"If Only..." - a scuba safety documentary that relates to aviation safety

flhrci

flhrci

Final Approach
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So, I am planning to get back into scuba diving soon after nearly 19 years off. I have been doing a lot of research online and came across a documentary that relates to aviation's safety past. The scuba diving safety "culture" and aviation safety "culture" were quite different even back in 2003 when I had to quit diving, apparently that may not have changed much. Military is also compared.

Through this tragedy, the story ends up comparing diving and aviation and how the scuba industry could learn from aviation. If you pay attention, you can see parallels all throughout the video. Anyway, I thought it interesting. Posting link for those that want to watch it.

It's sad, so be warned.

Description: "This is a documentary about the tragic and avoidable accident involving Brian Bugge, a student of a technical diving course, who died when he entered the water without his diving equipment configured correctly on 20 May 2018. The story is told through the lenses of human factors and a Just Culture."

 
Thanks - this looks interesting, I'm always down with learning more safety. I'm diving more and moving toward more advanced diving, so this is very relevant.
 
I regularly dive with a rebreather, and I knew the story. It is really hard to believe that rebreathers do not have any sort of visual alarm showing that the oxygen tank is closed. A scary number of rebreather divers died in less than 20 feet of water because they jumped with the oxygen closed, and still there is no rebreather manufacturer planning to add the feature. And in all truth, rebreather manufacturers are nothing like aircraft manufacturers. The majority have a small shop where they literally put together the rebreathers themselves, by hand. It helps a lot to have an aeronautical approach to rebreathers, but it's not the same situation.
 
I got quite a bit of SCUBA gear to sell. Happy to build a list and share to anyone interested
 
There does seem to be a parallel between scuba, especially advanced stuff, and aviation. One being that sometimes you don't know you're in trouble until you're either gone, or effectively gone because you're in an unrecoverable state. That was a sad story to watch, even knowing what was going to happen 30 seconds in.
 
Albany Tom said:
sometimes you don't know you're in trouble until you're either gone, or effectively gone because you're in an unrecoverable state.
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That's certainly possible with rebreathers, but in the case of a closed oxygen valve it would be enough to either open the valve, reachable with the right hand pretty easily, or bailout, since every rebreather diver carries at least one 'conventional' scuba cylinder as an alternate safe source of gas. Not being aware of what is happening while you get a low pO2 alarm, and often trying to go up further reducing the partial pressure of oxygen, is what becomes fatal. Divers and particularly rebreather instructors love to talk about aviation and checklists, but the reality is that very few divers understand the discipline needed to make that system work.
 
Thanks for that. I didn't know they had low po2 alarms. I did know that low o2 isn't something people can detect on their own, at least not reliably, unlike too much co2.
 
Albany Tom said:
Thanks for that. I didn't know they had low po2 alarms. I did know that low o2 isn't something people can detect on their own, at least not reliably, unlike too much co2.
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All rebreathers have multiple O2 sensors, and the reading is available on the dive computer. When the pO2 becomes low, there is a sequence of alarms, some visual, some others including vibrations and even 'buddy lights' to alert other divers of the issue. Of course sensors can fail, and they need regular maintenance. Generally rebreathers need at least an annual, like airplanes, but it is not a legal requirement, and a lot of people fiddle with sensors in very creative ways.
 
Sifossifoco said:
That's certainly possible with rebreathers, but in the case of a closed oxygen valve it would be enough to either open the valve, reachable with the right hand pretty easily, or bailout, since every rebreather diver carries at least one 'conventional' scuba cylinder as an alternate safe source of gas. Not being aware of what is happening while you get a low pO2 alarm, and often trying to go up further reducing the partial pressure of oxygen, is what becomes fatal. Divers and particularly rebreather instructors love to talk about aviation and checklists, but the reality is that very few divers understand the discipline needed to make that system work.
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I wish that had been more detail on why they he did not use the bailout (assumed.) The story skipped some details and I can only guess the diver passed out before really knowing there was an issue to troubleshoot. Dunno. Very sad and preventable.
 
flhrci said:
I wish that had been more detail on why they he did not use the bailout (assumed.) The story skipped some details and I can only guess the diver passed out before really knowing there was an issue to troubleshoot. Dunno. Very sad and preventable.
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the scrubber removes the co2 from the breathing loop. Our bodies burn oxygen and create co2 and it’s the co2 buildup in our lungs that signals us to breath. So basically he was breathing whatever oxygen was in his rebreather loop until it was used up and just went to sleep.
 
