Inquest into the death of Philip Andrew Gray - Death 9 February 2013

[FiddlerOnTheRoof]

Boo HOO I can voice my preference! Like I said in very plain English You guys can keep your CCRs as for myself I'll stick to my al80s and steel 100s!

You can interpret it how ever you want but if you read it carefully I am just saying CCR is not for me! No trashing involved.

---------- Post added May 6th, 2015 at 07:05 PM ----------

BTW Dreamdive I myself have owned a eCCR Megalodon Closed Circuit Rebreather for a long time and have dove CCR many times, but as a matter of preference I still prefer to dive OC.
Although I must admit the $9000+ CCR still looks good in my man cave!

---------- Post added May 6th, 2015 at 07:06 PM ----------

""You can die OC by being complacent, you can die driving a car by being complacent......complacency kills, not the type of diving.""

I couldn't agree more!

 

[hroark2112]

Please send that Meg to me in NC. I don't want you to be tempted.

I'm just trying to save you. Allow me to help!!

 

[FiddlerOnTheRoof]

Please send that Meg to me in NC. I don't want you to be tempted.

I'm just trying to save you. Allow me to help!!

The only reason I have not sold it is because it has sentimental value to me... My grandfather actually helped me buy it when I had the CCR "fever" sometime back. I do take it out for a dive once in awhile especially if I want to do a video. I also keep it in very good condition and properly maintained.

I don't need to be saved... I got over 2000 dives most of them very technical dives to places and depths many only dream of! But I tell you what... If you ever come north I promise I'll let you take it for a dive.

 

[Abdullah]

Right, both of which were crazy, but were probably caused by comfort and complacency, who knows how many times these same short cuts were taken with no ill effects. Checklists are so important in this sport, and not allowing yourself to get comfortable... ever.

So, I just realized that we may not know how many times, but we know that for two years at least one of the shortcuts was taken.

I'm not sure stretching the sensors two years past their service life is complacency. It's more like uninformed arrogance - believing he would somehow detect an impending failure before it became a hazard. No human reliably has that capability, which is why manufacturers of devices with a known service life tell you when to replace their product.

According to the report, he apparently believed a really old Teledyne to be more reliable than a new AP, which ignored the fact that product literature was telling him out-of-service-life sensors were dangerous. He apparently trusted CCR community tribal knowledge more than the engineering assessments of the people who make the things.

If you're going to dive equipment whose critical functions rely heavily on devices with a predictable failure rate, you should never exceed the predicted reliability parameters. You really don't know more than the engineers that designed the thing. Pushing the device beyond it's design limit is either arrogant or ignorant, not complacent.

 

[FiddlerOnTheRoof]

Very well said Abdullah!!! It's like changing batteries on a computer... I change mine every few dives never allow them to get half way much less low.
In my opinion, and I am a very conservative diver, I would change them every season, knowing how IMPORTANT they are.

Regardless it is very sad to hear of another diver's passing...

---------- Post added May 6th, 2015 at 09:44 PM ----------

"Oxygen sensor cells used in rebreathers are exposed to pressures of oxygen much greater than normally encountered in analyzing gas. As they age they become 'non-linear', meaning they are perfectly accurate for some conditions and very inaccurate for certain other conditions and this can have serious consequences for rebreather divers. Rebreather manufacturers recommend replacing the cells annually, long before they can become non-linear. The widely accepted absolute maximum useful lifespan of cells in rebreather applications is 18 months, with 12 months being the recommended replacement interval. pushing the useful life of an oxygen sensor is a 'risk vs. reward' decision. If you choose to use a sensor for an additional six months beyond recommendations, you saved only a few dollars and incurred an unknown but very significant risk."

 

[Dr. Lecter]

Nice to see a detailed report, though the root cause was diver error of such magnitude as to get into the ballpark of conscious indifference to survival. That's some serious current limitation and given the report showing an O2 flush before they dropped the deceased would have been aware of it.

One thing seemed off, though:

At the same time as an OC diver descends to greater depths, the ambient pressurerequires the diver to consume greater amounts of air to maintain the necessarypartial pressure of oxygen [PP02)1 to sustain life;

Yes, you consume a larger amount of gas per breath as you descend due to increasing pressure and constant volume. But no, it has nothing to do with maintaining the necessary PPO2--in fact, increasing depth leads to increased PPO2 for a given gas mix.

 

[FiddlerOnTheRoof]

"the root cause was diver error of such magnitude as to get into the ballpark of conscious indifference to survival"

I agree and unfortunately it was such a simple thing to take care and really not that expensive either considering the trade-off. Unfortunately too late for the poor lad. Hopefully others can take this very expensive lesson and LEARN FROM IT as I'm sure there are many others out there doing similar if not the same mistakes!

 

[Dr. Lecter]

"the root cause was diver error of such magnitude as to get into the ballpark of conscious indifference to survival"

I agree and unfortunately it was such a simple thing to take care and really not that expensive either considering the trade-off. Unfortunately too late for the poor lad. Hopefully others can take this very expensive lesson and LEARN FROM IT as I'm sure there are many others out there doing similar if not the same mistakes!

Re-reading the report I see the students reported performing an O2 flush/linearity check at 20', but not that the instructor did so. I'm guessing he must not have flushed, because anyone with his experience with an eCCR and those cells doing a flush would see at least two cells not getting near low set-point with a loop full of nearly 100% O2 at 20'...and realize they're going to have a real problem with their solenoid if they go deeper.

If he had, he'd probably still be alive. I understand his reluctance to do so--it's usually a waste of O2 because you've usually checked your cells recently anyway, and then you waste time and dill flushing it back down so you can drop at any kind of reasonable speed--but if you're diving 40 month-old cells (nobody should), you should be extra careful about that step.

 

[Mr.X]

Very sad and hard believe he would use cells that old. Especially as an instructor and part of the process (at least for me) was dating each cell with a start date and swapping them out on schedule. Or ahead of schedule based on linearity tests and dry voltage.s

I think the important bit here is sticking with the pre-flight and in dive protocols. And yes - CCR diving is twitchy. More to mess with, but man I love what they can do deep, or in a cave.

X

 

[ajduplessis]

..................I understand his reluctance to do so--it's usually a waste of O2 because you've usually checked your cells recently anyway, and then you waste time and dill flushing it back down so you can drop at any kind of reasonable speed--but if you're diving 40 month-old cells (nobody should), you should be extra careful about that step.

I have heard this exact some thing from various CCR divers. What I dont understand is how the CCR crowd keep japping about loads of breathing gas, however they are reluctant in doing this basic check . CCR divers will also quickly tell you how the return on investment is quickly realised by using less gas (helium & O2) than OC, but use O2 cells well outside defined specs. The same holds true to sorb, orings, batteries and maintenance to name a few.

I have yet to meet a CCR diver that sticks to all defined specification across the CCR spectrum.