Accident in Finland

[Robert Månsson]

From the JJ-CCR manual:

Switching on the controller
In order that the controller is able to accept the actual ambient pressure (this is used for the altitude
adjustment) it should be switched on briefly whilst at the surface, prior to the dive. If this does not take
place and the controller switches itself on automatically (water contact or pressure) then it is unable to
determine the current altitude. In this case the controller will assume sea level.

Setpoint -> .19
This menu item is only displayed in surface mode. It enables a switching
off of the solenoid whilst the circuit is in air. This prevents the solenoid
from being permanently active. The function is mainly used during
a firmware upgrade or when uploading dives to the PC.
Switching to the normal setpoint takes place in the ”Switch SP” menu.
The controller switches automatically to the low setpoint if a dive is to be
started with the setting .19.

 

[erikradstrom]

O.K. yours does, but it is not standard for JJ Controllers.

So, I understand JJ Controllers do not have wet contacts and/or auto-turn ON feature.

I was trying to understand if JJ Controllers have auto-turn OFF features (or they stay ON forever unless Turned-Off manually by pushing buttons).

Mine is the same as on the JJ so they also have them.

 

[Robert Månsson]

Ok - atleast two who could manage to find the manual. :agree:

 

[gianaameri]

From the JJ-CCR manual:

Switching on the controller
In order that the controller is able to accept the actual ambient pressure (this is used for the altitude
adjustment) it should be switched on briefly whilst at the surface, prior to the dive. If this does not take
place and the controller switches itself on automatically (water contact or pressure) then it is unable to
determine the current altitude. In this case the controller will assume sea level.

Setpoint -> .19
This menu item is only displayed in surface mode. It enables a switching
off of the solenoid whilst the circuit is in air. This prevents the solenoid
from being permanently active. The function is mainly used during
a firmware upgrade or when uploading dives to the PC.
Switching to the normal setpoint takes place in the ***8221;Switch SP***8221; menu.
The controller switches automatically to the low setpoint if a dive is to be
started with the setting .19.

So, we can rule out the diver being in the water with the JJ Controller OFF (absent a malfunction).

The ADV leaking or the O2 turned Off or the Setpoint too low (.19) appear the primary suspects.

Sent from my HTC Desire C using Tapatalk 2

 

[Bruce Partridge]

From the JJ-CCR manual:

Switching on the controller
In order that the controller is able to accept the actual ambient pressure (this is used for the altitude
adjustment) it should be switched on briefly whilst at the surface, prior to the dive. If this does not take
place and the controller switches itself on automatically (water contact or pressure) then it is unable to
determine the current altitude. In this case the controller will assume sea level.

Setpoint -> .19
This menu item is only displayed in surface mode. It enables a switching
off of the solenoid whilst the circuit is in air. This prevents the solenoid
from being permanently active. The function is mainly used during
a firmware upgrade or when uploading dives to the PC.
Switching to the normal setpoint takes place in the ”Switch SP” menu.
The controller switches automatically to the low setpoint if a dive is to be
started with the setting .19.

We just got back from the OzTek and BTS shows late last night.

Thanks for correcting the wrong information Robert.

Shearwater CONTROLLERS have always had wet contacts since the GF. They were disabled on Pursuit and newer COMPUTERS to mitigate the risk of consuming the batteries on the surface.

Controllers and computers will shut off if they do not get wet or sense pressure. This is to mitigate the risk of draining the batteries or oxygen tank if the controller is inadvertently left on.

Automatic turn on will be activated by either the wet contacts or the depth sensors if the user does not activate the computer.

This functionality is for the convenience of the diver, and is in no way meant to be a complete solution. If the user does not confirm that their life support system is functioning before starting the dive, there is no system on the market that can mitigate all possible failures. One example would be an empty oxygen tank.

Technical rebreathers require specific operational behaviors to be used safely. This is true now of all rebreathers on the market and will remain true for the foreseeable future.

Bruce

 

[Dr.Alex]

Bit tricky on a Sentinel (and possibly Poseidon Mk6) as the surface set-point is 0.4. It only raises to 0.7 once below the "splash" zone.

FYI - I was led to understand that pre-breathing on a lower set-point meant you where more likely to feel any CO2 effects (that's masked by higher set-points)

Not sure I get why a PPO2 higher than 0.4 is tricky on a Sentinel. Why would you not be able to raise your PPO2 to higher than 0.4 on a Sentinel using the manual O2 add before you jump in? The important thing is PPO2 not set point.

