Is it OK to turn off O2 in Rebreather Training?

[Caveeagle]

I recently went through a week long eCCR training and find this discussion very interesting. My instructor was very clear and professional. Reviewed all drills on land ,at surface then during the dives. Pretty close to 10 hrs in the water. None of the drills were a surprise, but over the course of a typical 60m dive, he clearly meant to challenge me with the simulated issues.

I am compelled to ask: (as an instructor) How can you guarantee you will be able to turn the o2 back on if a student panics and/or bolts during the drill. What if the instructor has a failure or brain-fart? As in all things, we should plan for things to go wrong, and how to survive. It's just my opinion, but Turning off a student's o2 and waiting ~6m to see if he notices, is unacceptable risk with little value.

I have Dive buddies, who are excellent divers who dumped instructors where teaching methods were unprofessional and risky. I have also seen the "bravado" first hand where an individual was boasting about how he had f'ed with a student, all in the name of "high standards". Even one case where the "sneaky valve shut down" was observed by other divers and came over to ask "wtf" after the dives. ..they had assumed it was just a prank.

I know there are active instructors who still practice these tactics. Mask slapping, valve shut-offs, even pick pockets. I would not hire or recommend ANY of these instructors.

You know, there those who defended several live fire exercises as the only way to adequately prepare marines for combat. I think time has proven that crawling through mud with bullets flying 10" above your head is not the only way to teach you to keep your sh1t low.

 

[doctormike]

My objection is twofold 1/that in the event the drill goes pear shaped the instructor can't defend the action.

But that's the same for any training risk, right? It's possible for all sorts of things to go pear shaped - loop recovery, open water lost regulator drill, CESA, lost line drills, etc... All of these things have caused accidents.

The defense would be that ALL scuba diving involves some degree of risk, and that when we do it we assume that risk. If the criteria for a successful defense has to be that you didn't expose the student to any risk at all, then how could you do any sort of training, let alone advanced training?

All of this comes down to the question - is the risk outweighed by the benefit? I think yes, you think no. You know more about this than me, and I really appreciate the dialogue and your advice (believe it or not, I'm not being an arrogant newbie). It does seem that at least some people at high levels of experience and training DO think that the benefits outweigh the risks. I just don't think that you should imply that ANY risk is unacceptable, because then why are we doing this in the first place?

2/that you can achieve the same training outcome without the instructor being the one to shut off gas.

That's a completely different exercise, and I don't see how it's the same at all. The point of this exercise is that the student recognizes what has happened (as Superlyte mentioned upthread). If you have the student shut off the gas, that key element is eliminated.

Also, if shutting off the gas is unsafe in and of itself, why would it be less safe if the student does it? I mean, sure, if the instructor becomes incapacitated AND the student doesn't recognize hypoxia at the same time...

 

[doctormike]

well yea

didnt this just kill a guy not too long ago in a class at blue grotto?

In order to do this drill as I described it, you have to be able to see your PO2. From what I understand (see upthread), the issue with that fatality was a blackout mask that didn't allow PO2 monitoring (against standards).

 

[doctormike]

I am compelled to ask: (as an instructor) How can you guarantee you will be able to turn the o2 back on if a student panics and/or bolts during the drill.

Why would anyone panic or bolt in this drill? I mean, some people may panic and bolt at any time in CCR training (I almost did early on when I aspirated some water), but in this particular drill, the way you fail is that you don't realize what is happening. It's over LONG before you get close to hypoxia. Now a loop recovery drill? There's where you might have a panic, and no one has a problem with those...

What if the instructor has a failure or brain-fart? As in all things, we should plan for things to go wrong, and how to survive. It's just my opinion, but Turning off a student's o2 and waiting ~6m to see if he notices, is unacceptable risk with little value.

I mean, if we have to limit CCR training because the instructor might forget how to dive in the middle of the class, it's going to be pretty hard to train anyone. Yeah, the instructor could die and the student could ignore their dropping PO2 readings and then ignore the flashing red alarms at 0.4... but that's a lot of failures.

I know there are active instructors who still practice these tactics. Mask slapping, valve shut-offs, even pick pockets. I would not hire or recommend ANY of these instructors.

Difference of opinion. I would seek out these instructors. But it's OK to have a difference of opinion!

You know, there those who defended several live fire exercises as the only way to adequately prepare marines for combat. I think time has proven that crawling through mud with bullets flying 10" above your head is not the only way to teach you to keep your sh1t low.

Again, I understand your point, but I think that this is unnecessarily dramatic, and doesn't really address the actual drill. C'mon... live fire?

This is all I'm talking about. And it's a MOD 1 drill, so no deco obligation.

1) Instructor and student are swimming at depth, student is on an eCCR at high setpoint (say 1.3).
2) Instructor shuts off O2
3) Student's PO2 slowly drops over several minuts
4) If student notices the drop, they address it (try MAV, check tank valve, bailout if unfixable)
5) If they don't notice it for several minutes and the PO2 drops to, say 0.7, the instructor calmly turns on the O2, and the only way the student realizes what happened is they get a "you fail" flash card

 

[Caveeagle]

Again, I understand your point, but I think that this is unnecessarily dramatic, and doesn't really address the actual drill. C'mon... live fire?

I don't think my analogy is overly dramatic at all. Upthread an experienced instructor seems to defend the practice because he wants to feel confident in how a student react in a real situation. In real, we can only assume that it's an actual life threatening situation that the "sneak shut-off" is creating. If the student fails the test, he will likely die without immediate intervention.

And the Blue Grotto incident seems to be proof of my point. Relying on the instructor to jump in and save the day can be problematic,

No thanks.

