Rebreather Safety

Peter Steinhoff

I find it interresting that most of the Rebreather failures seems to be attributed to human error and not to equipment failure. That is probably true but that doesn't inherently mean it's not the machine's fault or at least it's design.

When analysing human errors there are two different approaches.

1) The person approach
It's believed that the error stems from things like forgetfulness, inattention, poor motivation, carelessness, negligence or recklessness of the person. The accociated countermeasures are often retraining, blaming, changing procedures etc to directly take away the variance in human behavior.

2) The system approach
Is based on the idea that humans are...well, humans and that mistakes and errors are to be expected even in the best of worlds. The countermeasures are more based on changing the environment and the conditions under which human works instead of changing the human itself.

Reading about fighter pilots, who operates in a very taskloaded and information intense environment, it's interresting to see how their "workplace" actually is designed around them and their capacity instead of the opposite. That doesn't mean they don't need any training, but it's clearly a system approach and not a person approach.

When discussing rebreather safety I believe the focus could be shifted more towards the system and less on the individual. Instead of asking ourselves what the person did wrong and suggest solutions to how the training could be different etc we should perhaps ask ourself how the rebreather as a system could be made safer while assuming that humans will always make mistakes.

Just a thought.

Regards,
Peter Steinhoff

PS. Just to take an example (that may not be technically viable).

Let's say that we found that hypoxia and hyperoxia is the problem. That could depend on the diver not checking his PO2 and fails to react or reacts in an errant way to situations that arises. A person approach would be to introduce alarms that supposedly "can't" be ignored like vibrating HUDs, stronger audiovisual alarms etc and really expect the diver to pay attention. A system approach would be to say that we expect the possibility that divers forget to check their PO2 in very high taskloaded situations, misses alarms etc. So all RBs are equipped with a OC bailout mouthpiece that will automaticly switch to OC if loop PO2 is out of bounds or electronics not operable or switched on.

jeff h

But on the flip side this approach produces a conditioning affect in humans which breeds complacency. By making the system ultimately responsible people will indirectly learn to just rely on the buzzer (or automatic OC) thus Pavlov's dog affect.

This works only as long as the system never fails. Else what happens after 1000 hours of relying on the buzzer and the systems fails and the loop goes hypoxic?

In my opinion a balance between an alert diver and a reliable/redundant system is probably a better approach.

So my question would be how do we systematically make divers more alert and aware on every dive?

Regards,

-Jeff

rogeringebo

PM sent...................

JonnyB

Have you ever seen a Meg?
I have owned both a KISS and now a Meg, i was quite happy with the KISS though it had some drawbacks and those made me want to change to eCCR. I know exactly what Roger is talking about, and my unit was new when i bought it.
The build quality of the KISS is good, but the quality of the Meg is amazing, you cannot really appreciate it before you see it, actually you need to dive the Meg in order to really understand how it is supposed to feel when you breath underwater.

/Jonny

__________________
A quote from Crazyduck - In remembering our own Rob Davies.
"Outbound flight 777 heavy you are cleared for flight
Due west into that warm red Texas sunset
You have angels on your wings and divers memories on your six."

Rest In Peace

http://www.divetekcyprus.com
http://www.diveccr.com

graham_hk

I have a friend who does accident analysis in the oil industry. He says that the near misses and injuries are just as important as dealth for meaningful analysis. I am by no means an expert on/in accident analysis (he is) and what he says makes perfect sense to me. If it is desirable to "do" accident analysis it should be done properly.

An independent database (RBworld??) where all mal***tions, near misses etc are stored along with the deaths would be a good start. It would need to be moderated (for example, for independence - not allowing personal attacks on a manufacturer) and probably a standard reporting method needs to be set up - but I suspect these are minor and easy to solve.

Just out of interest does anybody know if OC deaths 50% can be attributed to natural causes? I would be very suspicious of the 50% figure if there is any meaningful difference.

Graham

db8us

I think it is important that we admitt that breathers are inherently more dangerous than OC diving. I know that industry and indstructors do not like this, but only with this mindset we can create an awareness IMHO.
This not about BASHING these units, it is about respecting them and be aware that they will bite you, whenever you do NOT expect this.

Also one thing i realized is that most rebreather divers, especially instructors and people with a lot of hours do not do any additional training. This could be in a workshop manner as an exchange amongst divers.
For example we require our people once a year to do that. But of course they do not have to pay, so it might have a financial apsect when done commercially.

I see the same often on race tracks. People put a lot of money in the cars but in the non-professional field they do only rarely do any driving courses.
I think we should really work on this.

Peter Steinhoff

I think an alert and aware diver is not the root cause of the problem. Think of the very experienced Rebreather divers that have died. I find it hard to believe they where all complacent, not alert and unaware.

No, I fear that the Rebreather itself might be too complex from a user perspective to handle when the sh*t hits the fan from multiple directions - some machines maybe more than others. Luckily enough that doesn't happen too often.

Regards,
Peter

Peter Steinhoff

That is actually the same with OC mix divers. To be safe I believe you have to practice emergency procedures on a regular basis no matter what system you dive.

When I was riding motorbikes they (police, bikeorg. etc) had weekend courses to get you up to speed after the winter. I think they were free. The course consisted of offroad riding, emergency braking and stuff like that.

Regards,
Peter

schford

This reads like you are trolling - you had better not be. There is no way you can draw conclusions from such a small sample. Please keep your focus on what we can do to improve safety - I expect to see headlines like this in the gutter press not on Rebreather World.

__________________
Bailout and Kit Management account for Murphy's Law

The only bad question is one you did not ask and later wish you had.

Use of Rebreather World is subject to the Rebreather World Terms & Conditions of Use

mortenkjerulff

Hi Jon.

You can not use the current number of Meg fatalities to predict anything in the future for a number of reasons, that I am not going to explain here.

If you (or others) do not trust me, you can try to do your "statistics" on f.ex the known number of inspiration deaths. E.g see if you can predict the number of deaths in the interval 2003-2005 from number of deaths in the interval 2000-2002. And if you find a way to do this, double check on other intervals like 2000-2001, 2002-2003, and 2004-2005

This is not to "attack" anyone, but rather to prevent a "mine is bigger than yours" discussion based on false assumptions.

Morten