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NotaPublicado: 31 Jul 2012 18:30 

Registrado: 17 Nov 2009 16:33
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Ya sabéis quién lo manda... vale la pena leerlo hasta el final.
IB

----- Original Message -----
From:<<Gordon Henderson>>
To:
Sent: Friday, October 11, 2002 3:46 PM
Subject: CCR1000 fatality, Michel Guerin, Accident Report

>
>
> Posting here for David Sawatzky. (It's also been posted to the Inspiration
> list) -Gordon-
>
> -----Original Message-----
> From: Sawatzky, David
> Sent: October 4, 2002 8:54 AM
> To: inspiration@...
> Subject: CCR1000 fatality, Michel Guerin, Accident Report
>
> Fellow Inspiration Owners,
>
> I am sending this accident report to the list as there are several lessons
> we can all learn from it. Would someone please cross-post it to the
> rebreather list? I am not a member and do not wish to become a member of
> the rebreather list (too many emails already) . If this is listed twice,
> my apologies but I don't think it worked when I tried to post it
yesterday.
>
> David
>
> Dr. David Sawatzky
> Consultant in Diving / Aviation Medicine
> DRDC Toronto (formerly DCIEM)
> (Defence Research and Development Canada)
> Note new email address: 'David.Sawatzky@...-rddc.gc.ca'
>
>
>
>
> CCR1000 Fatality Report, Michel Guerin, 18 May 2002 (report written 26
Sept
> 2002)
>
>
>
> The following is my personal report of the death of my friend Michel
Guerin,
> and does not represent the official views of any organization. However, I
> have had access to the findings of the autopsy, coroner's report, police
> report, and the equipment evaluation. Michel's wife Linda has approved
the
> release of this report so that other rebreather divers can learn from this
> tragedy and hopefully prevent their own deaths.
>
>
>
> Michel was a very bright, fit, healthy, 42 year old, highly experienced
> technical diving instructor. He was meticulous in the care of his gear
and
> in his diving techniques. Michel had been diving the CCR1000 for
> approximately 6 years and had extensive experience, including many dives
> down to 330 fsw (100 meters). He was extremely knowledgeable about
> rebreathers (he also owned and dived a Drager SCR) and in the fall of 2001
> he gave a fantastic presentation on rebreathers to approximately 100
people
> at Underwater Canada in Toronto. I was to have given the talk but a work
> trip came up and I asked Michel if he would give the talk for me. At the
> last minute my work trip was cancelled and I was able to attend the talk.
> Michel did an excellent job and there is no question that he understood
> rebreathers completely.
>
>
>
> Michel was working for a bank, doing a Master's degree, as well as his
> numerous other activities. He had been very busy all winter and spring
> (normal for him) and the dive on which he died was his first dive of the
> year. We know the following facts.
>
>
>
> - On 18 May 2002 Michel and two friends went for a shore dive at
> Tobermory, Ontario. Michel invited me to dive with him that day but I was
> flying to Grand Cayman to teach two basic Inspiration CCR students and had
> to decline.
>
> - All three divers were quite experienced and all knew the dive
site
> extremely well
>
> - Michel was diving the CCR1000 while the other two divers were on
> OC twin sets
>
> - All three divers were planning shallow, simple, gear sorting out
> dives (one checking out a new twin set, the second his new digital
> underwater camera, and Michel was doing his first CCR1000 dive of the
year,
> 'just to get in the water')
>
> - The dives were planned as 'semi-solo', i.e. same place, same
time
> but fairly independent
>
> - The divers entered the water at approximately the same time
>
> - One diver was attempting to tie the dive flag to a rock on the
> bottom at 20 fsw depth and Michel swam over and tied the line off for
him.
> The divers then separated. This was two minutes into the dive (easily
seen
> on the profile downloaded from Michel's dive computer).
>
> - Friends on the surface saw a large number of bubbles from where
> Michel was diving several minutes into the dive. They could also see the
> bubbles from the other two divers a fair distance away, one to the right
and
> the other to the left of where Michel was. The bubbles continued for a
few
> minutes, Michel surfaced briefly and then went back down. The bubbles
> stopped and the people on the surface assumed all was well as they knew
that
> rebreathers were not supposed to make bubbles.
>
> - Approximately 14 minutes into the dive, the diver with the
camera
> saw Michel lying on his back in approximately 20 fsw and took some
pictures.
> He thought Michel waved and that he was goofing around. The mouthpiece
