Du'an Guangxi China Cave Diving Accident
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OP
PfcAJ
Contributor
His backgas and 1 stage was completely empty
klausi
Contributor
While it's difficult to understand the translation, thank you for such an in-depth accident analysis/report. 170 m is a very serious depth even for highly trained tech divers, and, as others have noted, problems become serious very quickly at such depths - not much needs to go wrong. Condolences regarding the losses.
Further information from the Facebook page of the presumed Rescue team (Bulles Maniacs)
presuming also that in translation "EXPEREMENTED Means EXPERIENCED"
Unfortunately, during our expedition, a Chinese diver died during a push dive in Daxing North. The first cave diving accident in China. And the first rescue for the Bulles Maniacs team. Of course, we have done our job. No more. The cave diving community must help each other, support beyond borders, languages and diving uses. And of course, we should help government to resolve this tragic situation.
The facts...!
A team of 2 Chinese cave divers have made a push dive in Daxing north. An attempt to go deeper and further than the 162 m of Mia Pietikäinen and Pascal Bernabé. The 2 divers was support by a third diver. The most experimented diver reach the depth of 167 meters. Meanwhile, his buddy was waiting a little higher, around 162 meters. When they go back, they found the line broken at 121 meters deep. Big stress for the second diver, certainly the beginning of a too fast breathing. The most experimented diver recovered the line after 2 minutes of intense search. The started again to ascent. Around 85 meters deep, the second diver was out of gas and he asked help to his buddy. This one immediately shared his regulator. They continue to ascent. Unfortunately, the second diver was out of breath and certainly in an advanced state of panic. He started an uncontrolled and fast ascent and he abandoned his buddy. This one tried to control his friend but in vain. Despite repeated attempts to find him, he didn't. The experimented diver was in a deep state of shock. He tried to make correct decompression but he had ascent too fast and he missed several minutes of decompression. He suffered of vestibular DCI. The support diver help him to finish his decompression. The experimented diver was victim of big troubles. The support diver help him to recover, in water. They are out of the water late in the day, alive...!
Of course, Du'an government contacted us immediately. Unfortunately, we had dived at more than 80 meters and we can't dive immediately. We have to wait and to prepare equipment, rebreathers and to plan the rescue. We started early the next morning. Two divers two divers remain on the surface to manage dives and equipment. One support diver had connected the decompression and safety rope to the line. One diver go first and he discovered the body close to the main line at 51 meters deep. He had exit some tanks from the cave and connected with a orange line, the body location. A second diver has ascended the body of the dead diver. Latter, he was support by the second diver who had dive again to exit other tanks and by the first support diver. After small decompression stops, the body was brought to the surface and handed to local and medical authorities.
We found the diver with an empty twin back mounted tanks, with two empty S80 tanks and with one full of breathable gas...! We found several tanks empty in the caves and several with gas...! At different depths...! High stress and panic are always the wrong partner for cave diving and for accident management...! In conclusion. The two divers had good gas, enough tanks, not too much but enough. They had perfect equipment. The first diver was experimented and the unfortunate diver was “young experimented”.
He was married and he had two young kids. All our thoughts, our prayers and our support to his family and her friends.
presuming also that in translation "EXPEREMENTED Means EXPERIENCED"
Unfortunately, during our expedition, a Chinese diver died during a push dive in Daxing North. The first cave diving accident in China. And the first rescue for the Bulles Maniacs team. Of course, we have done our job. No more. The cave diving community must help each other, support beyond borders, languages and diving uses. And of course, we should help government to resolve this tragic situation.
The facts...!
A team of 2 Chinese cave divers have made a push dive in Daxing north. An attempt to go deeper and further than the 162 m of Mia Pietikäinen and Pascal Bernabé. The 2 divers was support by a third diver. The most experimented diver reach the depth of 167 meters. Meanwhile, his buddy was waiting a little higher, around 162 meters. When they go back, they found the line broken at 121 meters deep. Big stress for the second diver, certainly the beginning of a too fast breathing. The most experimented diver recovered the line after 2 minutes of intense search. The started again to ascent. Around 85 meters deep, the second diver was out of gas and he asked help to his buddy. This one immediately shared his regulator. They continue to ascent. Unfortunately, the second diver was out of breath and certainly in an advanced state of panic. He started an uncontrolled and fast ascent and he abandoned his buddy. This one tried to control his friend but in vain. Despite repeated attempts to find him, he didn't. The experimented diver was in a deep state of shock. He tried to make correct decompression but he had ascent too fast and he missed several minutes of decompression. He suffered of vestibular DCI. The support diver help him to finish his decompression. The experimented diver was victim of big troubles. The support diver help him to recover, in water. They are out of the water late in the day, alive...!