The procedure of having higher PPO2 in the loop (0.7-1) at water entry has nothing to do with what level the solenoid brings the system, but to what level the diver brings the system.
I would caution against over-reliying on the set point and solenoid and instead fly the unit much more manually especially early in the dive. This habit will also force frequent handset or HUD checks than relying on the unit to control it automatically while connecting bottles etc. Have set point at 0.7 and bring it up to near 1.0.
Also, I tend to enter the water and add bailout bottles while using the BOV in OC mode on the surface. I only switch to CC once done and ready and checking handsets and HUD. Those 10-15 breaths on the surface seem to use not BO gas worth worrying about in my experience.
Best,
Alex

 

[Dave Sutton]

0.19 is "OFF" on a Shearwater. It's designed for use when servicing the rig with controller on and air in the loop, or turning the rig off deliberately for any reason.

It is no more a dive mode than "OFF" would be.

Dave

.

 

[gianaameri]

0.19 is "OFF" on a Shearwater. It's designed for use when servicing the rig with controller on and air in the loop, or turning the rig off deliberately for any reason.

It is no more a dive mode than "OFF" would be.

Dave

.

Nope.

OFF is a blank screen.

Anything other than a blank screen is not OFF. It is ON.

Of course a Setpoint of 0.19 is not safe and should not be dived (but the Human Factor if given an opportunity to make a mistake, it will make one, eventually...).

To remove the risk of Human Error you got to make ON = SAFE and you have to make it very obvious when OFF is OFF.

You know airplanes when they arm and disarm the Emergency Exit. It has to be easy and clear when it is ON and when it is OFF (or someone will blow-up the evacuation slide eventually at the Gate by mistake).

 

[nickb]

But it's better than starting a dive on 0.19 that the JJ/Shearwater appears to let you do.

Not so. As soon as the JJ/SW goes into dive mode, it changes the setpoint to the low value (default 0.7).

Why are we having this debate about what might or might not have happened to result in the incident mentioned in the OP - does anyone remember that somebody died?

This is not an inquest and none of us are in any position to know what really happened, most people here seem incapable of actually stating the truth about the attributes of the JJ-CCR, especially those that don't own one. Hopefully the facts will emerge, but that's certainly not going to happen here, even with all the armchair ability available at our disposal.

 

[Mike Ferguson]

It would appear that my shearwater controller doesn't change from 0.19 to 0.7 when you hit the water. It changes when it sees the pressure rise as you start your descent. Be very aware that at the surface while your faffing about swimming to the shot or clipping on stages it will stay on a setpoint of 0.19 and that that may not keep the ppO2 up at conciousness sustaining levels, just as you are at the most task loaded part of the dive.

I'm going to have to agree with Gian and disagree with Dave on this one.

I agree it's not in dive mode and leaving a handset set to 0.19 may be 'off' as far as the system is concerned but it's not actually the same as being off from a visual display point of view.

A quick glance at the handset in off mode and it's obvious its off because there's no display.

However a quick glance at the screen in 0.19 setpoint mode may not immediately reveal anything is amiss. If your cell readings look OK and everything on the screen is green you may not realise you are still on a 0.19 setpoint as you jump. It is not immediately obvious you have an issue as the display looks superficially 'normal' and maybe even something as simple as changing the screen colours when set to 0.19 would make it immediately obvious you are on a 0.19 setpoint?

I am very aware that this thread is discussing a fatality and no one seems to know what happened here and that's the problem. Everyone is scratching about trying to make sense of something that may have a very simple answer. maybe the mods should split the thread as this has gone off at a tangent as usual.

 

[Ben Field]

It would appear that my shearwater controller doesn't change from 0.19 to 0.7 when you hit the water. It changes when it sees the pressure rise as you start your descent.

Why would you have a loop at 0.19 when you hit the water?!

 

[Dave Sutton]

Gian, Don't be obtuse.

0.19 is the substitute for SOLENOID OFF.

.

It's USED exactly like MAN on a Meg.

IsCAN on Meg Pathfinder has this at 0.20

It is designed as a soft "solenoid off" mode for rig servicing in air or for taking control of the rig manually in the water.



Dave

.

 

[gianaameri]

Gian, Don't be obtuse.

0.19 is the substitute for SOLENOID OFF.

.

It's USED exactly like MAN on a Meg.

IsCAN on Meg Pathfinder has this at 0.20

It is designed as a soft "solenoid off" mode for rig servicing in air or for taking control of the rig manually in the water.

Dave

.

If people make mistakes and have accidents or potential accidents or actual accidents or can have actual accidents due to a display feature/interface, common sense dictates the display feature/interface be improved.

What if this one diver had jumped in with the JJ Controller set to ON, but a Setpoint of 0.19?

Could have he jumped in with the JJ Controller set to ON, but a Setpoint of 0.19?

Wherever possible, you have to design out the possibility for Human Error.

Also, wherever practicable, you have to find a technique which is effective in most circumstances, if not all, rather than one which works only subject to some prior set of conditions being satisfied.

 

[MeRodent]

However a quick glance at the screen in 0.19 setpoint mode may not immediately reveal anything is amiss. If your cell readings look OK and everything on the screen is green you may not realise you are still on a 0.19 setpoint as you jump. It is not immediately obvious you have an issue as the display looks superficially 'normal' and maybe even something as simple as changing the screen colours when set to 0.19 would make it immediately obvious you are on a 0.19 setpoint?