was
> out of Michel's mouth and there were bubbles coming out of the set (the
> diver with the camera was not knowledgeable about rebreathers). The diver
> then swam away, taking more pictures of the bottom.
>
> - The diver with the camera saw Michel again 24 minutes into the
> dive. He became concerned as Michel had not moved since he had seen him
> approximately 10 minutes earlier. Michel was still lying on his back,
> mouthpiece out of his mouth and now there was no gas coming out of the
> rebreather. The diver shook Michel but he was unresponsive. The diver
then
> inflated Michel's drysuit and brought him to the surface. There was no
> pulse nor respiration, CPR and resuscitation were attempted but Michel was
> dead.
>
> - Autopsy showed a small arterial gas embolism in the brain
>
> - Michel's dive computer (one data point every 20 seconds) showed
> that he stopped briefly at 20 fsw (minute 1:40 to 2:20, this is almost
> certainly when he tied off the line to the dive flag). He then descended
to
> a maximum depth of 41 fsw at minute 4:00. He slowly ascended to 30 fsw by
> minute 6:00 and stopped there for approximately 40 seconds (minute 6:00 to
> 6:40). Michel then rapidly ascended to 7 fsw (minute 7:40) and dropped
back
> down to 22 fsw (minute 8:40). He stayed at that depth for 60 seconds and
> then rapidly ascended to 2 fsw (minute 11:00, he almost certainly surfaced
> and sank before the next data point at 5 fsw 20 seconds later). Michel
then
> sank to 16 fsw (minute 11:40) and the depth remains absolutely constant
> until minute 25 when he was sent to the surface (minute 26:00) by the
other
> diver who inflated Michel's drysuit.
>
> - Equipment: CCR1000 with two onboard tanks (air and O2), drysuit
> with a bottle of gas to inflate the drysuit, BC with a second bottle of
gas
> to inflate the BC. Neither off board tank had a second stage regulator
> attached. The CCR1000 was designed to maintain a PO2 of 0.7 ata. This
set
> had almost certainly been 'adjusted' to maintain a PO2 of 1.2 ata. The
> CCR1000 also has an on/off switch to turn off the electronics (you can not
> attain a PO2 of 1.2 ata on the surface). Common practice with the CCR1000
> is to setup the rig and then either turn off the electronics, or turn off
> the O2 bottle until the diver is deep enough for the set to be able to
> maintain a PO2 of 1.2 ata. After the dive, the diluent bottle in the
> CCR1000 was empty. The O2 bottle still contained 1,750 psi of O2. The
other
> two tanks still contained gas. The attachment of the inhalation hose to
the
> mouthpiece was loose and on one of the pictures taken during the dive,
> Michel can be seen lying on his back, mouthpiece out of his mouth with the
> loop floating above him. Gas is escaping from the junction of the
> inhalation hose with the mouthpiece and NOT from the mouthpiece itself.
The
> design of the CCR1000 is such that if you are lying on your back with the
> mouthpiece out and open, diluent is continuously injected into the
breathing
> loop.
>
>
>
> Those are the facts. The following is conjecture.
>
>
>
> Michel could have turned off the electronics or the O2 bottle on the
surface
> (standard procedure) and forgotten to turn them on in the water, becoming
> hypoxic several minutes into the dive and loosing consciousness. Although
> the timing of the events is appropriate for this scenario, this
possibility
> is seen as unlikely for the following reasons. Michel was very
experienced
> to make such a simple and stupid mistake (but many highly experienced
divers
> have). This scenario requires Michel to fail to check his PO2 for the
first
> 7 minutes of the dive. As this was his first dive of the season, it would
> be more likely that he would be paying MORE attention to the PO2 than
> normal, not less. More importantly, this scenario does not fit the dive
> profile downloaded from Michel's dive computer. If he became hypoxic he
> would either have lost consciousness or realized he had a problem and
tried
> to ascend to the surface. As he ascended, the PO2 would have dropped
> further and he would have definitely passed out, sank and died. However,
he
> had his problem at 30 fsw ascended to 7 fsw and sank back to 22 fsw.
Sixty
> seconds later he again attempts to reach the surface. Waking up after you
> lose consciousness, when the PO2 in the set would be continuing to
decrease,
> is not seen as likely. The scenario is also not a good explanation for the
> large number of bubbles seen on the surface.
>
>
>
> Michel could have lost control of his buoyancy, shot to the surface,
> panicked, held his breath, embolized, lost consciousness, and sank. I
also
> believe this is highly unlikely as Michel was VERY experienced and thus
not