Of course, Du'an government contacted us immediately. Unfortunately, we had dived at more than 80 meters and we can't dive immediately. We have to wait and to prepare equipment, rebreathers and to plan the rescue. We started early the next morning. Two divers two divers remain on the surface to manage dives and equipment. One support diver had connected the decompression and safety rope to the line. One diver go first and he discovered the body close to the main line at 51 meters deep. He had exit some tanks from the cave and connected with a orange line, the body location. A second diver has ascended the body of the dead diver. Latter, he was support by the second diver who had dive again to exit other tanks and by the first support diver. After small decompression stops, the body was brought to the surface and handed to local and medical authorities.
We found the diver with an empty twin back mounted tanks, with two empty S80 tanks and with one full of breathable gas...! We found several tanks empty in the caves and several with gas...! At different depths...! High stress and panic are always the wrong partner for cave diving and for accident management...! In conclusion. The two divers had good gas, enough tanks, not too much but enough. They had perfect equipment. The first diver was experimented and the unfortunate diver was “young experimented”.
He was married and he had two young kids. All our thoughts, our prayers and our support to his family and her friends.
jethrocramp
Registered
In the original, it's not really clear what happened to the main guide line. In section 3 "ascent" it says:
Which I read as:
"After about 1 minute we began our ascent, at this point we were about 21 minutes into our dive. As I ascended my second stage bottle only had about 130bar. As we hit 130m visibility dropped to 2m."
After that there is just one sentence about the line, and from the structure it's not very clear what happened
Which I read as:
"The thing that would cause me to choke (suffocate) happened, the main guideline stopped at the junction. The guideline was gone!!!"
The first part of the phrase sounds like "And then my worst nightmare happened" and shouldn't be taken literally. So they would have passed this line on the way down, some 8-10 minutes before. Questions that jump through my head are:
The other thing that stands out is that why did both divers not notice that Wang Tao didn't switch from his back gas to his second stage at 150m? It was in their plan and it was before the stress of finding the lost line hit them. My guess is that they were ascending very fast and there was maybe only a minute between the 150m point and discovering the missing line at 130m, at which point everything became secondary to finding the guideline.
Wang Yuan and Wang Tao were using slightly different bottom gas mixtures and therefore were following different switching plans. Was this justified by the slightly different depths they planned to dive to (164m vs. 170m)? If they had both had the same plan, and were signalling to one another when they made gas switches, then it's more likely that Wang Tao wouldn't have missed his gas switch.
Which I read as:
"After about 1 minute we began our ascent, at this point we were about 21 minutes into our dive. As I ascended my second stage bottle only had about 130bar. As we hit 130m visibility dropped to 2m."
After that there is just one sentence about the line, and from the structure it's not very clear what happened
Which I read as:
"The thing that would cause me to choke (suffocate) happened, the main guideline stopped at the junction. The guideline was gone!!!"
The first part of the phrase sounds like "And then my worst nightmare happened" and shouldn't be taken literally. So they would have passed this line on the way down, some 8-10 minutes before. Questions that jump through my head are:
- What happened to make this line come free from the anchor point?
- Was it something they did on the way down?
The other thing that stands out is that why did both divers not notice that Wang Tao didn't switch from his back gas to his second stage at 150m? It was in their plan and it was before the stress of finding the lost line hit them. My guess is that they were ascending very fast and there was maybe only a minute between the 150m point and discovering the missing line at 130m, at which point everything became secondary to finding the guideline.
Wang Yuan and Wang Tao were using slightly different bottom gas mixtures and therefore were following different switching plans. Was this justified by the slightly different depths they planned to dive to (164m vs. 170m)? If they had both had the same plan, and were signalling to one another when they made gas switches, then it's more likely that Wang Tao wouldn't have missed his gas switch.
