Fiona Sharp death in Bonaire

[John Bantin]

I was shocked to hear of Fi Fi's death. She was a very clever woman, who one would think knew what she was doing. I've been party to info downloaded from her unit. I suggest you all wait until full information is disclosed in the proper way.

 

[RVBldr]

I respectfully disagree with you.

1. This is none like an aviation accident. The field is heavily regulated, the planning is recorded and a formal risk assessment is done and left on record. The supervisor will assess that risk and endorse planning and execution. Once the accident happens all of this is analysed and conclusions are drawn, procedures are changed and fleets are ground until remedial action is in place.

The original comparison on speculation is very close to our US General Aviation incidents when we lose an experimental or other small GA aircraft operating under Part 91. There's no supervisor to assess risk and endorse the flight plan, it's up to the owner/pilot. There may be some evidence of a flight briefing if it's taken from a certified source, including NOTAMs and weather, but not always, depending on avionics, there may or may not be actual flight data, and the incident pilot may or may not be under ATC control. When a pilot is lost the forum responses seem to be very similar, however, there will at be an NTSB accident report issued publicly with known facts, unlike diving accidents.

 

[tursiops]

I suggest you all wait until full information is disclosed in the proper way.

It's a nice thought, but I can't actually remember a case where "full information has been disclosed in the proper way." Do you have reason to think this case will be different?

 

[silent running]

I wonder why most re-breathers only have 3 cells? Cost?
Mine runs 5 cells, 3 into the controller, 2 into a Nerd, that's true redundancy. I personally don't like the 3 cell only rigs (not the rigs themselves as such, but the logic of only 3 cells and piggybacking off two of them for the backup). With a 5 cell unit, You can lose 2 cells and its still a div-able rig.

I also like split canisters so even if one breaks through the sorb due to poor packing, the other should pick it up so minimising the risk of a CO2 hit. Maybe its just me but I do like redundancy, particularly with re-breathers. I can lose the controller and still stay on the loop by driving it manually and using the Nerd. I can lose the solenoid and stay on the loop and drive it manually. Controller battery goes flat, drive it manually.

The only thing not truly backed up is operator error (although if its in auto it should try and keep you alive, which is a good thing but it wont save one from stupidity)

Because 3 cells are sufficient for the voting logic of most set point controllers. Good controllers track cell performance during the dive and vote them out if the expected response is not registered. I’ve never had more than one voted out and whenever one is voted out, I check the other two with a diluent flush. Sometimes cells are temporarily voted out because of their response time, and come back into line during the course of the dive. Theoretically, you can dive with one cell which is properly functioning, but if I had two fail, I’d probably just bail out.

Cell redundancy and electronics redundancy are two separate issues. Voting logic takes care of cell redundancy, 3 cells = redundancy. Electronics redundancy is to the taste of each diver. I adhere to the KISS principle in my ECCR diving, and my unit is the simplest ECCR possible, an SP only controller with a Smithers code HUD and an analog gage that is driven by the sensor voltage directly. The analog gauge is my electronics redundancy, and requires no computer or battery power to know my PO2.

I do not want to calibrate and manage 5 cells and 2 computers, that’s extra work before, during and after the dive. Cell failure modes are known and diagnosable on the fly, and if you test the cells for linearity up to 1.6 while doing your last deco stop or your safety stop at 6m and know how to do an effective diluent flush, 3 cells and your brain are enough to know your PO2.

For me, watching 15 blinking digits and paying attention to two different computers is too much distraction from the dive, and introduces more complexity and things that can go wrong...

 

[fsardone]

You are a pilot & CCR diver. So, a question for you. To become a pilot, you do some flight simulations before actually doing the flight training. Is there similar diving simulation training to become CCR diver, such as entering your breathing rate, dive plan (depth & bottom time), number and sizes of bailout bottles, gas composition in the bailout bottles, different failure scenarios, etc.?

Quite an interesting avenue of thinking.
The way I was trained in flying (twice as a civilian in Italy and US under FAR) and once under military rules flying came first.
We did the initial rudder and stick training directly one SEP (Single Engin Pistons). Then simulators came when mission and equipment became so complex that it would be beneficial to train at lower cost and risk and then redo it in flying.

This could be compared to learn open water actually diving, learning the reb in a classroom and then go dive. Which is actually what we did in my MOD 1. The big difference is you cannot simulate actual emergencies in a REB (you can use cue cards but you miss the analysis bit of understanding what the issue is) but you actually do it in a flying simulator. When you mess up the sim instructor just tells you that you messed up and you are dead. Try again ... This cannot be simulated in a rebreather.

