Rob Davie's accident. (aka. BigJetDiver)

[Warren_L]

A bail out to open circuit to me would point towards a loop failure of some sort. Even with high or low ppO2, electronics failure, etc, there are options other than bailout to OC such as running semiclosed mode. Switching to OC would occur if you ran out of dil or oxygen perhaps, but there was still plenty left in each cylinder. One other possibility that has not been mentioned yet is the possibility of a caustic coctail, especially if the loop could have been compromised and if this was not the first dive on the scrubber fill. This certainly could have caused respiratory distress which could continue to manifest even after bailing out to open circuit.

 

[wedivebc]

A bail out to open circuit to me would point towards a loop failure of some sort. Even with high or low ppO2, electronics failure, etc, there are options other than bailout to OC such as running semiclosed mode. Switching to OC would occur if you ran out of dil or oxygen perhaps, but there was still plenty left in each cylinder. One other possibility that has not been mentioned yet is the possibility of a caustic coctail, especially if the loop could have been compromised and if this was not the first dive on the scrubber fill. This certainly could have caused respiratory distress which could continue to manifest even after bailing out to open circuit.

It was stated that he had mouthpiece problems on the first dive. I don't think CC was an issue. If he was unable to close the mouthpiece (DSV) properly the loop would flood gradually as the gas would expand during ascent and the unit could become increasingly less buoyant after he surfaced. Based on what I have read so far this is my best guess.

 

[Willie]

not necessarily. perhaps it took some effort to swim the unit up to the surface, and some effort to stay at the surface, which might have triggered a heart-attack, combined with perhaps the stress of the moment.

it's just speculation on my part, though, i admit

one thing against my theory is that rob was an airline pilot, and had to
have a physical every year. he would not have been allowed to fly with
a heart problem.

Had he been tested for a PFO? Seems like that manifests its problems after an abnormal exertion of energy followed by rest. Perhaps, too negative trying to ascend, drop weights struggle to get to surface, relax, pass out ...

Just a thought.

As to pilot medical testing, I believe Rob would have a physical every 6 months, with an EKG every other time. The physical itself is not exhaustive and relies heavily on history and self-reporting. Not likely that Continental would have stiffer restrictions than the norm.

Willie

 

[Kim]

I don't think CC was an issue.

I don't know enough about RBs to be sure, but wouldn't that come to light during the gas analysis? (the loop gas left WAS analyzed and found to be normal)

 

[lamont]

I thought I read that he was seen bailing out to OC. He got to the surface and he was near neutral? weighting ok? Did he surface too fast...AGE? As other have mentioned maybe some other medical problem? That would be a heck of a coincidence though to have a hear attack at the same moment as a rebreather failure. Aspirated water due to the rebreather failure?

If you start with the hypothesis it was a medical, he may have bailed to OC because the onset of symptoms made him suspect a problem with the rebreather, even though it may have been working fine.

 

[TSandM]

Caustic cocktail should have been found on autopsy. Alkali burns are pretty severe, and I doubt they would be missed.

 

[caveseeker7]

His 5ltr bailout cylinder still contained air. (the exact amount is still being confirmed but was thought to be around 150 bar, about 26.5 cu/ft)

May I ask where that info comes from?

... the weight ... specifications of the Inspiration ... maximum wing lift sold actually with the unit is 22.5kgs.

Rob's been diving modified rigs for years, and more than one configuration.
Unless you know the actual configuration he was diving you cannot know how much inherent boyancy his setup had nor if and how much weight he would have needed to dive in whatever suit he wore. Hence you can't know if he was overweighted or not. And rest asure that Rob was not diving with 14 liters in the loop.

was the autopsy cause of death drowning?

There was no autopsy I know of.

How hard is it to leave the entire system and surface?

With Rob's normal setup about the same as doubles.

Do we know if he possibly asphyxiated from water that entered through the failed mouthpiece

Unlikely since he bailed out to open circuit.

That would be a heck of a coincidence though to have a hear attack at the same moment as a rebreather failure.

Not necessarily. Rob had problems with his DSV. If he had problems breathing, especially exhaling, he may have run into CO2 problems which can contribute to heart attacks. Add that to Rob's age, his shape, that he hadn't done a lot of diving recently and a heart attack doesn't seem quite as unlikely anymore.

A bail out to open circuit to me would point towards a loop failure of some sort.

Or a scrubber failure. And that includes a perceived scrubber failure.
If Rob felt symptoms of hypercapnia he would have gone off the loop.

 

[Kim]

May I ask where that info comes from?

From drmike. He has to check his notes for the exact pressure reading but thought he remembered 150 bar. That's why I added the proviso that it's still actually information that's being checked.

 

[Kim]

With Rob's normal setup about the same as doubles.

Flooded or unflooded?

 

[caveseeker7]

Flooded or unflooded? Maybe I misunderstood the question, it's late.

Rob usually used a bp/w rather than the Inspo's BCD. So getting out of it is about the same as any bp/w, only real difference is the counterlungs. Which aren't much of an impediment doffing (or ditching) the unit, not anymore than a second stage bungied around your neck.