I fully admit to being very new to CC diving. But I have always been the type of person to closely monitor my instruments and try not to introduce elements of distraction. I know how my unit reacts to low po2 levels and what signals keep me in the safe zone.

I will also point out another thing. Even if a student passes a "sneak" valve shut off drill with flying colors, that's really not a great indicator of how well he will do in the real world. You would need to repeat the test several times to reproduce the same result to have a sound statistical proof of that. So if a given student is 20% likely to notice the flashing red low po2 hud (on my system), we get lucky and 1/5 chance shows success during training! That same diver would be 80% likely to miss that signal after training.

So I think it's the overal system and situational awareness that is critical. Flying then system manually on several occasions, and post dive analysis of shearwater data to see how well I could maintain a target PO2 is key. I still have >20hrs to log before I plan to do a cave ccr crossover. I plan to spend about half of that time with po2 in low setpoint and challenging myself to monitor and control it manually.

 

[doctormike]

I don't think my analogy is overly dramatic at all. Upthread an experienced instructor seems to defend the practice because he wants to feel confident in how a student react in a real situation. In real, we can only assume that it's an actual life threatening situation that the "sneak shut-off" is creating. If the student fails the test, he will likely die without immediate intervention.

And the Blue Grotto incident seems to be proof of my point. Relying on the instructor to jump in and save the day can be problematic,

I don't know enough about the Blue Grotto incident to use that for analysis, but it does seem like it was a fundamentally different standards violation than the simple single drill that I am discussing.

I guess the way I see it is that in tech diving, we don't spend a lot of time planning for double or triple failures, because if you do that you really can't get in the water.

In order for the sneak shutoff drill to cause a fatality, you would need three failures:

1) The instructor would have to become incapacitated or separated from the student (OK, better not to do it in low vis, high current conditions)

2) The student would have to miss the dropping PO2

3) The student would have to miss the red flashing alerts at 0.4

if a given student is 20% likely to notice the flashing red low po2 hud (on my system), we get lucky and 1/5 chance shows success during training! That same diver would be 80% likely to miss that signal after training.

OK, again, we are postulating completely incompetent divers and instructors to criticize a training method. 80% likely to not only miss the PO2 drifting down, but also to miss the flashing red alerts? If we have to tailor training to that level of ability, we are better off with golf!

 

[cerich]

I don't know enough about the Blue Grotto incident to use that for analysis, but it does seem like it was a fundamentally different standards violation than the simple single drill that I am discussing.

I guess the way I see it is that in tech diving, we don't spend a lot of time planning for double or triple failures, because if you do that you really can't get in the water.

In order for the sneak shutoff drill to cause a fatality, you would need three failures:

1) The instructor would have to become incapacitated or separated from the student (OK, better not to do it in low vis, high current conditions)

2) The student would have to miss the dropping PO2

3) The student would have to miss the red flashing alerts at 0.4



OK, again, we are postulating completely incompetent divers and instructors to criticize a training method. 80% likely to not only miss the PO2 drifting down, but also to miss the flashing red alerts? If we have to tailor training to that level of ability, we are better off with golf!

from what I understand the instructor did NOT violate her agencies standards. She taught as she was taught and didn't know any better and a student died.

Now, were the agencies standards problematic? I would think so.

 

[PfcAJ]

from what I understand the instructor did NOT violate her agencies standards. She taught as she was taught and didn't know any better and a student died.

Now, were the agencies standards problematic? I would think so.

BuT aGeNcY dOeSnT mAtTeR!!

 

[doctormike]

from what I understand the instructor did NOT violate her agencies standards. She taught as she was taught and didn't know any better and a student died.

Now, were the agencies standards problematic? I would think so.

OK, I really don't know much about that event, so I probably shouldn't even respond about it. I had read that the student was using a blackout mask that didn't allow for the use of a HUD, but obviously I have no firsthand knowledge of the incident.

 

[northernone]

My ccr instructors didn't do sneak o2 shut downs. (Or other harassment drills. None of my formal certifying instructors have, but I've dove with a dozen who voluntarily do and have argued convincing as to the value of "real" training)

I would not have minded if they had included that sort of test. I'm expecting once I've completed the training to have "mastery" of the skills needed to stay alive. There's no need to be scared to demonstrate this while under expert supervision.

If I can't monitor my ppo2 with adequate vigilance to catch a "sneak" shutdown, I want both myself and my instructor to know this so we can evaluate where I'm at in my relation to rebreather diving.

Monitoring ppo2 needs to be an ability which is perfected to an acceptable risk level. If that's not demonstrably possible at a moments notice, it's likely better the student (me) needs to reevaluate.

Vigilance and understanding the serious health risks involved could be driven home by creating any number of near misses where it's "pass or die" unless the instructor is capable to intervene and save your life...

While memorable, I don't think that's the best learning environment for learning the creative problem solving needed to stay alive on a loop.

This diverges into teaching philosophy and methods, a topic I love...

Regarding court defense, I'm uninterested. I don't think it's the best teaching method.

Unless someone murders me underwater, whatever (if ever) is my cause death while diving is on me.

To test my vigilance I have asked other divers to create unexpected failures. This includes shutting down my o2 (sneak attacks are difficult but I can be lured to distraction by having me look in holes or at macro critters.) These are to create real situations I'll face without a watchful buddy and I need to be confident in my real life response.

In short, testing is different from learning.

If some of your experienced ccr instructors and thoughtful divers can help clarify where I'm straying in my thoughts, I'd appreciate the dialogue.

Cameron