 

[fsardone]

The original comparison on speculation is very close to our US General Aviation incidents when we lose an experimental or other small GA aircraft operating under Part 91. There's no supervisor to assess risk and endorse the flight plan, it's up to the owner/pilot. There may be some evidence of a flight briefing if it's taken from a certified source, including NOTAMs and weather, but not always, depending on avionics, there may or may not be actual flight data, and the incident pilot may or may not be under ATC control. When a pilot is lost the forum responses seem to be very similar, however, there will at be an NTSB accident report issued publicly with known facts, unlike diving accidents.

Agree.
I am a FAA ASEL CPL IFR Rated and Advanced Ground instructor. I am well aware. But if the event is classified as an accident according to FAR 830.2 it requires immediate notification to NTSB (according to FAR 830.5) and there will be a formal enquiry. The results will be public. So, I can accept the refrain to speculate in such case but I do not understand it in case of scuba accidents.

Also, the flying community speculates anyway for the same reasons we do.

 

[fsardone]

As I dont know the Inspiration CCR and how it operates? Perhaps someone could enlighten me on the difference to a REVO?

Does the Inspo have 3 cells? Is it hybrid or manual or fully auto?

Is the canister a single one or two separate ones?

I dive Inspiration with vision and 2020 handset.
It is a single axial scrubber configuration 2.5 Kg
3 Cells with 2 controller monitoring ppO2 that have the capability to back each other up in case of setpoint lowering .2 bar below setpoint.
Dual battery.
Head up display run directly from the controllers, you can dive the inspo full auto even without the handset (you loose ppo2 readout but you still have the HUD and also lose the capability to shut dow the reb and to change set point).
It is a full auto eCCR quite sturdy and reliable I would say.

 

[foob]

It's a nice thought, but I can't actually remember a case where "full information has been disclosed in the proper way." Do you have reason to think this case will be different?

There's no NTSB investigation. Coroner's reports never get posted. I'm not sure what to be waiting for.

But I'm not part of this conversation either.

 

[doctormike]

You are a pilot & CCR diver. So, a question for you. To become a pilot, you do some flight simulations before actually doing the flight training. Is there similar diving simulation training to become CCR diver, such as entering your breathing rate, dive plan (depth & bottom time), number and sizes of bailout bottles, gas composition in the bailout bottles, different failure scenarios, etc.?

This is a good question, and I actually think that CCR training would lend itself very well to a simulator, since you have to think through more alternatives and have more options in failure scenarios than you do in OC. I actually tried to get some people interested in doing that a few years ago - doesn't seem like it would be a very difficult thing from a programming point of view. Unlike flight simulators (which are available for recreational gamers), you wouldn't have to model physics and motion, just your controller readouts.

I believe that many years ago, Innerspace had a Meg simulator available for PCs. I tried playing it in virtual PC, didn't get very far. But this would be a great project for someone with experience writing web based or mobile games.

 

[fsardone]

This is a good question, and I actually think that CCR training would lend itself very well to a simulator, since you have to think through more alternatives and have more options in failure scenarios than you do in OC. I actually tried to get some people interested in doing that a few years ago - doesn't seem like it would be a very difficult thing from a programming point of view. Unlike flight simulators (which are available for recreational gamers), you wouldn't have to model physics and motion, just your controller readouts.

I believe that many years ago, Innerspace had a Meg simulator available for PCs. I tried playing it in virtual PC, didn't get very far. But this would be a great project for someone with experience writing web based or mobile games.

The way simulation works is showing your analog brain scenarios to be recognized without intelligent thought.
Let me explain in a very low level (apologies to those who are expert in the field ...)
Our brain works in two main ways to make decisions:
-recognising a scenario and using a precanned solution this saves sugar (the brain energy) and it is fast;
-analysing a situation in a methodological way based on the available data, it takes effort a lot of sugar and it is slow.
Our brain is always trying to save "computational power" therefore whenever possible it will use technique 1. If in the catalog of the precanned solution it does not find something (and recognise the lack of a solution) it will start process number 2. Failure of recognising the absence of a precanned solution, or applying the wrong precanned solution (failure of recognising a deviating scenario) leads to decision making process mistakes.

Expert do less mistakes because they have done more of them and survived .... So they have a bigger catalogue to choose from.

Now simulators just build the catalogue. The problem is the level of realism to recognise a given situation, while busy doing the rest of the activities. The kind of simulator you are proposing are simulatore that ONCE YOU HAVE identified the problem let you work out the solution. I would argue that the most valuable part of a simulation is learning to recognise a situation. My rebreather has a simulator mode that shows me and allows me to handle the reb display and buttons on the surface. Same with my dive computer.

Just my 2c on this.

I AM GOING TO REPORT THIS POST: because I believe it is inappropriate to discuss simulators in the a&i forum
Suggest to MOD's (cold not tag @The Mod Squad) to split #148, #155, #156 and this in a thread in the Rebreather Diving forum titled: "Rebreather simulator as training aid" less this paragraph. Or similar solution deemed suitable.