Diving and flying

[Landau]

BTW where did you see the guidelines about not diving AFTER flying?

I'd also like more info on this. I've never heard of it before. I've done my first dive on a liveaboard somewhere around 5 hours after getting off the plane.

 

[scubadada]

Hi @Sbiriguda

In the end, your choices are your own and you take responsibility for them.

I dive pretty aggressively with fairly liberal computers, I take that risk. However, I have never skipped a deco stop and I have never violated the no fly rules.

Though I have always followed the no fly rules, I have often noted the desaturation times displayed by some of my dive computers. I have never read about the accuracy of these calculations and would not rely on them. Sometimes they have been lower than the suggested no fly times, sometimes they have been higher. Of note, I have been able to generate desaturation times of greater than 24 hours on numerous occasions. Most eye opening is that when diving two different brands of computer, there have frequently been very significantly different displays of desaturation time. My Shearwater Teric does not display a desaturation time. Shearwater recommends following the recommended no fly times, erring on the conservative side. However, I can take a look at the tissue loading graphic.

 

[Sbiriguda]

BTW where did you see the guidelines about not diving AFTER flying? I don't mean of course exhausting long haul (eg more than a day long) flights. But I think diving after a 2-3-4 hours flight followed by a couple of hours of commute + some rest, time to unpack etc is fine assuming one keeps hydrated etc (we are talking about easy rec dives of course)...

I just remember this as a recommendation (not mandatory as I said in the beginning), perhaps it was meant only for long flights like you said

 

[Searcaigh]

I did two dives there last November and I was not impressed at all.

Really?

There are some good wrecks around Aqaba, but I wouldn't fly there for a weekend.

 

[Mike Beck]

Really the only issues with diving after flying is fatigue and dehydration.

 

[ontdiver]

While I get it that some folks are curious about what is involved in pushing the envelope - after all, the backdrop to diving is physics, engineering, etc - I would really prefer that those who want to violate no fly rules first consider the impact that their decision may have have on medical resources that are heavily strained.

 

[boulderjohn]

Well let's say so. On Friday afternoon I fly to Aqaba. I sleep there I do 2 dives on Saturday morning and afternoon, whatever the dive depth. Then I wake up on Sunday morning and make 1 shallow dive. No dives in the afternoon. Then I take a flight on the way back late at night, or early Monday morning. 12 hours or 18 hours AFTER the last dive. Moreover, I can do snorkeling all the time I spend there. Freediving I don't know, because I never go freediving alone, so I could do that only if I find a buddy there. Given I am healthy and strong young man (more or less) that should be ok and well within the limits set by PADI and by common sense

From your answers I understand anyway that it is mandatory to follow this rule no exceptions

My resource page has an article on ascending to altitude after diving that my help you. It includes the US Navy information Tursiops mentioned earlier.

The diving you describe here is well within the US Navy limits, and it is within the PADI and DAN America recommendations. It is outside the DAN Europe recommendations, which are very conservative.

 

[Angelo Farina]

As for the dive in the morning, and then flying in the late afternoon or evening, I would prefer a short, deep dive than a long dive at shallow depth.
The first will load of nitrogen your fast tissues, which will desaturate quickly. Instead, a long dive at, say, less than 10 meters, causes your slow tissues to get a significant amount of nitrogen. This will last in your body for several hours...
Modern "tech" computers should allow you to see the amount of nitrogen still remaining in each of your tissues (called often "compartments" on computers) after surfacing. When they all are at zero, you can fly safely.
You can also use some existing Excel spreadsheet for running simulations, and verify what I affirmed here above.

 

[NothingClever]

@Sbiriguda

What gas are you breathing on your last dives?

Staying shallow is obviously smart. If I'm not mistaken, tissue loading doesn't happen in earnest until 8m so staying shy of that is helpful.

But if you're pushing the time envelope, I'd get off the 21% and breathe a higher EANX gas. It won't eliminate the possibility of problems but will likely decrease tissue loading, mitigate the probability of problems occurring and the severity if a problem does occur.

Obviously you have to gauge your own levels of risk and be scientific about implementation of the measures to mitigate problems (ie., setting hydration goals and counting your liters, undistracted sleep, don't be a dork and booze it up, etc). I think walking several kilometers sometime after your dive is also helpful to stimulate N2 dissipation.

Might be wise to find a pilot that dives to figure out how they mitigate tissue problems.

 

[Angelo Farina]

Well, if you dive with a CC pure oxygen rebreather (ARO) you will not get any Nitrogen added.
Current recommendations are to not exceed 6m depth with these units, albeit I am certified for using them down to 10m.
When young, I and my wife did use them several times down to 12m, with the trick of starting with
the counterlung full of air, instead of pure oxygen.
CC Rebreathers require specific training, but can be the solution for your problem.
You could also consider Nitrox at 50% in OC.
It has a maximum depth of 22m (at ppO2=1.6 bar), but you should stay much shallower if you want to keep the ppN2 as the same value as atmospheric air, that is 0.78 bar. You reach this pp at approximately 6 m.