OP
PfcAJ
Contributor
The difference in bottom gases is pretty insignificant. 2 percentage points of oxygen is hardly worth anything.
but 2 percent of oxygen affects your deco in that depths really fast. Calculate a dive to 110m with a 10 or 11% oxygen and bottomtime of a 15-20 minutes. You will see about 10 minutes deco difference if others are same. 164 or 170m is in that depths really a difference. We are not talking about a 'deep dive' in recreational limits like 24 or 30m on a single tank.
Ok, switches could be done by both divers on same place.
At such depths, mentally you must be able to do that dive too. All feels to go slow. I have been over 120m and really, even with no narced feelings, totally clear in head, it feels that you swim slowly.
If you loose a line in that depths with 2m viz, stress is really coming. 1 minute searching means a 15 minutes more deco. Do you have gas for that? 2 minutes searching half an hour more deco. And then thermal stress at shallower stops?
Ok, switches could be done by both divers on same place.
At such depths, mentally you must be able to do that dive too. All feels to go slow. I have been over 120m and really, even with no narced feelings, totally clear in head, it feels that you swim slowly.
If you loose a line in that depths with 2m viz, stress is really coming. 1 minute searching means a 15 minutes more deco. Do you have gas for that? 2 minutes searching half an hour more deco. And then thermal stress at shallower stops?
OP
PfcAJ
Contributor
Your analyzer isn't even that accurate. The difference is academic.
Back to the OP.
I found the translation difficult to fully understand but from what I think was being said, I would have to say that the first domino stone was tipped over on the surface well before the dive ever started.
The divers seemed to be fairly well trained on the surface of it and had some experience but if it seems like this dive included a *huge* over-reaching and a type of experimentation that would not be consistent with any tech agency's philosophy with respect to thorough planning, build up of sufficient experience (progressive approach) and risk avoidance, in particular with the over-reaching nature of this dive.
I'd like to add a possible scenario, which is speculative on my part. What I *think* may have happened is that they had spent some time with Pascal Burnabe prior to the dive and were inspired by that to try something out of their reach. I think this because they appear to mention talking to him in the accident report in particular with respect to planning the deco schedule. I have a sense of how that feels because I've met Mark Ellyatt and spoken to him at length and you *do* tend to come away from these encounters feeling like you could (or at least want to) do it too.... but you can't. These guys are on a different planet entirely but hanging around with them can make you feel like something rubbed off on you.
I believe this may have played a role here too.
In other words I think it's possible that this accident was caused in part because they were inspired by an encounter with a famous "heavy weight" to try something entirely expermental (to them) and as a result were operating well outside the envelope of their own training and experience.
R..
I found the translation difficult to fully understand but from what I think was being said, I would have to say that the first domino stone was tipped over on the surface well before the dive ever started.
The divers seemed to be fairly well trained on the surface of it and had some experience but if it seems like this dive included a *huge* over-reaching and a type of experimentation that would not be consistent with any tech agency's philosophy with respect to thorough planning, build up of sufficient experience (progressive approach) and risk avoidance, in particular with the over-reaching nature of this dive.
I'd like to add a possible scenario, which is speculative on my part. What I *think* may have happened is that they had spent some time with Pascal Burnabe prior to the dive and were inspired by that to try something out of their reach. I think this because they appear to mention talking to him in the accident report in particular with respect to planning the deco schedule. I have a sense of how that feels because I've met Mark Ellyatt and spoken to him at length and you *do* tend to come away from these encounters feeling like you could (or at least want to) do it too.... but you can't. These guys are on a different planet entirely but hanging around with them can make you feel like something rubbed off on you.
I believe this may have played a role here too.
In other words I think it's possible that this accident was caused in part because they were inspired by an encounter with a famous "heavy weight" to try something entirely expermental (to them) and as a result were operating well outside the envelope of their own training and experience.
R..
Hi
The mention of meeting some people who did things you want to do is a good point but it seems to me that this accident is "just" the result of a panic which could happen to anybody at anytime.
Yes training and practice are there to tell us how to respond but in real situations so many factors are involved that I believe the same person in the same situation would have different reactions according to some indeterminate factors which would trigger a different reaction. Indeed luck is also part of the equation
Jle
The mention of meeting some people who did things you want to do is a good point but it seems to me that this accident is "just" the result of a panic which could happen to anybody at anytime.
Yes training and practice are there to tell us how to respond but in real situations so many factors are involved that I believe the same person in the same situation would have different reactions according to some indeterminate factors which would trigger a different reaction. Indeed luck is also part of the equation
Jle
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