Another flying after diving Q

[RDRINK25]

So I am planning a dive trip weekend. Wanted to see if anyone could help with some off gassing info. I am planning a 2 tank dive with EAN to no more the 80' without getting into deco. Followed by another day of 2 tanks using EAN to 70' or so not getting into deco. Then followed by an early morning dive to 15' MAX but need to be on a plane 12 hrs later. I know the risks but what is a dive to 15' really going to do?

 

[filmguy123]

I also want to piggy back on this thread (not hijack) and ask for info on this... would be curious to learn a bit more about the WHY behind this in more detail, and at what point it does become a factor and how much so.

For example, the OP asks if diving only 15' before flying will be a big deal. Likewise, I am wondering if diving to 60 feet and then staying at lodging that evening which is a bit elevated - say 700' above sea level - and then coming back in morning and diving again the next day, then going back to the same lodging, would be a problem. And if so, why, and what's the "safe" threshold and how does that risk factor work and relate to dive depth, time, etc.?

Figured I'd keep the question here with the OP as it's very similar, rather than starting another thread.

Thanks!

 

[Altamira]

Check DAN's Alert Diver website www.alertdiver.com Flying After Diving article, and read what they have to say.

 

[northernone]

During the flight, in case of prolonged lost cabin pressure your 15ft foot dive because an extreme high altitude dive and may (hypothetically) get you bent. I am not aware of altitude tables high enough to accurately predict the risk. You could take your life in your hands doing math to make your own hypothetical dive table for a 15ft dive NDL time but understand that would be a crap shoot.

...as far as I'm concerned if I am flying and the plane loses pressure long enough for me to get bent the least of my worries is getting bent. People who have decided their life to the study dcs have given warnings, our personal risk tolerance may differ.

There's some great old threads I've enjoyed on this.


In the words of an unsung hero... "My opinion is worth exactly what you paid for it."

 

[kcprofessor]

Think about the physiology of DCS and off-gassing. If the supersaturation in your tissues is low enough, you off-gas slowly enough that bubbles are not symptomatic. The same thing happens in an airplane. Your body is trying to equalize with the reduced gas pressure in the cabin. Every passenger on the plane is in effect decompressing. The danger for scuba divers is that they may have an elevated tissue gas pressure and the difference in pressures between the gasses in the blood and in the tissues becomes great enough to produce symptomatic bubbles.
So how does your 15' morning dive affect you? How long is your dive? What is your breathing mix? How much residual nitrogen are you carrying from your previous dives? Your faster tissues would be clear before your flight but the slowest tissues may well not be.
If it were me, I would think of doing the 15' dive as a third dive and getting a few more consecutive hours of surface interval. As a certified diver, the choice is yours, however.

 

[Bob DBF]

For example, the OP asks if diving only 15' before flying will be a big deal. Likewise, I am wondering if diving to 60 feet and then staying at lodging that evening which is a bit elevated - say 700' above sea level - and then coming back in morning and diving again the next day, then going back to the same lodging, would be a problem. And if so, why, and what's the "safe" threshold and how does that risk factor work and relate to dive depth, time, etc.?

As others have said, it's not just the 15' dive but also the prior dives that add up.

The altitude tables have 1000' incrments so I would adjust for that when increasing elevation over 500', but I'm old and plan to stay that way.

I dive Iake Tahoe, sometimes deep, and always plan on staying overnight before going over the pass. A good SI would would work but I like the area and am in no hurry to leave anyhow.

The only time I got bent was on an altitude dive so I am very conservative with diving and altitude since. As much as we would like look at deco as black and white, it is actually gray. It is even grayer when you add in altitude. In a plane the altitude is 8000' plus or minus, if nothing goes wrong. You just decide what you are comfortable with, and proceed.


Bob

 

[Altamira]

DAN recommends a minimum of 18 hours between diving and flying for multiple day dives, and the US Air Force requires a minimum of 24 hours. As a retired USAF and commercial airline pilot, I have always used the 24 hour minimum surface interval rather than the minimum because I am fully aware of, and understand, the very real possibility of a rapid decompression at high altitude. If you think a rapid decompression is an anomaly, you should be aware that pilots are routinely tested on this emergency procedure during annual and semi-annual flight evaluations. I can assure you that because of the high cost and limited time available for testing on emergency procedures in the flight simulator, we got tested on the emergencies that do happen, and not on the "flukes." Frankly, I have never understood the mentality of otherwise intelligent people that think an extra hour under water is worth the potential lifetime of hell that can follow a DCS hit.

 

[yle]

Likewise, I am wondering if diving to 60 feet and then staying at lodging that evening which is a bit elevated - say 700' above sea level - and then coming back in morning and diving again the next day, then going back to the same lodging, would be a problem. And if so, why, and what's the "safe" threshold and how does that risk factor work and relate to dive depth, time, etc.?

I've often done beach dives on Saturday and Sunday, going back home in between. Home is at an elevation of around 1000 feet. I've never had a problem and I've never even thought of it. I can't imagine that what you describe, driving to an elevation of 700 feet after diving, would be an issue.

 

[CuzzA]

At 15', why not just snorkel/freedive and forget the tanks?

 

[redacted]

If that last dive is important, i would use the divenav simulation to baseline compartment loading for a variety of single tank dives after a 12 hr SI. Iwould compare those loadings with the compartment loading after your planned series of dives.