> likely to have died from such a basic and easily controlled problem. In
> addition, it also does not explain the two attempts to reach the surface.
> Finally, although the ascents were rapid, they were not 'out of control'.
>
>
>
> My personal belief is that something like the following happened. Michel
> was having a perfectly normal dive, the set was working fine and all was
> well. He was ascending back up the rock face and 7 minutes into the dive,
> at a depth of 30 fsw, he turned his head to look at something and the
> inhalation hose started to leak badly at the mouthpiece, letting gas out
and
> a lot of water in. Michel suddenly started getting a lot of water every
> time he tried to take a breath. He almost always dived with a stage
bottle
> but on this simple, shallow dive he did not have any other source of
> breathing gas but the loop on the CCR1000 (no OC diluent option such as is
> standard on the Inspiration nor bailout bottle).
>
>
>
> After approximately 30 seconds of trying to solve the problem on the
bottom,
> Michel decides that he has to get to the surface so he inflates his
drysuit
> and starts to ascend. He makes it to 7 fsw or less over the next minute
and
> then descends to 22 fsw. I believe Michel used his drysuit (instead of
his
> BC) for buoyancy because this is a very bad habit that most cold water
> drysuit divers have (including me until 2 years ago when I had an
'incident'
> that taught me the error of this practice). The reason drysuit divers
often
> do this is that if you have the correct amount of weight, keeping a
> comfortable amount of gas in the drysuit will also keep you neutrally
> buoyant (especially with a membrane suit). Therefore, you never use the
BC
> on a normal dive. When an emergency situation arises, you will go for the
> drysuit inflate valve on reflex (you are not even sure where the BC
inflate
> valve is as you have not used it for months/years!).
>
>
>
> The problem in this situation is that the loop on the CCR1000 was filling
> with water (because of the leak) and Michel was becoming very negative.
It
> would have taken a lot of gas in the drysuit to ascend. I suspect the
> drysuit burped gas out the neck seal, causing Michel to sink back to the
> bottom.
>
>
>
> Michel then spends 60 seconds on the bottom, probably in an only partially
> functional state before making another attempt to get to the surface.
This
> time the computer shows he made it to at least 2 fsw. I expect he briefly
> surfaced and then sank. Forty seconds later Michel was back at 16 fsw
depth
> and the profile goes flat line.
>
>
>
> On one of the two ascents, Michel embolized. I suspect he was having more
> and more difficulty as he was getting mostly water when he tried to inhale
> and that the second attempt to make the surface, in a semiconscious state,
> resulted in the embolism, loss of consciousness, and eventual drowning in
16
> fsw.
>
>
>
> Lessons learned:
>
>
>
> If Michel had a buddy, knowledgeable in CCR diving who was actually with
him
> when his set malfunctioned, he would probably have survived. A buddy who
> was not knowledgeable in CCR diving would also probably have been able to
> assist but they might not have noticed that Michel was in trouble until
too
> late, and then not known what to do.
>
>
>
> If Michel had an OC gas option that he could have switched to when his set
> malfunctioned, he would definitely have survived if the problem was the
> leak. If the problem was hypoxia, he may very well have passed out before
> he noticed the problem.
>
>
>
> If Michel had been in the habit of using his BC for buoyancy instead of
his
> drysuit, he would have arrived at and stayed on the surface on his first
> attempt. The back mounted wing style BC he was wearing and the back
mounted
> counterlung of the CCR1000 would have most likely floated him face down.
> However, there were friends and other divers on shore and he would have
> surfaced relatively close to shore so I'm sure they would have got his
head
> out of the water quite quickly and he would most likely have survived.
>
>
>
> This was an unfortunate and totally unnecessary fatality. I suspect
Michel
> was frustrated and angry just before he lost consciousness, knowing that
he
> was going to die from such a preventable situation. I hope this convinces
> all rebreather divers of the absolute necessity of having an OC option,
even
> on very shallow dives, for those rare occasions when the loop is lost.
>
>
>
> Dr. David Sawatzky
>
> Consultant in Diving and Aviation Medicine
>
> IANTD International Board of Advisors
>
> IANTD Inspiration Trimix Instructor
>
>
>

_______________________________________________________________________


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