flhrci said:
I wish that had been more detail on why they he did not use the bailout (assumed.) The story skipped some details and I can only guess the diver passed out before really knowing there was an issue to troubleshoot. Dunno. Very sad and preventable.
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With the O2 cylinder completely closed, it takes a while to reach the point where the pO2 is low, because basically you keep breathing from a closed bag, the loop, with a volume of around a couple of gallons. Most rebreathers would start with a pO2 of 0.7 in the loop, after doing all the checks. If you close the cylinder at that point, you are probably entering the water with 0.55/0.6, which is hard to notice. Assuming that you drop down to 10 meters deep, without adding any oxygen, just because of the 1 ATM increase in pressure, you are going to read a pO2 of 1.1 or so. If you keep going down, the pressure will keep holding the pO2 within range for a short while. Once you finally get the alarm, around 0.35, there is little oxygen left in the loop. If you go up, which is the normal 'panic' reaction, the ambient pressure drops and the pO2 quickly goes below 0.16, which is where you lose consciousness and drown, kind of like a free diver fainting near the surface. Trust me, it's easy to react like that, I have almost done that myself at least once. The trick is that nobody really teaches you the aeronautical way. With planes, I have been told a trillion times that if the approach doesn't look perfect you go around. With rebreathers they rarely tell you that if something is wrong you bailout. There is plenty of instructors obsessing new student about 'staying on the loop', which would be the same as teaching a young pilot that he/she has to continue and fix the landing with all sort of advanced maneuvers.
 
Sifossifoco said:
With the O2 cylinder completely closed,
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Thanks for the explanation. I did not realize how/when the action of passing out happens. I may have been taught that in Nit4rox class in the early 2000's but I do not remember. I definitely have some things to relearn to be safe diving open circuit again. Probably won't ever go for a rebreather due to price.
 
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Initial Fix said:
the scrubber removes the co2 from the breathing loop. Our bodies burn oxygen and create co2 and it’s the co2 buildup in our lungs that signals us to breath. So basically he was breathing whatever oxygen was in his rebreather loop until it was used up and just went to sleep.
Click to expand...
Thank you for the explanation. I understand better now.
 
flhrci said:
Thanks for the explanation. I did not realize how/when the action of passing out happens. I may have been taught that in Nit4rox class in the early 2000's but I do not remember. I definitely have some things to relearn to be safe diving open circuit again. Probably won't ever go for a rebreather due to price.
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It was probably not taught in Nitrox because it isn't a nitrox issue. Nitrox is just breathing air with a higher mix of O2.
 
I work with rebreathers daily. Not rebreathers for scuba, but rather rebreathing circuits on anesthesia machines. I believe in 25 years of doing this work, every single machine I have used was setup as a rebreathing circuit as the default. Further, I believe every single machine had a safety design that prevented (or significantly reduced) the ability to deliver a hypoxic mixture. Really surprising that scuba rebreathing systems lack the same.
 
FORANE said:
I work with rebreathers daily. Not rebreathers for scuba, but rather rebreathing circuits on anesthesia machines. I believe in 25 years of doing this work, every single machine I have used was setup as a rebreathing circuit as the default. Further, I believe every single machine had a safety design that prevented (or significantly reduced) the ability to deliver a hypoxic mixture. Really surprising that scuba rebreathing systems lack the same.
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It's perhaps a little more complicated with scuba rebreathers, because a mix that's hypoxic at the surface might not be at depth. Also, a mix that's not hypoxic at the surface can create oxygen toxicity at depth. The O2 mix has to be adjusted continually for depth.

Early diving rebreathers could only deliver a constant mix and were only used at shallow depths to avoid these problems. Back in the mid 1980s, computer controlled rebreathers were developed to allow use at significant depth. The Wakulla Springs Project was one of the first applications. Dr. Bill Stone's company, CIS-Lunar, built rebreathers for use in the exploration of the Wakulla Springs cave system and I believe they operated in the 200'+ range. There have, of course, been lots of advancements since then.
 
BTW - the relationship between flight training and dive training is nothing new.

Back in the late 1960s, cave diving took the lives of many unskilled and ill-equipped divers. A group of experienced cave divers began to take action to prevent this and formed the National Association for Cave Diving in 1969. They began to develop standards and training programs.

One of the earliest presidents of the NACD was a gentleman named Rory Dickens. I knew Dickens fairly well, as he was my high school physics teacher and I worked as his student aid my senior year. Dickens was a former USN fighter pilot who still flew privately and was a flight instructor, as well as an open-water scuba instructor. He had a master's in physics from Purdue and in 1980 he received an award for having the top high school physics program in the US, so he was a very sharp man. He wrote a textbook on the physics of diving and I was privileged to do a little bit of the original proofreading for it.

In developing the NACD's training regimen and dive protocols, Dickens branched off his flight training. Checklists, gas planning and management, pre-dive equipment checks, gear redundancy, etc., were adapted from similar aviation disciplines.