The shearwater will flash the PPO2 in red if it drops below 0.4, in addition if the set point is set to .19 it displays it in amber (as a warning), however the set point is not shown on the primary display, to check it you need to switch to the next screen.

 

[nickb]

I still don't see the need for this option/facility.

Useful for cell testing. Without this function the solenoid will be constantly firing until you've reached the low setpoint.

 

[Mr Walker]

I still don't see the need for this option/facility.

Just played with my Inspo Vision head. If I need to upgrade software or download dive history, it's connected to a PC & the software detects this. The Vision starts up in a specific PC interface mode. Otherwise it starts up in Surface mode. It ALWAYS does battery test & other checks then buzzer starts up because it can't make SP & the solenoid clicks away. There is no way to stop it. You can adjust the "low set-point" that it's trying to achieve, but the lowest you can set it is 0.5, so cannot set low enough to stop solenoid operating.

Looks like a strange design feature to me & potentially dangerous [just my opinion which I realise isn't worth much ]

.

Also wet switches defies logic.

First we agree on the importance of knowing everything about our unit and how to work/dive it.
Then we agree on the importance of proper set up and use of checklists so that absolutley nothing is forgotten.
Then we agree on the importance of prebreathing so that we can check function of unit by listening to solenoid, watching handsets etc before jumping in water.
And from beginning of all RB-diving we are told to always know our pO2.

And then wetswithches comes along so that we can skip all the above and just jump in the water???

No wonder Martin Parker and Nigel Hester decided against wet switches on the Vision controller.

/nils

 

[Randy Thornton]

Also wet switches defies logic.

First we agree on the importance of knowing everything about our unit and how to work/dive it.
Then we agree on the importance of proper set up and use of checklists so that absolutley nothing is forgotten.
Then we agree on the importance of prebreathing so that we can check function of unit by listening to solenoid, watching handsets etc before jumping in water.
And from beginning of all RB-diving we are told to always know our pO2.

And then wetswithches comes along so that we can skip all the above and just jump in the water???

No wonder Martin Parker and Nigel Hester decided against wet switches on the Vision controller.

/nils

Nils,

I don't think that anyone on any level is suggesting that we don't follow our pre-dive sequences and protocols in an exacting manner. This is obviously THE most important thing that any CCR diver can do regardless of what make or model unit we are diving! All of the various safety features of the various units are simply there for when we do make a mistake, whatever that might be! Anyone who thinks otherwise is a fatality waiting to happen IMHO.

My rule of thumb is "only trust myself". Everything else, including equipment, electronics etc. is "trust but verify!" (Wasn't it Winston Churchill that coined that phrase?)

Regards,
Randy

 

[Mr Walker]

Nils,

I don't think that anyone on any level is suggesting that we don't follow our pre-dive sequences and protocols in an exacting manner. This is obviously THE most important thing that any CCR diver can do regardless of what make or model unit we are diving! All of the various safety features of the various units are simply there for when we do make a mistake, whatever that might be! Anyone who thinks otherwise is a fatality waiting to happen IMHO.

My rule of thumb is "only trust myself". Everything else, including equipment, electronics etc. is "trust but verify!" (Wasn't it Winston Churchill that coined that phrase?)

Regards,
Randy

Agreed that it's obviously important to do predive check. But I also think it's all to obvious that it's not always done. Probably because the diver has come to trust his machine.
One of the arguments against wet swithches on the Inspo was that they don't work well or perhaps not at all in fresh water. So rather than introducing wet switches as a parachute that not always will open and therefore can't be trusted they decided against it. Unless I've missed something I believe that this accident happend in fresh water.

/nils

 

[Mike Ferguson]

One of the arguments against wet swithches on the Inspo was that they don't work well or perhaps not at all in fresh water. So rather than introducing wet switches as a parachute that not always will open and therefore can't be trusted they decided against it.

/nils

I haven't heard of issues with wet contacts since the early aladin computer with graphite wet contacts, and uwatec solved that problem years ago. I must have done well over 1500 dives using an aladin pro and another 200 - 300 with a uwatec galileo with wet contacts. I can't recall either failing to turn on when hitting the water, salt or fresh.

 

[Randy Thornton]

Nils,

Since this thread is already hopelessly off track, I guess I'll contribute even more by responding to your post. I must respectfully disagree with your comment that wet switches contribute to increase in lack of attention to pre-dive protocols. I believe if you were to look at actual fatalities and near misses, you will find equal prorated numbers of divers doing stupid things like jumping in the water with o2 turned off on all different units. (Again, I am not implying this what happened in this case)
Units without wet switches do not show lower fatalities , from what I can see.

Regards,
Randy