Error Blue hole fatality

[justinthedeeps]

In context of where the thread is going,

How, specifically, are we training the actual act of stopping someone from breathing the wrong gas?

I would argue that we are not normally training that. What we are training is a detailed, rehearsed affirmation of someone [instructor, buddy] doing everything right, every time, with the right gas. Yup, the sticker is right, every time

Thus the real act of stopping someone from a wrong gas is seldom exercised in training. How many students are expecting an instructor to make a confident mistake? Zero..

Maybe at least once during training, instructors should confidently demonstrate switching to a gas--but the wrong gas--acting like it's the right thing to do. How many students/buddies will stop it?

Shouldn't this be thrown out as a counterexample on training dives?

 

[steinbil]

Maybe at least once during training, instructors should confidently demonstrate switching to a gas--but the wrong gas--acting like it's the right thing to do. How many students/buddies will stop it?

I agree. Even just the expectation that the students might have to catch a wrong gas/MOD would ensure more of a conscious verification instead of a potentially mindless muscle memory drill. And also the act of stopping a wrong gas switch would be a good experience and hopefully instill the importance of not just looking, but seeing. Or mistakenly verifying the wrong gas in training might be one of those teachable moments the student never forgets: "oops I just helped my buddy kill himself". I would much prefer to experience that in training rather than in real life.

 

[boulderjohn]

Maybe at least once during training, instructors should confidently demonstrate switching to a gas--but the wrong gas--acting like it's the right thing to do. How many students/buddies will stop it?

It's very commonly done.

 

[justinthedeeps]

Gonna do this to my next buddy and see if they notice.

 

[divezonescuba]

What kind of config was this?

He was certified for PADI TEC Sidemount. So it could have been either backmount or sidemount.

Maybe at least once during training, instructors should confidently demonstrate switching to a gas--but the wrong gas--acting like it's the right thing to do. How many students/buddies will stop it?

This is actually a required skill in PADI TEC 50.

 

[steinbil]

He was certified for PADI TEC Sidemount. So it could have been either backmount or sidemount.

Could someone with more experience come up with a plausible explanation for why there would be a gas switch before the 21m stop on the ascent of this dive?

A 26m swimthrough at 55-60m shouldn't require hypoxic bottom gas, so unless they were going much deeper or training for/simulating deeper dives, a travel gas or bottom stage shouldn't be necessary?

And even if there was a bottom stage, it should have been used first and the switch should be to back gas, which would be much harder to mistake for a stage (unless all of the stage regs are behind the neck at the same time *shudder*)?

How are sidemount tanks distinguished from stage bottle on a sidemount tech rig? Is it possible that one of the sidemount bottles were swapped with a deco stage, and it was a simple side-to-side switch?

 

[divezonescuba]

If you are diving sidemount, you switch between your left and right tank regulators on some interval to help the gas pressures and tank weights to be similar. So on that particular dive, the probability of switching between sidemount tanks is high. This would be particularly high if they did not use a travel gas and started out with their primary gas. So, as others have stated it is remotely possible that he accidentally switched to an x50 tank accidentally at depth if he was diving sidemount.

I do not believe that he was a trimix instructor with either PADI or TDI. He is not PADI certified for TEC 65 or trimix and he is not listed as a TDI trimix or advanced trimix instructor according to TDI, nor on his own facebook page.

The original post just says technical diving class in the Blue Hole. Just because you are at the Blue Hole does not mean that you are swimming thru the arch or are going to the bottom. You can go down and take a look at the arch opening from above at 165 feet.

Just to get used to the environment and the entry protocol, I have frequently done a sequence of four dives. One to look the the arch, one to go thru the top haircut version, one thru the middle, and one to the bottom.

If they were just swiming thru the arch, a stage bottle with bottom gas would not be necessary. If they were swimming thru the arch at 175-200 feet, normally you would need to use normoxic trimix at least according to PADI training standards. We typically use x32, x100, and x18/30 for the primary gas on that dive. Although he could have stayed at 180 with x21 and not violate TDI standards. However, TDI does not list him as an extended range instructor nor did he claim to be on on his facebook page.

I have never needed to use a bottom stage on a dive there. People going to the bottom at 100 M typically use a x20/20 travel gas, x12/60 for the bottom gas, x32 or x50, and x100 for a total of 5 bottles, but no stage with bottom gas. I think that you would have to be going much deeper than 100 M to need a bottom stage. You have to get special permission from CDWS to dive deeper than 100 M.

For me once I have more than 2 deco/travel gas bottles, sidemount becomes cumbersome. If I need 2 primary gas tanks, a travel gas, and 2 deco bottles, I am going to use backmount.

So, there is a lot of unanswered questions with respect to how deep they went and what gasses they used.

 

[steinbil]

If you are diving sidemount, you switch between your left and right tank regulators on some interval to help the gas pressures and tank weights to be similar. So on that particular dive, the probability of switching between sidemount tanks is high. This would be particularly high if they did not use a travel gas and started out with their primary gas. So, as other have stated it is remotely possible that he accidentally switched to an x50 tank accidentally at depth if he was diving sidemount.

I do not believe that he was a trimix instructor with either PADI or TDI. He is not PADI certified for TEC 65 or trimix and he is not listed as a TDI trimix or advanced trimix instructor according to TDI, nor on his own facebook page.

The original post just says technical diving class in the Blue Hole. Just because you are at the Blue Hole does not mean that you are swimming thru the arch or are going to the bottom. You can go down and take a look at the arch opening from above at 165 feet.

Just to get used to the environment and the entry protocol, I have frequently done a sequence of four dives. One to look the the arch, one to go thru the top haircut version, one thru the middle, and one to the bottom.

If they were just swiming thru the arch, a stage bottle with bottom gas would not be necessary. If they were swimming thru the arch at 175-200 feet, normally you would need to use normoxic trimix at least according to PADI training standards. We typically use x32, x100, and x18/30 for the primary gas on that dive. Although he could have stayed at 180 with x21 and not violate TDI standards. However, TDI does not list him as an extended range instructor nor did he claim to be on on his facebook page.

I have never used a bottom stage on a dive there. I think that you would have to be going much deeper than 100 M to need a bottom stage. You have to get special permission from CDWS to dive deeper than 100 M.

For me once I have more than 2 deco/travel gas bottles, sidemount becomes cumbersome. If I need 2 primary gas tanks, a travel gas, and 2 deco bottles, I am going to use backmount.

So, there is a lot of unanswered questions with respect to how deep they went and what gasses they used.

Ah, I thought I had read they were going through the arch, I must have gotten something mixed up. My bad. I guess there is nothing much to go on, then.

 

[divezonescuba]

Ah, I thought I had read they were going through the arch, I must have gotten something mixed up. My bad. I guess there is nothing much to go on, then.

That is what most people do there, even those not suitably qualified. So, it is natural to have thought that.

 

[justinthedeeps]

He was certified for PADI TEC Sidemount. So it could have been either backmount or sidemount.


This is actually a required skill in PADI TEC 50.

Presumably then, drilling the act of actually stopping someone from a bad switch is particularly emphasized in sidemount tech?

We all know the Best Practice of show/read labels, trace hose, manage valves, purge reg. But seems like that didn't happen in this accident.

Is there anything else we should consider doing, in addition to this "just do the proper switch duh"?

Seems like additional procedures on the surface (and descent checks) could help. Double-check where you have attached the stages. Check that the deco stage valve is pressurized but off. Consider additional tactile or visual cues to distinguish the deco reg from others.

One twist is incorrectly install the "special reg" onto the wrong cylinder, that alone is not foolproof either.