Tragically, Dickens was murdered in the mid 1980s. A student that he was mentoring stabbed Dickens to death in Dickens' home while robbing him.
 
FORANE said:
Really surprising that scuba rebreathing systems lack the same.
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ALL rebreathers lack a warning system for a closed O2 cylinder. Crazy as it is, it seems that nobody can come up with a simple warning light or beeping sound for that situation. Checklists do help, but no doubt people tend to ignore them when rushed or doing multiple dives
 
FORANE said:
I work with rebreathers daily. Not rebreathers for scuba, but rather rebreathing circuits on anesthesia machines. I believe in 25 years of doing this work, every single machine I have used was setup as a rebreathing circuit as the default. Further, I believe every single machine had a safety design that prevented (or significantly reduced) the ability to deliver a hypoxic mixture. Really surprising that scuba rebreathing systems lack the same.
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They do, but in the accident case, the diver was the first in the water because they wanted him to take some promo video (as a student!). There are audible alarms and many systems have buddy alert lights. We know audible alarms are not reliable and to take the video, he was solo (as a student!).

I cancelled a flight because I was rushed, rusty, and had higher winds than I'm comfortable with - 3 strikes, I'm out. Then I came home and watched this video where the diver was rushed, a student, and diving in a high risk environment.

The alarm bells should have been going off in everyone's head. But I think the point of the video is that isn't part of diving culture.

It inspired me to make a recreational pre dive checklist.

Plan - Agreed
Swimsuit Pockets - Empty
Tank - Secure and strapped
Power Inflator - Connected
BCD Straps - Good condition
Releases - Functional
Dump Valves - Tight
Weights - Installed
Max Depth - Zeroed
Air Tank - On
Gauge Pressure - ~3000 psi
Mouthpiece - Air Available
Dive Computer - Working
 
bflynn said:
Plan - Agreed
Swimsuit Pockets - Empty
Tank - Secure and strapped
Power Inflator - Connected
BCD Straps - Good condition
Releases - Functional
Dump Valves - Tight
Weights - Installed
Max Depth - Zeroed
Air Tank - On
Gauge Pressure - ~3000 psi
Mouthpiece - Air Available
Dive Computer - Working
Click to expand...

Did you check your alternate? ;)
 
Power Inflator, connected, tested (quick burst of air) and IN REACH. It's too easy to connect it, put on the tank, and have it trapped under a strap or behind your head. Part of my checklist is to close my eyes and make sure I can put my hands on every regulator, tank valve, inflator, knife, and light that I am carrying

Fins, On. You don't have to dive on boats for too long before you see someone exit the boat without their fins. Often, hilarity ensues, but in current or with heavy tech gear, it can be a real problem.
 
GaryM said:
Part of my checklist is to close my eyes and make sure I can put my hands on every regulator, tank valve, ....
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I have always had issues reaching my tank valves. It's impossible for me with a backplate on and a single tank plus the adaptor. It sits too far back but I would probably never turn it off underwater anyway. The doubles I have I can reach if I finagle the backplate a little in the water although the manifold valve in the middle is a little more challenging. I found the drysuit underwear was actually limiting my flexibility for a long time. So many little things can add up though to be a big thing. I tend to abort a dive when more than none thing is off just like flying.
 
flhrci said:
I have always had issues reaching my tank valves. It's impossible for me with a backplate on and a single tank plus the adaptor. It sits too far back but I would probably never turn it off underwater anyway. The doubles I have I can reach if I finagle the backplate a little in the water although the manifold valve in the middle is a little more challenging. I found the drysuit underwear was actually limiting my flexibility for a long time.
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I'm also using a backplate and wings. My doubles mount a reg over each tank, so it's not too bad to reach the valves. With a single and the adapter, though, I have to loosen the belt and crotch strap so I can shift the tank a bit to the side. It's doable, though.


So many little things can add up though to be a big thing. I tend to abort a dive when more than none thing is off just like flying.
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Exactly. Sometimes you just have to say "Not today."

My cave instructor drilled into me the mantra, "Any diver can call off any dive at any time for any reason." I try to keep the same attitude when flying.
 
GaryM said:
Power Inflator, connected, tested (quick burst of air) and IN REACH. It's too easy to connect it, put on the tank, and have it trapped under a strap or behind your head. Part of my checklist is to close my eyes and make sure I can put my hands on every regulator, tank valve, inflator, knife, and light that I am carrying
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Yep. More than once I've had the inflator hose pop off when I didn't have the quick-connect fully seated.

I also check to make sure my regulator hoses aren't trapped under a strap or something in case I have to hand one off. I breathe the reg with the long hose (5' in open water, 7' in caves) and carry the other one under my chin, and while I would plan to hand off the long hose I'm prepared to give away either one.
 
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