Checklists in Rebreather Diving

[OTF]

It's good to get in the habit of checking O2 (valve, gauge, loop PO2) multiple times in the pre-dive process. Obviously in detail (including mav an solenoid) while running the full checklist, but also doing a quick double check of the valve and gauges when donning the unit, maybe again just as you enter the water, and a triple check as part of the S-drill underwater before or during descent. This redundancy offers multiple opportunities to catch an O2 issue if one of the checks is missed.

 

[berndo]

It's good to get in the habit of checking O2 (valve, gauge, loop PO2) multiple times in the pre-dive process. Obviously in detail (including mav an solenoid) while running the full checklist, but also doing a quick double check of the valve and gauges when donning the unit, maybe again just as you enter the water, and a triple check as part of the S-drill underwater before or during descent. This redundancy offers multiple opportunities to catch an O2 issue if one of the checks is missed.

I'd rather find out the O2 is off while sitting on a bench going through pre dive list than in the water or walking to the water.
I don't see any disadvantage in doing a pre breath but I see disadvantages in skipping it or not using a list.

 

[Germie]

The inspiration has a checklist in their computers. That sounds really great, but I have seen people who just say ok, ok, ok, ok, ok and then in the water experience that they forgot the things that are mentioned in the checklist. So the checklist in the computer is great, but divers are also human, so can be lazy.

Diving old cells is also done a lot. Oh, mines are still working is said then. And if all cells are old, you don't find the problems when calibrating most times.
So not calibrating is done quite a lot by lazy divers, but diving old cells also.

Also not analysing gas is a thing that you still see. Oxygen, why analysing, it is just oxygen. I have had a divecenter filled my oxygenbottle with pure helium. I also have had a diluent that must be a 15/55 and was an ean50. I also got ean32 in my air diluent cylinder.

Even after more than 1000 hours on ccr, I still hate it when people are talking to me when I am building my unit together. I ask them to move away for only 10 minutes. For tomorrow my unit is already ready again, only the negative test must be done.

 

[OTF]

I'd rather find out the O2 is off while sitting on a bench going through pre dive list than in the water or walking to the water.
I don't see any disadvantage in doing a pre breath but I see disadvantages in skipping it or not using a list.

I would rather catch the O2 being off while walking to the water than not at all! I never advocated skipping the pre-dive checklist, it's essential. The checklist process should itself have multiple points to catch the O2 being off, and that is the primary place to detect and solve problems. I'm advocating for ALSO getting in the habit of reaching back to check the valve, glancing at the gauges, etc. just before or while entering the water as an extra idiot check.

As for prebreathing, some people do it some don't. I don't, but my checklist thoroughly tests the O2 system in other ways. The disadvantage in doing a prebreathe is the time and discomfort spent for very little gain, unless you sit there prebreathing for 15+ minutes.

 

[rddvet]

In the case of the bugge accident, one of the recent accidents in France and a bunch of others it would have helped. They would have noticed that their O2 was closed. They were distracted which is something that can happen to most of not all people under the right circumstances.
I don't see the point in saving 3 or 4 minutes before a dive or using a pre dive checklist. Calling a safety check BS, I don't get either.

My quick breathe before hitting the water would catch that. I breathe p02 down really quickly, add 02 and watch the p02 rise, then test dil. It's my "quick version" of a prebreathe. I also watch my 02 psi on my shearwater which would also drop if my oxygen is off.

 

[RedSeaDiver2]

I dive a Poseidon Se7en, and most of the checks are automated, and it makes you do a prebreathe. On the Mk6 the automated checklists caused a lot of problems and prevented people from diving - some justified, sometimes it would just be really finicky about something, but the Se7en with the new solid state cells seems to have resolved all of that now.

 

[broncobowsher]

One of the modifications I did to the rEvo checklist was change when the O2 opens up.
Original does
Check ADV
Inflate wing

I once had an issue with those steps. Got on the loop, sucked it down, hit the ADV and got something. On the loop, stay there. Wing inflate, quick connect wasn't connected. Standing in waist deep water to avoid overheating. Weight is on my back, quick connect isn't connecting quickly, what's that flashing red? PPO2? Why is it flashing read at 0.10? Bail! Oh, on the surface. Mouthpiece out, calmly take several deep breaths. WTF? I'm still several steps away from turning the O2 on.

So my new checklist goes from
'Check ADV' directly to 'Open O2'.
Shearwater is already on, so if I had a stumble just after the Check ADV the Shearwater will be firing the solenoid adding O2. The time on the loop without functional O2 is now only a moment to check the ADV function.

Sometime you might need to revise the sequence the steps happen, not just that they are there.

 

[Germie]

But not checking valves was also a problem with one of the cave accidents last year, and this was on oc. So checking if valves are open is essential for both oc and ccr.

 

[davehicks]

But not checking valves was also a problem with one of the cave accidents last year, and this was on oc. So checking if valves are open is essential for both oc and ccr.

I dive a mCCR unit. One of my earliest lessons and checklist steps i adopted was to hold the O2 spg and watch the needle move from zero to full pressure as I fully opened the valve. No doubts about your o2 supply.

 

[Wibble]

But not checking valves was also a problem with one of the cave accidents last year, and this was on oc. So checking if valves are open is essential for both oc and ccr.

Odd how some people like to dive CCR with the O2 & dil valves at the top of the unit. Crunchtastic place to hit the roof or edges.