Complacency kills - It's not just an empty threat!

[RTC'83]

Glad you are ok, scary.
Thanks for posting

 

[RyanT]

Yes, thanks for the post. To echo @Jack Hammer, I found the timeline especially informative. Thanks again and I'm really glad things turned out OK for you!

 

[hroark2112]

Awesome writeup... thanks so much for sharing! So glad that you are still with us. Excellent point about the wing, I always jump with a full wing. I avoid dive plans where a negative entry is required.

I would like to ask some questions about the accident. Please read this in the spirit that was intended, and presumably in the spirit that you posted - the goal being to learn and to become safer divers. I'm a newby, and I know that any of us could have a similar problem.

While there were certainly mechanical problems with the unit, it seems that the accident was caused by pilot issues. A malfunctioning solenoid control system shouldn't cause any serious problem if the PO2 is being monitored (as you pointed out).

Questions:

1) Hypoxic dil?

2) Do you normally follow a printed pre-flight checklist? Not a build checklist, but a checklist once you are in the unit?

3) Do you normally do a pre-breathe, either as part of a checklist or otherwise?

4) What do you think that the issue was that prevented you from noticing the dropping PO2? Being rushed? Otherwise distracted? HUD problem?

Again, thanks for the post!

I totally get the spirit in which this is intended. 100% no offense taken by your questions!

The mechanical issues should have kept me out of the water, or at the bare minimum made me be very diligent in my dive preparations. At the beginning of the week I was, but as the week went on I obviously lapsed.

Diluent mix was 18/35.

I normally follow the TDI pre-flight card.

My normal preflight includes prebreathing and watching to make sure the unit maintains .5 on my handset and NERD.

The issue was a combination of being rushed (please note this was all on me, my buddy did not say a word to rush me in any way!) and the "everything has been good for the last few days, I'll jump in and we're off!" thought process that let me short my normal pre-dive. I don't remember looking at my NERD at all, I may have but I just do not remember.

 

[doctormike]

I totally get the spirit in which this is intended. 100% no offense taken by your questions!

The mechanical issues should have kept me out of the water, or at the bare minimum made me be very diligent in my dive preparations. At the beginning of the week I was, but as the week went on I obviously lapsed.

Diluent mix was 18/35.

I normally follow the TDI pre-flight card.

My normal preflight includes prebreathing and watching to make sure the unit maintains .5 on my handset and NERD.

The issue was a combination of being rushed (please note this was all on me, my buddy did not say a word to rush me in any way!) and the "everything has been good for the last few days, I'll jump in and we're off!" thought process that let me short my normal pre-dive. I don't remember looking at my NERD at all, I may have but I just do not remember.

Thanks for the replies, and I'm glad that you didn't take offense at my questions! Whenever the term "pilot error" is used, it's easy to see that as a pejorative. We are all human, we all make errors, so the best efforts at improving safety are directed at setting up failsafes that break the incident chain when the inevitable error is made.

Your case reminds me a lot of the recent tragedy in Hawaii, where a hypoxic trimix student jumped in ahead of his instructor, carrying a camera, with his O2 off and the CCR in surface mode. This is what got me thinking about streamlining the pre-flight checklist process, and making that sticker so that the checklist is always right there in front of you.

In those discussions, there was a lot of confusion about pre-flight vs. build checklists (which include positive and negative tests, calibration, etc..). I strongly believe that the pre-flight checklist should be done once you are in the unit, just before you splash. It's too easy for something to change in the donning process (valve rolloff, disconnected LP hose, etc..). I put the unit on, and run through that printed checklist before I jump.

I guess the best takehome from your incident is in your last paragraph. Don't rush, don't cut corners, don't normalize deviance.

Thanks again!

 

[hroark2112]

When the details of that incident came out, it really hammered home the lessons I learned. I may even have them tattooed on my hand so I never am without them! (kidding....kind of!)

Unless it's necessary, go in very positive. If I have to go in negative, double check everything else before splashing!
Pre-breathe the unit to ensure the solenoid is firing and both computers are reading properly.
Nothing is so important that I have to rush. The wreck will still be there when I get in the water. Making another diver wait a few extra minutes is way better than making them miss the dive so they can race my dead azz to the emergency room!
Most important of all - Never start a dive with a known issue! Fix it or thumb the dive.

 

[TrimixToo]

Thanks for sharing the details of this incident. I don't think I've ever read such a detailed account of a PPO2 blackout incident before. It's a bit scary just how fast that can happen, even before you really started the dive.

I'll add my thanks for posting.

I'll also add that I have had a non-diving-related experience with hypoxia. I will not go into any detail, but for me there was *no* warning at all. I was awake and alert...and then I wasn't. Just like that, I was out.

 

[hroark2112]

I'll add my thanks for posting.

I'll also add that I have had a non-diving-related experience with hypoxia. I will not go into any detail, but for me there was *no* warning at all. I was awake and alert...and then I wasn't. Just like that, I was out.

Glad you’re ok too!! A very unnerving feeling, regaining consciousness and wondering what the hell happened!

 

[JohnnyC]

Glad you're still alive.

It takes a lot of balls to admit that you screwed up, passed out, and woke up realizing you'd **** your pants and had a bunch of people keeping you alive. Excellent post, the timeline is super helpful. And honestly and truly glad you're still kicking, and so able and willing to share your experiences. Thanks a bunch for being so honest and straightforward, and it's a great reminder to all of us.

 

[boulderjohn]

IMO, this is the biggest lesson for those following the thread.

The issue was a combination of being rushed (please note this was all on me, my buddy did not say a word to rush me in any way!) and the "everything has been good for the last few days, I'll jump in and we're off!" thought process that let me short my normal pre-dive.

For some reason, I have been a slow dresser my whole life, and that characteristic has followed me into technical diving. I am pretty fast with single tanks, but in tech diving, I am frequently a bit behind everyone else--including my students. I have made enough minor mistakes while rushing (caught during final checks) to make it a mantra in my instruction. When you are behind everyone else, you will feel pressured to hurry up, even if your teammates are not hinting in any way they would like you to get going. When you feel that pressure, you are more likely to make an error, an error that could be fatal. When you realize you are behind everyone, you need to do the opposite of that tendency and slow down to make sure you are not making a mistake.

 

[RyanT]

For some reason, I have been a slow dresser my whole life, and that characteristic has followed me into technical diving. I am pretty fast with single tanks, but in tech diving, I am frequently a bit behind everyone else--including my students. I have made enough minor mistakes while rushing (caught during final checks) to make it a mantra in my instruction. When you are behind everyone else, you will feel pressured to hurry up, even if your teammates are not hinting in any way they would like you to get going. When you feel that pressure, you are more likely to make an error, an error that could be fatal. When you realize you are behind everyone, you need to do the opposite of that tendency and slow down to make sure you are not making a mistake.

This!

I actually ran out of air once...at the start of the dive. I grabbed an empty tank and in my rush to catch up with my buddy, didn't look at the spg.