still true or not, but the only commonality between ALL CCR fatalities (as of a couple years ago) was a lack of written checklist used.