I read in other comments on fb that he was not found in the cave, but only at 7m depth. That means the entrance. So the 5-7 minutes divetime I read somewhere are then strange.
If the accident was not medical and avoidable, we can only learn what is already written: follow a strict checklist, check your handset, check the flow of gasses before a dive, etc.
And at the start of a dive (and of course always during the dive), expecially when you dive mCCR and a hypoxic diluent: know your PO2. In every ccr course is teached: always know your PO2.
It is a sad story.
Sometimes you would be happy with an Inspiration with HUD and an irritating buzzer and auto-on if you hit the water.
But if people think about ccr, think about some options:
-The HUD, heads up display is an optional tool with leds that shows you near your eye if the PO2 is ok or not. It is optional, you can dive without. But if something happens, you see the HUD most times first. My Sidekick does not have one. I don't miss it there. But my Inspiration has one and also the other ccr's I have dived. If you are new to ccr, think about the advantages of an HUD.
-The ADV, the automatic diluent valve. This is a sort of second stage that adds gas (diluent) automatically when your counterlungs are empty if you want to breathe in when going down. Like you have to pump gas in your bcd, you have to fill your counterlungs. Not all ccr's have an ADV (like for example the Manta lungs from Megalodon), and you can also buy the Inspiration without ADV. In every course you must learn to deal with a ccr without ADV. I will not buy one without. It is such an easy tool and makes your ccr life easier.
-The MAV. Manual Add Valve. Every ccr has normally mav's to add diluent and oxygen. You must be able to maintain PO2 and lungvolume with your mav's. On my sidekick I had first only an option to add diluentgas by manually pushing the adv. I could/can switch to other diluents by connecting other gases on the adv hose. On one dive when I went down to 47m, the ADV refused to work when I hit the 30m depth and was going deeper. I had to go to OC bailout and then found out the ADV was not working and I could not fix it during that (cave)dive. So I could only add diluent gas in the lung by blowing it over the mouthpiece into the lungs. For oxygen I had a mav. Now I have both oxy and dil over a Revo switchblock. The main is still the adv that works as mav. But I have now a second option when needed. You can dive without ADV, but not without mav's. I changed my configuration easier to add offboard gases.
-CO2 sensors. That is or not available on ccr's, or most times an optional thing. Sadly there are still problems with CO2 sensors and sometimes they work well, sometimes not. The Tempstik on the Inspiration or rms from revo works very well, it is not CO2 sensor, but measures the temperature of the scrubber. I don't have an CO2 sensor on my Inspiration, but have a Tempstik. It is an good investment, but the risk is that the Tempstik shows you can dive and in reality you get CO2 problems. So here again, use your brains.
-mCCR vs eCCR. I have both. Both have pros and cons. If you dive mCCR, you must regulate your personal oxygen need by changing the intermediatepressure of the first stage. Also the size of the orifice is important. Diving over 80-100m depth can be a problem with mccr due to the orifice/leaky valve. eCCR can make lazy divers. If the unit works, it will maintain a breathable PO2. But even here, always know your PO2, check your handset often, even if you have a HUD. And every eCCR diver must know how to handle the unit in mCCR mode.
-DSV (normal ccr mouthpiece, dive surface valve) vs OCB (open circuit bailoutvalve).With an ocb you can easy switch to your diluent by holding the same mouthpiece in your mouth. It will help in case of a CO2 hit. But if you have connected it to a 3 liter bottle it will not really help you at 100m depth. Also the mouthpiece is bigger and I don't like it, too heavy when scootering. Some people have an ocb to not take offboard bailout with them on shallow dives. Oh yes, a 3 liter will bring you up in open water from 10m depth if the cylinder is full. And the next dive you start with 150 bar to 15m, it still will bring you up. And then it will be a 20m dive and just 80 bars in the diluent before the dive. Then **** hits the fan and the 3 liter cylinder will not help you anymore. So if you have an ocb and do easy shallow dives, don't become lazy and even then take enough bo with you.
If I wanted to do the 'big 8' (deep loop) in the Resselcave I would prefer my Inspiration over my Sidekick. This has to do that scootering, manually maintain the right PO2 (at Puits 4 there is a risk it becomes too high if I don't close the leaky valve for a while when I go down, then I need to open it again when I am down, of course a right choice of diluent would prevent it also), and sidemount (you loose 1 stage/bailout position) makes it more complex than just taking a backmount CCR. Of course I can do that dive also on sidemount ccr.
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