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

[rjack321]

@rjack321 Another question I would like to ask, did the diver use a build check list? And is checking on the spacer part of the checklist?

I don't know it's not mentioned nor would it necessarily 100% prevent this misassembly error.

This may be an ignorant question or overlooked detail in the report as not a CCR diver, but is there not any warnings when the loop becomes unbreathable from lack of o2? Also, are there any sensations a diver would feel that something like this is off causing them to jump to bailout out of caution?

Not really, CO2 is insidious and is often insensible until you're in a runaway respiration scenario

 

[fullytek]

This may be an ignorant question or overlooked detail in the report as not a CCR diver, but is there not any warnings when the loop becomes unbreathable from lack of o2? Also, are there any sensations a diver would feel that something like this is off causing them to jump to bailout out of caution?

Every ccr program includes a pre-dive process after refered to as a pre jump Every prejump includes a period of breathing on the loop before getting in the water.

If the machine isn't delivering o2 or if the scrubber isn't working the problem will be obvious and if let say a diver were to hyperventilate or pass out... its better to happen on the boat or picnic table than in the water.
I see a lot of ccr divers who don't follow a pre jump checklist and fail to conduct a pre breath .

 

[pisauron]

The diluent cylinder was empty... He flashed it so much? The dive was ~15min only. Does it make sense?

Not a ccr diver.

 

[crofrog]

Every ccr program includes a pre-dive process after refered to as a pre jump Every prejump includes a period of breathing on the loop before getting in the water.

If the machine isn't delivering o2 or if the scrubber isn't working the problem will be obvious and if let say a diver were to hyperventilate or pass out... its better to happen on the boat or picnic table than in the water.
I see a lot of ccr divers who don't follow a pre jump checklist and fail to conduct a pre breath .

I’m not sure your statement about the problem being obvious is supported by the literature…

 

[rjack321]

The diluent cylinder was empty... He flashed it so much? The dive was ~15min only. Does it make sense?

Not a ccr diver.

Yes you can potentially go through A LOT of gas with a CO2 hit

 

[Kay Dee]

I’m not sure your statement about the problem being obvious is supported by the literature…

Agreed, 'that' potential problem is not always obvious with a prebreathe (but still worth doing to catch 'most' things anyway).

 

[Snusmumrik]

This may be an ignorant question or overlooked detail in the report as not a CCR diver, but is there not any warnings when the loop becomes unbreathable from lack of o2?

Hypoxic (lack of O2) loop shows no any warnings easily detectable.
Dumbness, tunnel vision (at 8% O2 ambient, personal experience), then i presume loss of consciousness.

Also, are there any sensations a diver would feel that something like this is off causing them to jump to bailout out of caution?

Too much CO2 in loop is easily detectable by high breath rate and sense of lack of air, and best way to deal with it is to bail out - that's IMHO essential basic knowledge.

 

[kensuf]

This may be an ignorant question or overlooked detail in the report as not a CCR diver, but is there not any warnings when the loop becomes unbreathable from lack of o2? Also, are there any sensations a diver would feel that something like this is off causing them to jump to bailout out of caution?

The issue wasn't a lack of O2, it was excess CO2 because the CO2 scrubber was bypassed.

CO2 is incredibly narcotic. Almost to the same extent as nitrous oxide (laughing gas). Some researchers have also played with it as an anesthetic for short duration medical procedures. Other physiological effects of CO2 include rapid respiration and heart rate. All a bad a combination underwater.

 

[fullytek]

I’m not sure your statement about the problem being obvious is supported by the literature…

It might not be supported by literature but its clearly based in fact.


This tragedy would have been prevented if a build sheet had been followed and or a pre dive checklist followed.
The diver had multiple opratuitys to catch his mistake but chose to neglect his training.

 

[crofrog]

It might not be supported by literature but its clearly based in fact.

https://www.researchgate.net/publication/273946026_The_five-minute_prebreathe_in_evaluating_carbon_dioxide_absorption_in_a_closed-circuit_rebreather_A_randomised_single-blind_study